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JDBC驱动初始化-Mysql:http://donald-draper.iteye.com/admin/blogs/2342010
MySQL读写分离又一好办法 使用 com.mysql.jdbc.ReplicationDriver :
http://www.cnblogs.com/taven/archive/2013/04/24/3040489.html
Configuring Master/Slave Replication with Connector/J:
http://dev.mysql.com/doc/connector-j/5.1/en/connector-j-master-slave-replication-connection.html
JDBC访问Mysql进行读写分离测试:http://blog.csdn.net/hzw2312/article/details/9145307
Configuring Load Balancing with Connector/J:
http://dev.mysql.com/doc/connector-j/5.1/en/connector-j-usagenotes-j2ee-concepts-managing-load-balanced-connections.html
DatabaseMetaData:http://blog.csdn.net/anxinliu2011/article/details/7560511
上一篇,我们探究了一下驱动的初始化,今天,我们来看一下如何从驱动管理器获取连接。
下面来看如果从DriverManager获取连接:
//DriverManager
//获取连接,将user和password放到Properties,将工作委托给
下面我们来看com.mysql.jdbc.Driver如何获取连接
查看NonRegisteringDriver
//NonRegisteringDriver
连接的获取这一部分有3个点我们分别来看:
1.
//如果url以jdbc:mysql:loadbalance://则调用负载均衡连接获取方法
if(StringUtils.startsWithIgnoreCase(url, "jdbc:mysql:loadbalance://"))
return connectLoadBalanced(url, info);
2.
//如果url以jdbc:mysql:replication://则调用集群连接获取方法
if(StringUtils.startsWithIgnoreCase(url, "jdbc:mysql:replication://"))
return connectReplicationConnection(url, info);
3.
//解析url
if((props = parseURL(url, info)) == null)
return null;
//获取mysql连接
com.mysql.jdbc.Connection newConn = ConnectionImpl.getInstance(host(props), port(props), props, database(props), url);
我们先看获取单个Server的连接
//解析url
从上我们可以看出url解析实际上,是解析出host,port,db,查询参数
//获取mysql连接
//ConnectionImpl
先看ConnectionImpl,
//ConnectionImpl
//初始化驱动属性
initializeDriverProperties(info);
//初始化数据库元数据信息
//private DatabaseMetaData dbmd;
dbmd = getMetaData(false, false);
//创建MysqlIO
createNewIO(false);
//初始化mysqlStatement拦截器
initializeStatementInterceptors();
//设置IO拦截器
//关闭mysqlIO
从上面的分析,可以看出从DriverManager获取连接,实际上是事委托给com.mysql.jdbc.Driver,com.mysql.jdbc.Driver实际调用的是NonRegisteringDriver获取连接方法,首先分析url,如果url以jdbc:mysql:loadbalance://或jdbc:mysql:replication://开头,则调用负载均衡,集群的连接获取方法;如果是单机服务器,根据jdbc4的属性,创建相应的连接;如果不是jdbc4类型,则创建ConnectionImpl实例,初始化连接事务级别,db信息,autoCommit,readonly等属性,初始化驱动属性,创建PreparedStatement缓存,设置CallableStatement缓存,设置结果集缓存,初始化数据库元数据信息DatabaseMetaData,创建MysqlIO,初始化mysqlStatement拦截器,设置IO拦截器。
下面来看一下jdbc4连接:
//JDBC4Connection
从上面可以看出JDBC4Connection是ConnectionImpl的包装。
至此mysql连接的获取讲完,下一篇,看一下集群及负载均衡的连接获取 。
//NonRegisteringDriver
//ConnectionImpl
//DatabaseMetaData
//Util
MySQL读写分离又一好办法 使用 com.mysql.jdbc.ReplicationDriver :
http://www.cnblogs.com/taven/archive/2013/04/24/3040489.html
Configuring Master/Slave Replication with Connector/J:
http://dev.mysql.com/doc/connector-j/5.1/en/connector-j-master-slave-replication-connection.html
JDBC访问Mysql进行读写分离测试:http://blog.csdn.net/hzw2312/article/details/9145307
Configuring Load Balancing with Connector/J:
http://dev.mysql.com/doc/connector-j/5.1/en/connector-j-usagenotes-j2ee-concepts-managing-load-balanced-connections.html
DatabaseMetaData:http://blog.csdn.net/anxinliu2011/article/details/7560511
上一篇,我们探究了一下驱动的初始化,今天,我们来看一下如何从驱动管理器获取连接。
下面来看如果从DriverManager获取连接:
con = DriverManager.getConnection(url, user, password);
//DriverManager
//获取连接,将user和password放到Properties,将工作委托给
public static Connection getConnection(String url, String user, String password) throws SQLException { java.util.Properties info = new java.util.Properties(); // Gets the classloader of the code that called this method, may // be null. ClassLoader callerCL = DriverManager.getCallerClassLoader(); if (user != null) { info.put("user", user); } if (password != null) { info.put("password", password); } return (getConnection(url, info, callerCL)); } //获取类加载器 /* Returns the caller's class loader, or null if none */ private static native ClassLoader getCallerClassLoader(); //连接的获取 // Worker method called by the public getConnection() methods. private static Connection getConnection( String url, java.util.Properties info, ClassLoader callerCL) throws SQLException { java.util.Vector drivers = null; /* * When callerCl is null, we should check the application's * (which is invoking this class indirectly) * classloader, so that the JDBC driver class outside rt.jar * can be loaded from here. */ synchronized(DriverManager.class) { // synchronize loading of the correct classloader. if(callerCL == null) { callerCL = Thread.currentThread().getContextClassLoader(); } } if(url == null) { throw new SQLException("The url cannot be null", "08001"); } println("DriverManager.getConnection(\"" + url + "\")"); //如果没有初始化,先初始化,这部分,我们在上一篇,已经说过,这里不再赘述 if (!initialized) { initialize(); } //copy readDrivers synchronized (DriverManager.class){ // use the readcopy of drivers drivers = readDrivers; } // Walk through the loaded drivers attempting to make a connection. // Remember the first exception that gets raised so we can reraise it. SQLException reason = null; for (int i = 0; i < drivers.size(); i++) { //从驱动集合类获取驱动 DriverInfo di = (DriverInfo)drivers.elementAt(i); // If the caller does not have permission to load the driver then // skip it. //获取合适的驱动 if ( getCallerClass(callerCL, di.driverClassName ) != di.driverClass ) { println(" skipping: " + di); continue; } try { println(" trying " + di); //从驱动获取Connection,关键在这里 Connection result = di.driver.connect(url, info); if (result != null) { // Success! println("getConnection returning " + di); return (result); } } catch (SQLException ex) { if (reason == null) { reason = ex; } } } // if we got here nobody could connect. if (reason != null) { println("getConnection failed: " + reason); throw reason; } println("getConnection: no suitable driver found for "+ url); throw new SQLException("No suitable driver found for "+ url, "08001"); }
下面我们来看com.mysql.jdbc.Driver如何获取连接
public class Driver extends NonRegisteringDriver implements java.sql.Driver { public Driver() throws SQLException { } static { try { DriverManager.registerDriver(new Driver()); } catch(SQLException E) { throw new RuntimeException("Can't register driver!"); } } }
查看NonRegisteringDriver
//NonRegisteringDriver
public class NonRegisteringDriver implements Driver { //获取连接 public Connection connect(String url, Properties info) throws SQLException { Properties props; if(url != null) { //如果url以jdbc:mysql:loadbalance://则调用负载均衡连接获取方法 if(StringUtils.startsWithIgnoreCase(url, "jdbc:mysql:loadbalance://")) return connectLoadBalanced(url, info); //如果url以jdbc:mysql:replication://则调用集群连接获取方法 if(StringUtils.startsWithIgnoreCase(url, "jdbc:mysql:replication://")) return connectReplicationConnection(url, info); } props = null; 解析url if((props = parseURL(url, info)) == null) return null; //获取mysql连接 com.mysql.jdbc.Connection newConn = ConnectionImpl.getInstance(host(props), port(props), props, database(props), url); return newConn; SQLException sqlEx; sqlEx; throw sqlEx; Exception ex; ex; SQLException sqlEx = SQLError.createSQLException(Messages.getString("NonRegisteringDriver.17") + ex.toString() + Messages.getString("NonRegisteringDriver.18"), "08001", null); sqlEx.initCause(ex); throw sqlEx; }
连接的获取这一部分有3个点我们分别来看:
1.
//如果url以jdbc:mysql:loadbalance://则调用负载均衡连接获取方法
if(StringUtils.startsWithIgnoreCase(url, "jdbc:mysql:loadbalance://"))
return connectLoadBalanced(url, info);
2.
//如果url以jdbc:mysql:replication://则调用集群连接获取方法
if(StringUtils.startsWithIgnoreCase(url, "jdbc:mysql:replication://"))
return connectReplicationConnection(url, info);
3.
//解析url
if((props = parseURL(url, info)) == null)
return null;
//获取mysql连接
com.mysql.jdbc.Connection newConn = ConnectionImpl.getInstance(host(props), port(props), props, database(props), url);
我们先看获取单个Server的连接
//解析url
public Properties parseURL(String url, Properties defaults) throws SQLException { Properties urlProps = defaults == null ? new Properties() : new Properties(defaults); if(url == null) return null; //如果url不以jdbc:mysql://开头,则返回 if(!StringUtils.startsWithIgnoreCase(url, "jdbc:mysql://") && !StringUtils.startsWithIgnoreCase(url, "jdbc:mysql:mxj://") && !StringUtils.startsWithIgnoreCase(url, "jdbc:mysql:loadbalance://") && !StringUtils.startsWithIgnoreCase(url, "jdbc:mysql:replication://")) return null; int beginningOfSlashes = url.indexOf("//"); if(StringUtils.startsWithIgnoreCase(url, "jdbc:mysql:mxj://")) urlProps.setProperty("socketFactory", "com.mysql.management.driverlaunched.ServerLauncherSocketFactory"); int index = url.indexOf("?"); //解析查询参数useUnicode=true&characterEncoding=utf8&characterSetResults=utf8 //jdbc:mysql://localhost:3306/test?useUnicode=true&characterEncoding=utf8&characterSetResults=utf8 if(index != -1) { String paramString = url.substring(index + 1, url.length()); url = url.substring(0, index); StringTokenizer queryParams = new StringTokenizer(paramString, "&"); do { if(!queryParams.hasMoreTokens()) break; String parameterValuePair = queryParams.nextToken(); int indexOfEquals = StringUtils.indexOfIgnoreCase(0, parameterValuePair, "="); String parameter = null; String value = null; if(indexOfEquals != -1) { parameter = parameterValuePair.substring(0, indexOfEquals); if(indexOfEquals + 1 < parameterValuePair.length()) value = parameterValuePair.substring(indexOfEquals + 1); } if(value != null && value.length() > 0 && parameter != null && parameter.length() > 0) try { urlProps.put(parameter, URLDecoder.decode(value, "UTF-8")); } catch(UnsupportedEncodingException badEncoding) { urlProps.put(parameter, URLDecoder.decode(value)); } catch(NoSuchMethodError nsme) { urlProps.put(parameter, URLDecoder.decode(value)); } } while(true); } url = url.substring(beginningOfSlashes + 2); String hostStuff = null; int slashIndex = url.indexOf("/"); if(slashIndex != -1) { hostStuff = url.substring(0, slashIndex); if(slashIndex + 1 < url.length()) //url中的db urlProps.put("DBNAME", url.substring(slashIndex + 1, url.length())); } else { hostStuff = url; } if(hostStuff != null && hostStuff.length() > 0) //url中host urlProps.put("HOST", hostStuff); String propertiesTransformClassName = urlProps.getProperty("propertiesTransform"); if(propertiesTransformClassName != null) try { ConnectionPropertiesTransform propTransformer = (ConnectionPropertiesTransform)Class.forName(propertiesTransformClassName).newInstance(); urlProps = propTransformer.transformProperties(urlProps); } catch(InstantiationException e) { throw SQLError.createSQLException("Unable to create properties transform instance '" + propertiesTransformClassName + "' due to underlying exception: " + e.toString(), "01S00", null); } catch(IllegalAccessException e) { throw SQLError.createSQLException("Unable to create properties transform instance '" + propertiesTransformClassName + "' due to underlying exception: " + e.toString(), "01S00", null); } catch(ClassNotFoundException e) { throw SQLError.createSQLException("Unable to create properties transform instance '" + propertiesTransformClassName + "' due to underlying exception: " + e.toString(), "01S00", null); } if(Util.isColdFusion() && urlProps.getProperty("autoConfigureForColdFusion", "true").equalsIgnoreCase("true")) { String configs = urlProps.getProperty("useConfigs"); StringBuffer newConfigs = new StringBuffer(); if(configs != null) { newConfigs.append(configs); newConfigs.append(","); } newConfigs.append("coldFusion"); urlProps.setProperty("useConfigs", newConfigs.toString()); } String configNames = null; if(defaults != null) configNames = defaults.getProperty("useConfigs"); if(configNames == null) configNames = urlProps.getProperty("useConfigs"); if(configNames != null) { List splitNames = StringUtils.split(configNames, ",", true); Properties configProps = new Properties(); Iterator namesIter = splitNames.iterator(); do { if(!namesIter.hasNext()) break; String configName = (String)namesIter.next(); try { java.io.InputStream configAsStream = getClass().getResourceAsStream("configs/" + configName + ".properties"); if(configAsStream == null) throw SQLError.createSQLException("Can't find configuration template named '" + configName + "'", "01S00", null); configProps.load(configAsStream); } catch(IOException ioEx) { SQLException sqlEx = SQLError.createSQLException("Unable to load configuration template '" + configName + "' due to underlying IOException: " + ioEx, "01S00", null); sqlEx.initCause(ioEx); throw sqlEx; } } while(true); String key; String property; for(Iterator propsIter = urlProps.keySet().iterator(); propsIter.hasNext(); configProps.setProperty(key, property)) { key = propsIter.next().toString(); property = urlProps.getProperty(key); } urlProps = configProps; } if(defaults != null) { String key; String property; for(Iterator propsIter = defaults.keySet().iterator(); propsIter.hasNext(); urlProps.setProperty(key, property)) { key = propsIter.next().toString(); property = defaults.getProperty(key); } } return urlProps; }
从上我们可以看出url解析实际上,是解析出host,port,db,查询参数
//获取mysql连接
com.mysql.jdbc.Connection newConn = ConnectionImpl.getInstance(host(props), port(props), props, database(props), url);
//ConnectionImpl
public class ConnectionImpl extends ConnectionPropertiesImpl implements Connection { private static Map mapTransIsolationNameToValue;//事务隔离级别Map private static Timer cancelTimer; private static final Constructor JDBC_4_CONNECTION_CTOR;//jdbc4Connection构造函数 private boolean autoCommit;//autoCommit private Map cachedPreparedStatementParams; private String characterSetMetadata; private String characterSetResultsOnServer; private Map charsetConverterMap; private long connectionId;//connectionId private String database;//database private DatabaseMetaData dbmd; private String host;//host private List hostList; private int hostListSize; private MysqlIO io;//MysqlIO private boolean isClientTzUTC; private boolean isClosed; private boolean isInGlobalTx; private boolean isRunningOnJDK13; private int isolationLevel;//事务隔离级别 private final Object mutex; private String myURL;//myURL private boolean needsPing; private int netBufferLength; private boolean noBackslashEscapes; private Map openStatements;//statment Map private LRUCache parsedCallableStatementCache;//存储过程缓存 private String password;//password private long perfMetricsHistBreakpoints[]; private int perfMetricsHistCounts[]; private Throwable pointOfOrigin; private int port;//port private boolean preferSlaveDuringFailover; protected Properties props; private long queriesIssuedFailedOver; private boolean readInfoMsg; private boolean readOnly;//readOnly protected LRUCache resultSetMetadataCache;//结果集缓存 private TimeZone serverTimezoneTZ;//服务器TimeZone private Map serverVariables; private long shortestQueryTimeMs; private Map statementsUsingMaxRows; private double totalQueryTimeMs; private boolean transactionsSupported; private Map typeMap; private boolean useAnsiQuotes; private String user;//user private boolean useServerPreparedStmts; private LRUCache serverSideStatementCheckCache; private LRUCache serverSideStatementCache; private Calendar sessionCalendar; private Calendar utcCalendar; private String origHostToConnectTo; private int origPortToConnectTo; private String origDatabaseToConnectTo; private String errorMessageEncoding; private boolean usePlatformCharsetConverters; private boolean hasTriedMasterFlag; private String statementComment; private boolean storesLowerCaseTableName; private List statementInterceptors; private boolean requiresEscapingEncoder; private boolean usingCachedConfig; private int autoIncrementIncrement; static { mapTransIsolationNameToValue = null; mapTransIsolationNameToValue = new HashMap(8); //五种事务隔离级别 mapTransIsolationNameToValue.put("READ-UNCOMMITED", Constants.integerValueOf(1)); mapTransIsolationNameToValue.put("READ-UNCOMMITTED", Constants.integerValueOf(1)); mapTransIsolationNameToValue.put("READ-COMMITTED", Constants.integerValueOf(2)); mapTransIsolationNameToValue.put("REPEATABLE-READ", Constants.integerValueOf(4)); mapTransIsolationNameToValue.put("SERIALIZABLE", Constants.integerValueOf(8)); boolean createdNamedTimer = false; try { Constructor ctr = (java.util.Timer.class).getConstructor(new Class[] { java.lang.String.class, Boolean.TYPE }); cancelTimer = (Timer)ctr.newInstance(new Object[] { "MySQL Statement Cancellation Timer", Boolean.TRUE }); createdNamedTimer = true; } catch(Throwable t) { createdNamedTimer = false; } if(!createdNamedTimer) cancelTimer = new Timer(true); if(Util.isJdbc4()) try { //获取JDBC4Connection的构造函数 JDBC_4_CONNECTION_CTOR = Class.forName("com.mysql.jdbc.JDBC4Connection").getConstructor(new Class[] { java.lang.String.class, Integer.TYPE, java.util.Properties.class, java.lang.String.class, java.lang.String.class }); } catch(ClassNotFoundException e) { throw new RuntimeException(e); } } //获取Connection protected static Connection getInstance(String hostToConnectTo, int portToConnectTo, Properties info, String databaseToConnectTo, String url) throws SQLException { //如果不是jdbc4则返回ConnectionImpl,否则为JDBC4Connection if(!Util.isJdbc4()) return new ConnectionImpl(hostToConnectTo, portToConnectTo, info, databaseToConnectTo, url); else return (Connection)Util.handleNewInstance(JDBC_4_CONNECTION_CTOR, new Object[] { hostToConnectTo, Constants.integerValueOf(portToConnectTo), info, databaseToConnectTo, url }, null); } }
先看ConnectionImpl,
//ConnectionImpl
protected ConnectionImpl(String hostToConnectTo, int portToConnectTo, Properties info, String databaseToConnectTo, String url) throws SQLException { autoCommit = true;//自动提交为true //所有变量先赋值为null,待不用时,垃圾回收器,回收变量 characterSetMetadata = null; characterSetResultsOnServer = null; charsetConverterMap = new HashMap(CharsetMapping.getNumberOfCharsetsConfigured()); connectionCreationTimeMillis = 0L; database = null; dbmd = null; executingFailoverReconnect = false; failedOver = false; hasIsolationLevels = false; hasQuotedIdentifiers = false; host = null; hostList = null; hostListSize = 0; indexToCharsetMapping = CharsetMapping.INDEX_TO_CHARSET; io = null; isClientTzUTC = false; isClosed = true; isInGlobalTx = false; isRunningOnJDK13 = false; isolationLevel = 2;//默认隔离级别为READ-COMMITTED isServerTzUTC = false; lastQueryFinishedTime = 0L; log = NULL_LOGGER; longestQueryTimeMs = 0L; lowerCaseTableNames = false; masterFailTimeMillis = 0L; maximumNumberTablesAccessed = 0L; maxRowsChanged = false; minimumNumberTablesAccessed = 9223372036854775807L; mutex = new Object();//互斥量 myURL = null; needsPing = false; netBufferLength = 16384; noBackslashEscapes = false; numberOfPreparedExecutes = 0L; numberOfPrepares = 0L; numberOfQueriesIssued = 0L; numberOfResultSetsCreated = 0L; oldHistBreakpoints = null; oldHistCounts = null; parserKnowsUnicode = false; password = null; port = 3306; preferSlaveDuringFailover = false; props = null; queriesIssuedFailedOver = 0L; readInfoMsg = false; readOnly = false;//默认读写 serverTimezoneTZ = null; serverVariables = null; shortestQueryTimeMs = 9223372036854775807L; totalQueryTimeMs = 0.0D; transactionsSupported = false; useAnsiQuotes = false; user = null; useServerPreparedStmts = false; errorMessageEncoding = "Cp1252"; hasTriedMasterFlag = false; statementComment = null; usingCachedConfig = false; autoIncrementIncrement = 0; charsetToNumBytesMap = new HashMap(); connectionCreationTimeMillis = System.currentTimeMillis(); pointOfOrigin = new Throwable(); origHostToConnectTo = hostToConnectTo; origPortToConnectTo = portToConnectTo; origDatabaseToConnectTo = databaseToConnectTo; try { (java.sql.Blob.class).getMethod("truncate", new Class[] { Long.TYPE }); isRunningOnJDK13 = false; } catch(NoSuchMethodException nsme) { isRunningOnJDK13 = true; } sessionCalendar = new GregorianCalendar(); utcCalendar = new GregorianCalendar(); utcCalendar.setTimeZone(TimeZone.getTimeZone("GMT")); log = LogFactory.getLogger(getLogger(), "MySQL", getExceptionInterceptor()); defaultTimeZone = Util.getDefaultTimeZone(); if("GMT".equalsIgnoreCase(defaultTimeZone.getID())) isClientTzUTC = true; else isClientTzUTC = false; openStatements = new HashMap(); serverVariables = new HashMap(); //初始化db信息,host,port,user,password等 hostList = new ArrayList(); if(hostToConnectTo == null) { host = "localhost"; hostList.add(host); } else if(hostToConnectTo.indexOf(',') != -1) { for(StringTokenizer hostTokenizer = new StringTokenizer(hostToConnectTo, ",", false); hostTokenizer.hasMoreTokens(); hostList.add(hostTokenizer.nextToken().trim())); } else { host = hostToConnectTo; hostList.add(host); } hostListSize = hostList.size(); port = portToConnectTo; if(databaseToConnectTo == null) databaseToConnectTo = ""; database = databaseToConnectTo; myURL = url; user = info.getProperty("user"); password = info.getProperty("password"); if(user == null || user.equals("")) user = ""; if(password == null) password = ""; props = info; //初始化驱动属性 initializeDriverProperties(info); try { //初始化数据库元数据信息 //private DatabaseMetaData dbmd; dbmd = getMetaData(false, false); //创建MysqlIO createNewIO(false); //初始化mysqlStatement拦截器 initializeStatementInterceptors(); //设置IO拦截器 io.setStatementInterceptors(statementInterceptors); } catch(SQLException ex) { //关闭mysqlIO cleanup(ex); throw ex; } catch(Exception ex) { cleanup(ex); StringBuffer mesg = new StringBuffer(128); if(!getParanoid()) { mesg.append("Cannot connect to MySQL server on "); mesg.append(host); mesg.append(":"); mesg.append(port); mesg.append(".\n\n"); mesg.append("Make sure that there is a MySQL server "); mesg.append("running on the machine/port you are trying "); mesg.append("to connect to and that the machine this software is running on "); mesg.append("is able to connect to this host/port (i.e. not firewalled). "); mesg.append("Also make sure that the server has not been started with the --skip-networking "); mesg.append("flag.\n\n"); } else { mesg.append("Unable to connect to database."); } SQLException sqlEx = SQLError.createSQLException(mesg.toString(), "08S01", getExceptionInterceptor()); sqlEx.initCause(ex); throw sqlEx; } }
//初始化驱动属性
initializeDriverProperties(info);
private void initializeDriverProperties(Properties info) throws SQLException { initializeProperties(info); String exceptionInterceptorClasses = getExceptionInterceptors(); if(exceptionInterceptorClasses != null && !"".equals(exceptionInterceptorClasses)) { exceptionInterceptor = new ExceptionInterceptorChain(exceptionInterceptorClasses); exceptionInterceptor.init(this, info); } usePlatformCharsetConverters = getUseJvmCharsetConverters(); log = LogFactory.getLogger(getLogger(), "MySQL", getExceptionInterceptor()); if(getProfileSql() || getUseUsageAdvisor()) eventSink = ProfilerEventHandlerFactory.getInstance(this); if(getCachePreparedStatements()) //创建PreparedStatement缓存 createPreparedStatementCaches(); if(getNoDatetimeStringSync() && getUseTimezone()) throw SQLError.createSQLException("Can't enable noDatetimeSync and useTimezone configuration properties at the same time", "01S00", getExceptionInterceptor()); if(getCacheCallableStatements()) //设置CallableStatement缓存 parsedCallableStatementCache = new LRUCache(getCallableStatementCacheSize()); if(getAllowMultiQueries()) setCacheResultSetMetadata(false); if(getCacheResultSetMetadata()) //设置结果集缓存 resultSetMetadataCache = new LRUCache(getMetadataCacheSize()); } //初始化属性 protected void initializeProperties(Properties info) throws SQLException { if(info != null) { String profileSqlLc = info.getProperty("profileSql"); if(profileSqlLc != null) info.put("profileSQL", profileSqlLc); Properties infoCopy = (Properties)info.clone(); infoCopy.remove("HOST"); infoCopy.remove("user"); infoCopy.remove("password"); infoCopy.remove("DBNAME"); infoCopy.remove("PORT"); infoCopy.remove("profileSql"); int numPropertiesToSet = PROPERTY_LIST.size(); for(int i = 0; i < numPropertiesToSet; i++) { Field propertyField = (Field)PROPERTY_LIST.get(i); try { ConnectionProperty propToSet = (ConnectionProperty)propertyField.get(this); propToSet.initializeFrom(infoCopy); } } postInitialization(); } }
//初始化数据库元数据信息
//private DatabaseMetaData dbmd;
dbmd = getMetaData(false, false);
private DatabaseMetaData getMetaData(boolean checkClosed, boolean checkForInfoSchema) throws SQLException { if(checkClosed) checkClosed(); return DatabaseMetaData.getInstance(this, database, checkForInfoSchema); }
//创建MysqlIO
createNewIO(false);
protected void createNewIO(boolean isForReconnect) throws SQLException { Object obj = mutex; JVM INSTR monitorenter ; Properties mergedProps; long queriesIssuedFailedOverCopy; mergedProps = exposeAsProperties(props); queriesIssuedFailedOverCopy = queriesIssuedFailedOver; queriesIssuedFailedOver = 0L; //对于Standyalone Sever情况 if(!getHighAvailability() && !failedOver) { boolean connectionGood = false; Exception connectionNotEstablishedBecause = null; int hostIndex = 0; if(getRoundRobinLoadBalance()) hostIndex = getNextRoundRobinHostIndex(getURL(), hostList); while(hostIndex < hostListSize) { if(hostIndex == 0) hasTriedMasterFlag = true; try { String newHostPortPair = (String)hostList.get(hostIndex); int newPort = 3306; String hostPortPair[] = NonRegisteringDriver.parseHostPortPair(newHostPortPair); String newHost = hostPortPair[0]; if(newHost == null || StringUtils.isEmptyOrWhitespaceOnly(newHost)) newHost = "localhost"; if(hostPortPair[1] != null) try { newPort = Integer.parseInt(hostPortPair[1]); } catch(NumberFormatException nfe) { throw SQLError.createSQLException("Illegal connection port value '" + hostPortPair[1] + "'", "01S00", getExceptionInterceptor()); } //创建MysqlIO io = new MysqlIO(newHost, newPort, mergedProps, getSocketFactoryClassName(), this, getSocketTimeout(), largeRowSizeThreshold.getValueAsInt()); //握手 io.doHandshake(user, password, database); //获取io的线程id connectionId = io.getThreadId(); isClosed = false; boolean oldAutoCommit = getAutoCommit();//AutoCommit int oldIsolationLevel = isolationLevel;//事务隔离级别 boolean oldReadOnly = isReadOnly();//ReadOnly String oldCatalog = getCatalog(); initializePropsFromServer(); if(isForReconnect) { setAutoCommit(oldAutoCommit); if(hasIsolationLevels) setTransactionIsolation(oldIsolationLevel); setCatalog(oldCatalog); } if(hostIndex != 0) { setFailedOverState(); queriesIssuedFailedOverCopy = 0L; } else { failedOver = false; queriesIssuedFailedOverCopy = 0L; if(hostListSize > 1) setReadOnlyInternal(false); else setReadOnlyInternal(oldReadOnly); } connectionGood = true; break; } catch(Exception EEE) { if(io != null) io.forceClose(); connectionNotEstablishedBecause = EEE; connectionGood = false; if(EEE instanceof SQLException) { SQLException sqlEx = (SQLException)EEE; String sqlState = sqlEx.getSQLState(); if(sqlState == null || !sqlState.equals("08S01")) throw sqlEx; } if(getRoundRobinLoadBalance()) { hostIndex = getNextRoundRobinHostIndex(getURL(), hostList) - 1; continue; } if(hostListSize - 1 == hostIndex) throw SQLError.createCommunicationsException(this, io == null ? 0L : io.getLastPacketSentTimeMs(), io == null ? 0L : io.getLastPacketReceivedTimeMs(), EEE, getExceptionInterceptor()); hostIndex++; } } if(!connectionGood) { SQLException chainedEx = SQLError.createSQLException(Messages.getString("Connection.UnableToConnect"), "08001", getExceptionInterceptor()); chainedEx.initCause(connectionNotEstablishedBecause); throw chainedEx; } } else { //对于负载均衡集群 double timeout = getInitialTimeout(); boolean connectionGood = false; Exception connectionException = null; int hostIndex = 0; if(getRoundRobinLoadBalance()) hostIndex = getNextRoundRobinHostIndex(getURL(), hostList); for(; hostIndex < hostListSize && !connectionGood; hostIndex++) { if(hostIndex == 0) hasTriedMasterFlag = true; if(preferSlaveDuringFailover && hostIndex == 0) hostIndex++; for(int attemptCount = 0; attemptCount < getMaxReconnects() && !connectionGood; attemptCount++) { try { if(io != null) io.forceClose(); String newHostPortPair = (String)hostList.get(hostIndex); int newPort = 3306; String hostPortPair[] = NonRegisteringDriver.parseHostPortPair(newHostPortPair); String newHost = hostPortPair[0]; if(newHost == null || StringUtils.isEmptyOrWhitespaceOnly(newHost)) newHost = "localhost"; if(hostPortPair[1] != null) try { newPort = Integer.parseInt(hostPortPair[1]); } catch(NumberFormatException nfe) { throw SQLError.createSQLException("Illegal connection port value '" + hostPortPair[1] + "'", "01S00", getExceptionInterceptor()); } //创建MysqlIO io = new MysqlIO(newHost, newPort, mergedProps, getSocketFactoryClassName(), this, getSocketTimeout(), largeRowSizeThreshold.getValueAsInt()); //握手 io.doHandshake(user, password, database); pingInternal(false, 0); //获取io的线程id connectionId = io.getThreadId(); isClosed = false; boolean oldAutoCommit = getAutoCommit();//AutoCommit int oldIsolationLevel = isolationLevel;//事务级别 boolean oldReadOnly = isReadOnly();//ReadOnly String oldCatalog = getCatalog(); initializePropsFromServer(); if(isForReconnect) { setAutoCommit(oldAutoCommit); if(hasIsolationLevels) setTransactionIsolation(oldIsolationLevel); setCatalog(oldCatalog); } connectionGood = true; if(hostIndex != 0) { setFailedOverState(); queriesIssuedFailedOverCopy = 0L; break; } failedOver = false; queriesIssuedFailedOverCopy = 0L; if(hostListSize > 1) setReadOnlyInternal(false); else setReadOnlyInternal(oldReadOnly); break; } catch(Exception EEE) { connectionException = EEE; } connectionGood = false; if(getRoundRobinLoadBalance()) hostIndex = getNextRoundRobinHostIndex(getURL(), hostList) - 1; if(connectionGood) break; if(attemptCount <= 0) continue; try { Thread.sleep((long)timeout * 1000L); } catch(InterruptedException IE) { } } } if(!connectionGood) { SQLException chainedEx = SQLError.createSQLException(Messages.getString("Connection.UnableToConnectWithRetries", new Object[] { new Integer(getMaxReconnects()) }), "08001", getExceptionInterceptor()); chainedEx.initCause(connectionException); throw chainedEx; } } if(getParanoid() && !getHighAvailability() && hostListSize <= 1) { password = null; user = null; } if(isForReconnect) { Iterator statementIter = openStatements.values().iterator(); Stack serverPreparedStatements = null; do { if(!statementIter.hasNext()) break; Object statementObj = statementIter.next(); if(statementObj instanceof ServerPreparedStatement) { if(serverPreparedStatements == null) serverPreparedStatements = new Stack(); serverPreparedStatements.add(statementObj); } } while(true); if(serverPreparedStatements != null) for(; !serverPreparedStatements.isEmpty(); ((ServerPreparedStatement)serverPreparedStatements.pop()).rePrepare()); } queriesIssuedFailedOver = queriesIssuedFailedOverCopy; break MISSING_BLOCK_LABEL_1241; Exception exception; exception; queriesIssuedFailedOver = queriesIssuedFailedOverCopy; throw exception; Exception exception1; exception1; throw exception1; }
//初始化mysqlStatement拦截器
initializeStatementInterceptors();
protected void initializeStatementInterceptors() throws SQLException { statementInterceptors = Util.loadExtensions(this, props, getStatementInterceptors(), "MysqlIo.BadStatementInterceptor", getExceptionInterceptor()); }
//设置IO拦截器
io.setStatementInterceptors(statementInterceptors);
//关闭mysqlIO
private void cleanup(Throwable whyCleanedUp) { try { if(io != null && !isClosed()) realClose(false, false, false, whyCleanedUp); else if(io != null) io.forceClose(); } catch(SQLException sqlEx) { } isClosed = true; }
从上面的分析,可以看出从DriverManager获取连接,实际上是事委托给com.mysql.jdbc.Driver,com.mysql.jdbc.Driver实际调用的是NonRegisteringDriver获取连接方法,首先分析url,如果url以jdbc:mysql:loadbalance://或jdbc:mysql:replication://开头,则调用负载均衡,集群的连接获取方法;如果是单机服务器,根据jdbc4的属性,创建相应的连接;如果不是jdbc4类型,则创建ConnectionImpl实例,初始化连接事务级别,db信息,autoCommit,readonly等属性,初始化驱动属性,创建PreparedStatement缓存,设置CallableStatement缓存,设置结果集缓存,初始化数据库元数据信息DatabaseMetaData,创建MysqlIO,初始化mysqlStatement拦截器,设置IO拦截器。
下面来看一下jdbc4连接:
//JDBC4Connection
public class JDBC4Connection extends ConnectionImpl { public JDBC4Connection(String hostToConnectTo, int portToConnectTo, Properties info, String databaseToConnectTo, String url) throws SQLException { super(hostToConnectTo, portToConnectTo, info, databaseToConnectTo, url); } private JDBC4ClientInfoProvider infoProvider; }
从上面可以看出JDBC4Connection是ConnectionImpl的包装。
至此mysql连接的获取讲完,下一篇,看一下集群及负载均衡的连接获取 。
//NonRegisteringDriver
public class NonRegisteringDriver implements Driver { //返回host,无返回localhost public String host(Properties props) { return props.getProperty("HOST", "localhost"); } public String database(Properties props) { return props.getProperty("DBNAME"); } //返回PORT,无返回3306 public int port(Properties props) { return Integer.parseInt(props.getProperty("PORT", "3306")); } private static final String REPLICATION_URL_PREFIX = "jdbc:mysql:replication://"; private static final String URL_PREFIX = "jdbc:mysql://"; private static final String MXJ_URL_PREFIX = "jdbc:mysql:mxj://"; private static final String LOADBALANCE_URL_PREFIX = "jdbc:mysql:loadbalance://"; public static final String DBNAME_PROPERTY_KEY = "DBNAME"; public static final boolean DEBUG = false; public static final int HOST_NAME_INDEX = 0; public static final String HOST_PROPERTY_KEY = "HOST"; public static final String PASSWORD_PROPERTY_KEY = "password"; public static final int PORT_NUMBER_INDEX = 1; public static final String PORT_PROPERTY_KEY = "PORT"; public static final String PROPERTIES_TRANSFORM_KEY = "propertiesTransform"; public static final boolean TRACE = false; public static final String USE_CONFIG_PROPERTY_KEY = "useConfigs"; public static final String USER_PROPERTY_KEY = "user"; }
//ConnectionImpl
public class ConnectionImpl extends ConnectionPropertiesImpl implements Connection { private static final String JDBC_LOCAL_CHARACTER_SET_RESULTS = "jdbc.local.character_set_results"; private static final Object CHARSET_CONVERTER_NOT_AVAILABLE_MARKER = new Object(); public static Map charsetMap; protected static final String DEFAULT_LOGGER_CLASS = "com.mysql.jdbc.log.StandardLogger"; private static final int HISTOGRAM_BUCKETS = 20; private static final String LOGGER_INSTANCE_NAME = "MySQL"; private static Map mapTransIsolationNameToValue; private static final Log NULL_LOGGER = new NullLogger("MySQL"); private static Map roundRobinStatsMap; private static final Map serverCollationByUrl = new HashMap(); private static final Map serverConfigByUrl = new HashMap(); private long queryTimeCount; private double queryTimeSum; private double queryTimeSumSquares; private double queryTimeMean; private static Timer cancelTimer; private List connectionLifecycleInterceptors; private static final Constructor JDBC_4_CONNECTION_CTOR; private static final int DEFAULT_RESULT_SET_TYPE = 1003; private static final int DEFAULT_RESULT_SET_CONCURRENCY = 1007; private boolean autoCommit; private Map cachedPreparedStatementParams; private String characterSetMetadata; private String characterSetResultsOnServer; private Map charsetConverterMap; private Map charsetToNumBytesMap; private long connectionCreationTimeMillis; private long connectionId; private String database; private DatabaseMetaData dbmd; private TimeZone defaultTimeZone; private ProfilerEventHandler eventSink; private boolean executingFailoverReconnect; private boolean failedOver; private Throwable forceClosedReason; private Throwable forcedClosedLocation; private boolean hasIsolationLevels; private boolean hasQuotedIdentifiers; private String host; private List hostList; private int hostListSize; private String indexToCharsetMapping[]; private MysqlIO io; private boolean isClientTzUTC; private boolean isClosed; private boolean isInGlobalTx; private boolean isRunningOnJDK13; private int isolationLevel; private boolean isServerTzUTC; private long lastQueryFinishedTime; private Log log; private long longestQueryTimeMs; private boolean lowerCaseTableNames; private long masterFailTimeMillis; private long maximumNumberTablesAccessed; private boolean maxRowsChanged; private long metricsLastReportedMs; private long minimumNumberTablesAccessed; private final Object mutex; private String myURL; private boolean needsPing; private int netBufferLength; private boolean noBackslashEscapes; private long numberOfPreparedExecutes; private long numberOfPrepares; private long numberOfQueriesIssued; private long numberOfResultSetsCreated; private long numTablesMetricsHistBreakpoints[]; private int numTablesMetricsHistCounts[]; private long oldHistBreakpoints[]; private int oldHistCounts[]; private Map openStatements; private LRUCache parsedCallableStatementCache; private boolean parserKnowsUnicode; private String password; private long perfMetricsHistBreakpoints[]; private int perfMetricsHistCounts[]; private Throwable pointOfOrigin; private int port; private boolean preferSlaveDuringFailover; protected Properties props; private long queriesIssuedFailedOver; private boolean readInfoMsg; private boolean readOnly; protected LRUCache resultSetMetadataCache; private TimeZone serverTimezoneTZ; private Map serverVariables; private long shortestQueryTimeMs; private Map statementsUsingMaxRows; private double totalQueryTimeMs; private boolean transactionsSupported; private Map typeMap; private boolean useAnsiQuotes; private String user; private boolean useServerPreparedStmts; private LRUCache serverSideStatementCheckCache; private LRUCache serverSideStatementCache; private Calendar sessionCalendar; private Calendar utcCalendar; private String origHostToConnectTo; private int origPortToConnectTo; private String origDatabaseToConnectTo; private String errorMessageEncoding; private boolean usePlatformCharsetConverters; private boolean hasTriedMasterFlag; private String statementComment; private boolean storesLowerCaseTableName; private List statementInterceptors; private boolean requiresEscapingEncoder; private boolean usingCachedConfig; private int autoIncrementIncrement; private ExceptionInterceptor exceptionInterceptor; }
//DatabaseMetaData
public class DatabaseMetaData implements java.sql.DatabaseMetaData { private static String mysqlKeywordsThatArentSQL92; protected static final int MAX_IDENTIFIER_LENGTH = 64; private static final int DEFERRABILITY = 13; private static final int DELETE_RULE = 10; private static final int FK_NAME = 11; private static final int FKCOLUMN_NAME = 7; private static final int FKTABLE_CAT = 4; private static final int FKTABLE_NAME = 6; private static final int FKTABLE_SCHEM = 5; private static final int KEY_SEQ = 8; private static final int PK_NAME = 12; private static final int PKCOLUMN_NAME = 3; private static final int PKTABLE_CAT = 0; private static final int PKTABLE_NAME = 2; private static final int PKTABLE_SCHEM = 1; private static final String SUPPORTS_FK = "SUPPORTS_FK"; private static final byte TABLE_AS_BYTES[] = "TABLE".getBytes(); private static final byte SYSTEM_TABLE_AS_BYTES[] = "SYSTEM TABLE".getBytes(); private static final int UPDATE_RULE = 9; private static final byte VIEW_AS_BYTES[] = "VIEW".getBytes(); private static final Constructor JDBC_4_DBMD_SHOW_CTOR; private static final Constructor JDBC_4_DBMD_IS_CTOR; protected ConnectionImpl conn; protected String database; protected String quotedId; private ExceptionInterceptor exceptionInterceptor; static { if(Util.isJdbc4()) { try { JDBC_4_DBMD_SHOW_CTOR = Class.forName("com.mysql.jdbc.JDBC4DatabaseMetaData").getConstructor(new Class[] { com.mysql.jdbc.ConnectionImpl.class, java.lang.String.class }); JDBC_4_DBMD_IS_CTOR = Class.forName("com.mysql.jdbc.JDBC4DatabaseMetaDataUsingInfoSchema").getConstructor(new Class[] { com.mysql.jdbc.ConnectionImpl.class, java.lang.String.class }); } catch(SecurityException e) { throw new RuntimeException(e); } catch(NoSuchMethodException e) { throw new RuntimeException(e); } catch(ClassNotFoundException e) { throw new RuntimeException(e); } } else { JDBC_4_DBMD_IS_CTOR = null; JDBC_4_DBMD_SHOW_CTOR = null; } //mysql关键字 String allMySQLKeywords[] = { "ACCESSIBLE", "ADD", "ALL", "ALTER", "ANALYZE", "AND", "AS", "ASC", "ASENSITIVE", "BEFORE", "BETWEEN", "BIGINT", "BINARY", "BLOB", "BOTH", "BY", "CALL", "CASCADE", "CASE", "CHANGE", "CHAR", "CHARACTER", "CHECK", "COLLATE", "COLUMN", "CONDITION", "CONNECTION", "CONSTRAINT", "CONTINUE", "CONVERT", "CREATE", "CROSS", "CURRENT_DATE", "CURRENT_TIME", "CURRENT_TIMESTAMP", "CURRENT_USER", "CURSOR", "DATABASE", "DATABASES", "DAY_HOUR", "DAY_MICROSECOND", "DAY_MINUTE", "DAY_SECOND", "DEC", "DECIMAL", "DECLARE", "DEFAULT", "DELAYED", "DELETE", "DESC", "DESCRIBE", "DETERMINISTIC", "DISTINCT", "DISTINCTROW", "DIV", "DOUBLE", "DROP", "DUAL", "EACH", "ELSE", "ELSEIF", "ENCLOSED", "ESCAPED", "EXISTS", "EXIT", "EXPLAIN", "FALSE", "FETCH", "FLOAT", "FLOAT4", "FLOAT8", "FOR", "FORCE", "FOREIGN", "FROM", "FULLTEXT", "GRANT", "GROUP", "HAVING", "HIGH_PRIORITY", "HOUR_MICROSECOND", "HOUR_MINUTE", "HOUR_SECOND", "IF", "IGNORE", "IN", "INDEX", "INFILE", "INNER", "INOUT", "INSENSITIVE", "INSERT", "INT", "INT1", "INT2", "INT3", "INT4", "INT8", "INTEGER", "INTERVAL", "INTO", "IS", "ITERATE", "JOIN", "KEY", "KEYS", "KILL", "LEADING", "LEAVE", "LEFT", "LIKE", "LIMIT", "LINEAR", "LINES", "LOAD", "LOCALTIME", "LOCALTIMESTAMP", "LOCK", "LONG", "LONGBLOB", "LONGTEXT", "LOOP", "LOW_PRIORITY", "MATCH", "MEDIUMBLOB", "MEDIUMINT", "MEDIUMTEXT", "MIDDLEINT", "MINUTE_MICROSECOND", "MINUTE_SECOND", "MOD", "MODIFIES", "NATURAL", "NOT", "NO_WRITE_TO_BINLOG", "NULL", "NUMERIC", "ON", "OPTIMIZE", "OPTION", "OPTIONALLY", "OR", "ORDER", "OUT", "OUTER", "OUTFILE", "PRECISION", "PRIMARY", "PROCEDURE", "PURGE", "RANGE", "READ", "READS", "READ_ONLY", "READ_WRITE", "REAL", "REFERENCES", "REGEXP", "RELEASE", "RENAME", "REPEAT", "REPLACE", "REQUIRE", "RESTRICT", "RETURN", "REVOKE", "RIGHT", "RLIKE", "SCHEMA", "SCHEMAS", "SECOND_MICROSECOND", "SELECT", "SENSITIVE", "SEPARATOR", "SET", "SHOW", "SMALLINT", "SPATIAL", "SPECIFIC", "SQL", "SQLEXCEPTION", "SQLSTATE", "SQLWARNING", "SQL_BIG_RESULT", "SQL_CALC_FOUND_ROWS", "SQL_SMALL_RESULT", "SSL", "STARTING", "STRAIGHT_JOIN", "TABLE", "TERMINATED", "THEN", "TINYBLOB", "TINYINT", "TINYTEXT", "TO", "TRAILING", "TRIGGER", "TRUE", "UNDO", "UNION", "UNIQUE", "UNLOCK", "UNSIGNED", "UPDATE", "USAGE", "USE", "USING", "UTC_DATE", "UTC_TIME", "UTC_TIMESTAMP", "VALUES", "VARBINARY", "VARCHAR", "VARCHARACTER", "VARYING", "WHEN", "WHERE", "WHILE", "WITH", "WRITE", "X509", "XOR", "YEAR_MONTH", "ZEROFILL" }; //sql92关键字 String sql92Keywords[] = { "ABSOLUTE", "EXEC", "OVERLAPS", "ACTION", "EXECUTE", "PAD", "ADA", "EXISTS", "PARTIAL", "ADD", "EXTERNAL", "PASCAL", "ALL", "EXTRACT", "POSITION", "ALLOCATE", "FALSE", "PRECISION", "ALTER", "FETCH", "PREPARE", "AND", "FIRST", "PRESERVE", "ANY", "FLOAT", "PRIMARY", "ARE", "FOR", "PRIOR", "AS", "FOREIGN", "PRIVILEGES", "ASC", "FORTRAN", "PROCEDURE", "ASSERTION", "FOUND", "PUBLIC", "AT", "FROM", "READ", "AUTHORIZATION", "FULL", "REAL", "AVG", "GET", "REFERENCES", "BEGIN", "GLOBAL", "RELATIVE", "BETWEEN", "GO", "RESTRICT", "BIT", "GOTO", "REVOKE", "BIT_LENGTH", "GRANT", "RIGHT", "BOTH", "GROUP", "ROLLBACK", "BY", "HAVING", "ROWS", "CASCADE", "HOUR", "SCHEMA", "CASCADED", "IDENTITY", "SCROLL", "CASE", "IMMEDIATE", "SECOND", "CAST", "IN", "SECTION", "CATALOG", "INCLUDE", "SELECT", "CHAR", "INDEX", "SESSION", "CHAR_LENGTH", "INDICATOR", "SESSION_USER", "CHARACTER", "INITIALLY", "SET", "CHARACTER_LENGTH", "INNER", "SIZE", "CHECK", "INPUT", "SMALLINT", "CLOSE", "INSENSITIVE", "SOME", "COALESCE", "INSERT", "SPACE", "COLLATE", "INT", "SQL", "COLLATION", "INTEGER", "SQLCA", "COLUMN", "INTERSECT", "SQLCODE", "COMMIT", "INTERVAL", "SQLERROR", "CONNECT", "INTO", "SQLSTATE", "CONNECTION", "IS", "SQLWARNING", "CONSTRAINT", "ISOLATION", "SUBSTRING", "CONSTRAINTS", "JOIN", "SUM", "CONTINUE", "KEY", "SYSTEM_USER", "CONVERT", "LANGUAGE", "TABLE", "CORRESPONDING", "LAST", "TEMPORARY", "COUNT", "LEADING", "THEN", "CREATE", "LEFT", "TIME", "CROSS", "LEVEL", "TIMESTAMP", "CURRENT", "LIKE", "TIMEZONE_HOUR", "CURRENT_DATE", "LOCAL", "TIMEZONE_MINUTE", "CURRENT_TIME", "LOWER", "TO", "CURRENT_TIMESTAMP", "MATCH", "TRAILING", "CURRENT_USER", "MAX", "TRANSACTION", "CURSOR", "MIN", "TRANSLATE", "DATE", "MINUTE", "TRANSLATION", "DAY", "MODULE", "TRIM", "DEALLOCATE", "MONTH", "TRUE", "DEC", "NAMES", "UNION", "DECIMAL", "NATIONAL", "UNIQUE", "DECLARE", "NATURAL", "UNKNOWN", "DEFAULT", "NCHAR", "UPDATE", "DEFERRABLE", "NEXT", "UPPER", "DEFERRED", "NO", "USAGE", "DELETE", "NONE", "USER", "DESC", "NOT", "USING", "DESCRIBE", "NULL", "VALUE", "DESCRIPTOR", "NULLIF", "VALUES", "DIAGNOSTICS", "NUMERIC", "VARCHAR", "DISCONNECT", "OCTET_LENGTH", "VARYING", "DISTINCT", "OF", "VIEW", "DOMAIN", "ON", "WHEN", "DOUBLE", "ONLY", "WHENEVER", "DROP", "OPEN", "WHERE", "ELSE", "OPTION", "WITH", "END", "OR", "WORK", "END-EXEC", "ORDER", "WRITE", "ESCAPE", "OUTER", "YEAR", "EXCEPT", "OUTPUT", "ZONE", "EXCEPTION" }; TreeMap mySQLKeywordMap = new TreeMap(); for(int i = 0; i < allMySQLKeywords.length; i++) mySQLKeywordMap.put(allMySQLKeywords[i], null); HashMap sql92KeywordMap = new HashMap(sql92Keywords.length); for(int i = 0; i < sql92Keywords.length; i++) sql92KeywordMap.put(sql92Keywords[i], null); Iterator it; for(it = sql92KeywordMap.keySet().iterator(); it.hasNext(); mySQLKeywordMap.remove(it.next())); StringBuffer keywordBuf = new StringBuffer(); it = mySQLKeywordMap.keySet().iterator(); if(it.hasNext()) keywordBuf.append(it.next().toString()); for(; it.hasNext(); keywordBuf.append(it.next().toString())) keywordBuf.append(","); mysqlKeywordsThatArentSQL92 = keywordBuf.toString(); }
//Util
public class Util { public static boolean isJdbc4() { return isJdbc4; } protected static Method systemNanoTimeMethod; private static Method CAST_METHOD; private static final TimeZone DEFAULT_TIMEZONE = TimeZone.getDefault(); private static Util enclosingInstance = new Util(); private static boolean isJdbc4 = false; private static boolean isColdFusion = false; static { try { systemNanoTimeMethod = (java.lang.System.class).getMethod("nanoTime", null); } catch(SecurityException e) { systemNanoTimeMethod = null; } catch(NoSuchMethodException e) { systemNanoTimeMethod = null; } try { CAST_METHOD = (java.lang.Class.class).getMethod("cast", new Class[] { java.lang.Object.class }); } catch(Throwable t) { } try { //如果加载java.sql.NClob正常,则isJdbc4为true Class.forName("java.sql.NClob"); isJdbc4 = true; } catch(Throwable t) { isJdbc4 = false; } String loadedFrom = stackTraceToString(new Throwable()); if(loadedFrom != null) isColdFusion = loadedFrom.indexOf("coldfusion") != -1; else isColdFusion = false; } //构造className public static Object getInstance(String className, Class argTypes[], Object args[], ExceptionInterceptor exceptionInterceptor) throws SQLException { return handleNewInstance(Class.forName(className).getConstructor(argTypes), args, exceptionInterceptor); SecurityException e; e; throw SQLError.createSQLException("Can't instantiate required class", "S1000", e, exceptionInterceptor); e; throw SQLError.createSQLException("Can't instantiate required class", "S1000", e, exceptionInterceptor); e; throw SQLError.createSQLException("Can't instantiate required class", "S1000", e, exceptionInterceptor); } //根据Constructor,args创建,构建object public static final Object handleNewInstance(Constructor ctor, Object args[], ExceptionInterceptor exceptionInterceptor) throws SQLException { return ctor.newInstance(args); IllegalArgumentException e; e; throw SQLError.createSQLException("Can't instantiate required class", "S1000", e, exceptionInterceptor); e; throw SQLError.createSQLException("Can't instantiate required class", "S1000", e, exceptionInterceptor); e; throw SQLError.createSQLException("Can't instantiate required class", "S1000", e, exceptionInterceptor); e; Throwable target = e.getTargetException(); if(target instanceof SQLException) throw (SQLException)target; if(target instanceof ExceptionInInitializerError) target = ((ExceptionInInitializerError)target).getException(); throw SQLError.createSQLException(target.toString(), "S1000", exceptionInterceptor); } public static boolean interfaceExists(String hostname) { Class networkInterfaceClass = Class.forName("java.net.NetworkInterface"); return networkInterfaceClass.getMethod("getByName", null).invoke(networkInterfaceClass, new Object[] { hostname }) != null; Throwable t; t; return false; } public static Object cast(Object invokeOn, Object toCast) { if(CAST_METHOD == null) break MISSING_BLOCK_LABEL_25; return CAST_METHOD.invoke(invokeOn, new Object[] { toCast }); Throwable t; t; return null; return null; } }
发表评论
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Mysql PreparedStatement 批处理
2016-12-06 18:09 1388JDBC驱动初始化-Mysql:http://donald-d ... -
MySQL ServerPreparedStatement查询
2016-12-06 14:42 1300JDBC驱动初始化-Mysql:http://donald-d ... -
MysqlSQL PreparedStatement的查询
2016-12-06 11:40 2037JDBC驱动初始化-Mysql:http://donald-d ... -
Mysql预编译SQL
2016-12-05 19:06 1173JDBC驱动初始化-Mysql:http://donald-d ... -
ConnectionImp创建MysqlIO
2016-12-05 19:01 1028JDBC驱动初始化-Mysql:http://donald-d ... -
Mysql主从复制读写分离连接的获取
2016-12-01 08:43 1172JDBC驱动初始化-Mysql:http://donald-d ... -
Mysql负载均衡连接的获取
2016-12-01 08:38 1337Java动态代理:http://www.cnblogs.com ... -
JDBC驱动初始化-Mysql
2016-11-30 12:41 3056JDBC驱动初始化-Mysql:http://donald-d ... -
mysql 存储过程
2016-07-17 14:49 907存储过程基础:http://sishuok.com/forum ... -
java.sql.Date,java.util.Date,java.sql.Timestamp的区别
2016-07-17 11:50 884java.sql.Date,jdbc映射数据库中的date类型 ... -
JDBC PreparedStatement 的用法
2016-07-15 17:27 899import java.sql.Connection; im ...
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下面将详细介绍如何使用JDBC连接Hive和Impala。 1. **JDBC连接Hive** Hive提供了一个名为Hive JDBC的驱动,它允许外部应用程序通过JDBC协议与Hive服务通信。要建立JDBC连接到Hive,你需要以下步骤: - **获取...
在IT行业中,数据库连接管理是应用系统性能优化的关键环节之一,而JDBC连接池就是解决这一问题的有效工具。本文将详细讲解JDBC连接池的工作原理、配置方法以及如何通过优化来提升连接速度。 JDBC(Java Database ...
### JDBC连接数据库各种数据库参数详解 #### 一、Oracle8/8i/9i数据库(thin模式) 在Java中通过JDBC访问Oracle数据库时,通常采用thin驱动方式。thin驱动是一种纯Java驱动,无需依赖任何非Java代码即可完成与...
1. **JDBC连接的基本步骤** - 加载数据库驱动:使用`Class.forName()`方法加载对应的数据库驱动。 - 获取数据库连接:通过`DriverManager.getConnection()`方法,传入数据库URL、用户名和密码创建连接。 - 创建...
JDBC连接数据库 连接数据库通常分为以下步骤: 1. **加载驱动**:使用`Class.forName()`方法加载对应的数据库驱动。 2. **获取连接**:通过`DriverManager.getConnection()`方法,传入数据库URL、用户名和密码来...
总结来说,"Jdbc连接postgresql数据库(源码+jar包)"资源提供了使用Java JDBC连接到PostgreSQL数据库的实例,涵盖了从加载驱动到执行SQL的基本流程,对于学习和实践非常有帮助。通过学习和理解这些代码,开发者能够...
MySQL JDBC 连接器,全称...总之,MySQL JDBC连接器是Java开发者不可或缺的工具,它使得我们可以方便地在Java应用中集成MySQL数据库,实现各种复杂的数据库操作,同时也需要我们关注其版本特性、性能优化以及安全实践。
标题中的“jdbc连接不同数据库方法”指的是使用Java Database Connectivity (JDBC) API来与不同的数据库进行交互的方法。JDBC是Java平台中用于访问数据库的标准Java API,它允许开发者执行SQL语句并处理结果。 在...
**JDBC连接大全** 在Java编程中,JDBC(Java Database Connectivity)是Java语言与数据库交互的标准接口,它使得开发者可以使用Java代码来操作数据库。本篇内容将深入探讨JDBC连接的各个方面,旨在为你提供全面的...
### JDBC连接数据库步骤详解 #### 一、简介 在Java开发中,经常需要与数据库进行交互,例如查询数据、更新数据等操作。为了方便开发者进行这些操作,Sun公司推出了一套标准的Java访问数据库的API——Java Database...
本案例将探讨如何使用JDBC连接MySQL数据库,并通过实际的代码示例讲解整个过程。我们将涉及以下知识点: 1. **JDBC驱动注册**: 在Java中,连接MySQL数据库首先需要加载并注册JDBC驱动。MySQL的JDBC驱动类是`...
在Java开发中,数据库操作是不可或缺的一部分,而JDBC连接池是提高数据库访问效率、优化系统资源使用的重要技术。本文将深入探讨JDBC连接池的概念、工作原理,并以"通用basedao"模板为例,讲解如何在实际项目中应用...
"自定义高并发jdbc连接池"是一个专为处理大量并发请求而设计的解决方案,它允许应用程序高效地管理和复用数据库连接,从而减少数据库连接创建与释放的开销,提高系统的整体性能。 JDBC(Java Database Connectivity...
**JDBC连接数据库详解** Java Database Connectivity (JDBC) 是Java平台中用于与关系型数据库交互的一组标准API。在Spring框架中,JDBC被用来简化数据库操作,提供了更高级别的抽象,使得开发者能更方便地处理数据...
在获取JDBC连接的场景中,我们可以创建一个抽象的`DatabaseConnectionFactory`,它声明一个返回`Connection`的方法。然后针对不同的数据库(如MySQL、Oracle等),我们创建各自的实现类,覆盖这个方法以返回相应的...
对于初学者来说,理解JDBC连接数据库的基本步骤至关重要。以下是详细解释这些步骤的知识点: 1. 加载JDBC驱动程序: 在连接数据库之前,首先需要在Java虚拟机(JVM)中加载对应的数据库驱动程序。这一步是通过使用...
本实例提供了完美的Java JDBC连接池配置,适用于Oracle、MySQL和SQL Server等主流数据库,允许开发者轻松地在不同数据库之间切换方言。 首先,让我们了解什么是JDBC连接池。JDBC(Java Database Connectivity)是...