mybatis3源码核心类1--Configuration

最近没什么事，花了一周的时间把mybatis源码看完了，现自我总结一下，尽可能的用一句话总结，方便自己理解和回顾。


出名的框架几乎都是从初始化配置文件开始的，mybatis也一样。

mybatis的配置文件是通过工具类XMLConfigBuilder，XMLMapperBuilder，XMLStatementBuilder解析后都存在Configuration中

private void parseConfiguration(XNode root) {
    try {
      propertiesElement(root.evalNode("properties")); //issue #117 read properties first
      typeAliasesElement(root.evalNode("typeAliases"));
      pluginElement(root.evalNode("plugins"));
      objectFactoryElement(root.evalNode("objectFactory"));
      objectWrapperFactoryElement(root.evalNode("objectWrapperFactory"));
      settingsElement(root.evalNode("settings"));
      environmentsElement(root.evalNode("environments")); // read it after objectFactory and objectWrapperFactory issue #631
      databaseIdProviderElement(root.evalNode("databaseIdProvider"));
      typeHandlerElement(root.evalNode("typeHandlers"));
      mapperElement(root.evalNode("mappers"));
    } catch (Exception e) {
      throw new BuilderException("Error parsing SQL Mapper Configuration. Cause: " + e, e);
    }
  }

public class Configuration {

  protected Environment environment;

  protected boolean safeRowBoundsEnabled = false;
  protected boolean safeResultHandlerEnabled = true;
  protected boolean mapUnderscoreToCamelCase = false;
  protected boolean aggressiveLazyLoading = true;
  protected boolean multipleResultSetsEnabled = true;
  protected boolean useGeneratedKeys = false;
  protected boolean useColumnLabel = true;
  //二级缓存开关，直接决定sqlSession是否启用CachingExecutor
  protected boolean cacheEnabled = true;
  protected boolean callSettersOnNulls = false;

  protected String logPrefix;
  protected Class <? extends Log> logImpl;
  //一级缓存的默认作用域
  protected LocalCacheScope localCacheScope = LocalCacheScope.SESSION;
  protected JdbcType jdbcTypeForNull = JdbcType.OTHER;
  protected Set<String> lazyLoadTriggerMethods = new HashSet<String>(Arrays.asList(new String[] { "equals", "clone", "hashCode", "toString" }));
  protected Integer defaultStatementTimeout;
  protected Integer defaultFetchSize;
  protected ExecutorType defaultExecutorType = ExecutorType.SIMPLE;
  protected AutoMappingBehavior autoMappingBehavior = AutoMappingBehavior.PARTIAL;
  //config配置文件Properties标签的数据存储  -----全局属性配置对象
  protected Properties variables = new Properties();
  protected ReflectorFactory reflectorFactory = new DefaultReflectorFactory();
  //config配置文件objectFactory标签的数据存储
  protected ObjectFactory objectFactory = new DefaultObjectFactory();
  protected ObjectWrapperFactory objectWrapperFactory = new DefaultObjectWrapperFactory();
  //maper接口的存储容器， mybatis访问数据库的动态代理接口，MapperProxyFactory 是经典的C/S架构客户端同步访问实现
  protected MapperRegistry mapperRegistry = new MapperRegistry(this);

  protected boolean lazyLoadingEnabled = false;
  protected ProxyFactory proxyFactory = new JavassistProxyFactory(); // #224 Using internal Javassist instead of OGNL
  //数据源 id
  protected String databaseId;
  /**
   * Configuration factory class.
   * Used to create Configuration for loading deserialized unread properties.
   *
   * @see <a href='https://code.google.com/p/mybatis/issues/detail?id=300'>Issue 300</a> (google code)
   */
  protected Class<?> configurationFactory;
 //插件，可以在核心业务逻辑处理类“statementHandler”中增加sql解析，sql路由等等功能
  protected final InterceptorChain interceptorChain = new InterceptorChain();
  //config配置文件typeHandler标签的数据容器
  protected final TypeHandlerRegistry typeHandlerRegistry = new TypeHandlerRegistry();
  //config配置文件typeAlias标签的数据容器  ---别名对应容器
  protected final TypeAliasRegistry typeAliasRegistry = new TypeAliasRegistry();
  //language容器
  protected final LanguageDriverRegistry languageRegistry = new LanguageDriverRegistry();
  //mapper配置文件的数据容器
  protected final Map<String, MappedStatement> mappedStatements = new StrictMap<MappedStatement>("Mapped Statements collection");
  //缓存容器
  protected final Map<String, Cache> caches = new StrictMap<Cache>("Caches collection");
  //resultMap容器，思考：抛弃ORM设计思想，  还可以通过JDBC的ResultSet相关方法组装成map对象返回，不需要resultSetHandler.<E>handleResultSets(statement)。
  protected final Map<String, ResultMap> resultMaps = new StrictMap<ResultMap>("Result Maps collection");
  //输入参数类型容器
  protected final Map<String, ParameterMap> parameterMaps = new StrictMap<ParameterMap>("Parameter Maps collection");
  //主键生成器容器
  protected final Map<String, KeyGenerator> keyGenerators = new StrictMap<KeyGenerator>("Key Generators collection");

  protected final Set<String> loadedResources = new HashSet<String>();
  protected final Map<String, XNode> sqlFragments = new StrictMap<XNode>("XML fragments parsed from previous mappers");
  //异常数据容器
  protected final Collection<XMLStatementBuilder> incompleteStatements = new LinkedList<XMLStatementBuilder>();
  //异常数据容器
  protected final Collection<CacheRefResolver> incompleteCacheRefs = new LinkedList<CacheRefResolver>();
  //异常数据容器
  protected final Collection<ResultMapResolver> incompleteResultMaps = new LinkedList<ResultMapResolver>();
  //异常数据容器
  protected final Collection<MethodResolver> incompleteMethods = new LinkedList<MethodResolver>();

  /*
   * A map holds cache-ref relationship. The key is the namespace that
   * references a cache bound to another namespace and the value is the
   * namespace which the actual cache is bound to.
   */
  protected final Map<String, String> cacheRefMap = new HashMap<String, String>();

评论

1 楼 jiang2011jiang 2016-08-18