tomcat连接池配置 --详解

context.xml中的配置

 

<Context path="/DBTest" docBase="DBTest"
       debug="5" reloadable="true" crossContext="true">
<!—注意到这里的DBTest了吧，这就是要求大家建立DBTest目录的原因。--> 

 <Logger className="org.apache.catalina.logger.FileLogger"
            prefix="localhost_DBTest_log." suffix=".txt"
            timestamp="true"/> 

 <Resource name="jdbc/TestDB"
              auth="Container"
              type="javax.sql.DataSource"/>
 <ResourceParams name="jdbc/TestDB">
   <parameter>
     <name>factory</name>
     <value>org.apache.commons.dbcp.BasicDataSourceFactory</value>
   </parameter> 

   <!-- Maximum number of dB connections in pool. Make sure you
        configure your mysqld max_connections large enough to handle
        all of your db connections. Set to 0 for no limit.
        -->
   <parameter>
     <name>maxActive</name>
     <value>100</value>
   </parameter> 

   <!-- Maximum number of idle dB connections to retain in pool.
        Set to 0 for no limit.
        -->
   <parameter>
     <name>maxIdle</name>
     <value>30</value>
   </parameter> 

   <!-- Maximum time to wait for a dB connection to become available
        in ms, in this example 10 seconds. An Exception is thrown if
        this timeout is exceeded.  Set to -1 to wait indefinitely.
        -->
   <parameter>
     <name>maxWait</name>
     <value>10000</value>
   </parameter> 

   <!-- MySQL dB username and password for dB connections  -->
   <parameter>
    <name>username</name>
    <value>javauser</value>
<!—数据库用户名--> 

   </parameter>
   <parameter>
    <name>password</name>
    <value>javadude</value>
<!—数据库密码-->
   </parameter>
   <!-- Class name for the old mm.mysql JDBC driver - uncomment this entry and comment next
        if you want to use this driver - we recommend using Connector/J though
   <parameter>
      <name>driverClassName</name>
      <value>org.gjt.mm.mysql.Driver</value>
</parameter>
这里面是被注释的，因为以前连接mysql是这样连接的，现在建议用下面的方法，自己可以看到。
    -->
   
   <!-- Class name for the official MySQL Connector/J driver -->
   <parameter>
      <name>driverClassName</name>
      <value>com.mysql.jdbc.Driver</value>
   </parameter>
   
   <!-- The JDBC connection url for connecting to your MySQL dB.
        The autoReconnect=true argument to the url makes sure that the
        mm.mysql JDBC Driver will automatically reconnect if mysqld closed the
        connection.  mysqld by default closes idle connections after 8 hours.
        -->
   <parameter>
     <name>url</name>
     <value>jdbc:mysql://localhost:3306/javatest?autoReconnect=true</value>
<!--这是数据库的地址，也可以不要这么繁琐，改为
jdbc:mysql://localhost/javatest即可,javatest为数据库名-->
   </parameter>
 </ResourceParams>
</Context>

 

2. web.xml 中的配置

 

<?xml version="1.0" encoding="ISO-8859-1"?>
<web-app xmlns="http://java.sun.com/xml/ns/j2ee"
   xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
   xsi:schemaLocation="http://java.sun.com/xml/ns/j2ee
http://java.sun.com/xml/ns/j2ee/web-app_2_4.xsd"  version="2.4">
 <description>MySQL Test App</description>
 <resource-ref>
     <description>DB Connection</description>
     <res-ref-name>jdbc/TestDB</res-ref-name>
     <res-type>javax.sql.DataSource</res-type>
     <res-auth>Container</res-auth>
 </resource-ref>
</web-app>

3. java中使用的代码

 

 

try
{
Context initCtx=new InitialContext();
DataSource ds = (DataSource)initCtx.lookup("java:comp/env/jdbc/TestDB");
Connection conn=ds.getConnection();
out.println("data from database:<br>");
Statement stmt=conn.createStatement();
ResultSet rs =stmt.executeQuery("select id, foo, bar from testdata");
while(rs.next())
{
out.println(rs.getInt("id"));
out.println(rs.getString("foo"));
out.println(rs.getString("bar"));
}
rs.close();
stmt.close();
}
catch(Exception e)
{
e.printStackTrace();
}