tomcate連接池

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context.xml 中的配置

 

<Context path="/DBTest" docBase="DBTest" 

        debug="5" reloadable="true" crossContext="true"> 

  <! —注意到這裏的 DBTest 了吧，這就是要求大家建立 DBTest 目錄的原因。 -->  

  

  <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> 

  <! —數據庫用戶名 -->  

  

    </parameter> 

    <parameter> 

     <name>password</name> 

     <value>javadude</value> 

  <! —數據庫密碼 --> 

    </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> 

  這裏面是被註釋的，因爲以前連接 mysql 是這樣連接的，現在建議用下面的方法，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> 

  <!-- 這是數據庫的地址，也可以不要這麼繁瑣，改爲  

  jdbc:mysql://localhost/javatest 即可 ,javatest 爲數據庫名 --> 

    </parameter> 

  </ResourceParams> 

  </Context>

 

 

 

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> 

 

java 中使用的代碼

 

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(); 

  }