Tomcat JDBC池：连接数过多

Question

Tomcat JDBC池：连接数过多

4

我正在使用Tomcat JDBC池来连接MySQL数据库连接池。JDBC池在应用程序的context.xml中声明为资源（而非全局级别）。我正在Eclipse IDE中开发此Web应用程序。因此，每当我对代码进行更改时，Eclipse会使Tomcat服务器重新加载context。

但问题在于，当context重新加载时，Tomcat会创建具有新连接但不释放旧池的JDBC池。在对代码进行更多更改后，Tomcat最终耗尽了MySQL服务器的最大连接限制，并开始显示“连接过多”错误。

我的context.xml文件如下：

<?xml version="1.0" encoding="UTF-8"?>
<Context>
    <Resource
        name="jdbc/myDB"
        auth="Container"
        type="javax.sql.DataSource"
        factory="org.apache.tomcat.jdbc.pool.DataSourceFactory"
        username="root"
        password="admin"
        driverClassName="com.mysql.jdbc.Driver"
        url="jdbc:mysql://localhost:3306/myDB?allowMultiQueries=true"
        defaultAutoCommit="false"
        initialSize="20"
        maxActive="50"
        maxIdle="30"
        minIdle="15"
        maxWait="5000"
        testOnBorrow="true"
        testWhileIdle="true"
        validationQuery="SELECT 1"
        timeBetweenEvictionRunsMillis="35000"
        minEvictableIdleTimeMillis="55000"
        removeAbandoned="true"
        removeAbandonedTimeout="3600"
        logAbandoned="true"
        validationInterval="35000"
    />
</Context>

我的web.xml文件如下:

<?xml version="1.0" encoding="UTF-8"?>
<web-app xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance" xmlns="http://xmlns.jcp.org/xml/ns/javaee" xsi:schemaLocation="http://xmlns.jcp.org/xml/ns/javaee http://xmlns.jcp.org/xml/ns/javaee/web-app_3_1.xsd" id="WebApp_ID" version="3.1">
  <display-name>MyApp</display-name>

  <welcome-file-list>
    <welcome-file>index.html</welcome-file>
    <welcome-file>index.jsp</welcome-file>
  </welcome-file-list>

  <resource-ref>
      <description>MyApp DB Connection</description>
      <res-ref-name>jdbc/myDB</res-ref-name>
      <res-type>javax.sql.DataSource</res-type>
      <res-auth>Container</res-auth>
  </resource-ref>

  <context-param>
    <param-name>data-source-lookup-name</param-name>
    <param-value>java:comp/env/jdbc/myDB</param-value>
  </context-param>

  <listener>
    <listener-class>com.project.listeners.AppListener</listener-class>
  </listener>
</web-app>

App Listener类似于：

package com.project.listeners;

import java.sql.Driver;
import java.sql.DriverManager;
import java.util.Enumeration;

import javax.servlet.ServletContext;
import javax.servlet.ServletContextEvent;
import javax.servlet.ServletContextListener;

import org.apache.log4j.Logger;

import com.mysql.jdbc.AbandonedConnectionCleanupThread;

public class AppListener implements ServletContextListener {
    private static Logger logger = Logger.getLogger(AppListener.class);

    @Override
    public void contextInitialized(ServletContextEvent event) {
        logger.info("Application context initialing");

        ServletContext context = event.getServletContext();

        DBObjectNames.dataSourceLookupName = context.getInitParameter("data-source-lookup-name");
        if(DBObjectNames.dataSourceLookupName == null){
            logger.fatal("data-source-lookup-name init parameter not supplied, using default: java:comp/env/jdbc/myDB");
            DBObjectNames.dataSourceLookupName = "java:comp/env/jdbc/myDB";
        }
        DBObjectNames.dataSourceLookupName = DBObjectNames.dataSourceLookupName.trim();
        logger.info("data-source-lookup-name set to: " + DBObjectNames.dataSourceLookupName);

        logger.info("Application context initialed");
    }

    @Override
    public void contextDestroyed(ServletContextEvent event) {
        logger.info("Application context destroying");

        try {
            logger.info("Shutting down AbandonedConnectionCleanupThread");
            AbandonedConnectionCleanupThread.shutdown();
            logger.info("Shut down AbandonedConnectionCleanupThread");
        } catch (Throwable t) {
            logger.fatal("Error while shutting down AbandonedConnectionCleanupThread", t);
        }

        Enumeration<Driver> drivers = DriverManager.getDrivers();
        while (drivers.hasMoreElements()) {
            Driver driver = drivers.nextElement();
            try {
                logger.info("Deregistering driver: " + driver);
                DriverManager.deregisterDriver(driver);
                logger.info("Deregistered driver: " + driver);
            } catch (Throwable t) {
                logger.fatal("Error while deregistering driver: " + driver, t);
            }
        }

        logger.info("Application context destroyed");
    }
}

我经常会遇到类似以下的异常：

Oct 30, 2014 4:16:54 PM org.apache.catalina.core.StandardContext reload
INFO: Reloading Context with name [/myapp] is completed
Oct 30, 2014 4:17:04 PM org.apache.catalina.core.StandardContext reload
INFO: Reloading Context with name [/myapp] has started
2014-10-30 16:17:04,497 [ContainerBackgroundProcessor[StandardEngine[Catalina]]] INFO  com.project.listeners.AppListener  - Application context destroying
2014-10-30 16:17:04,498 [ContainerBackgroundProcessor[StandardEngine[Catalina]]] INFO  com.project.listeners.AppListener  - Shutting down AbandonedConnectionCleanupThread
2014-10-30 16:17:04,498 [ContainerBackgroundProcessor[StandardEngine[Catalina]]] INFO  com.project.listeners.AppListener  - Shut down AbandonedConnectionCleanupThread
2014-10-30 16:17:04,498 [ContainerBackgroundProcessor[StandardEngine[Catalina]]] INFO  com.project.listeners.AppListener  - Application context destroyed
Oct 30, 2014 4:17:04 PM org.apache.jasper.servlet.TldScanner scanJars
INFO: At least one JAR was scanned for TLDs yet contained no TLDs. Enable debug logging for this logger for a complete list of JARs that were scanned but no TLDs were found in them. Skipping unneeded JARs during scanning can improve startup time and JSP compilation time.
2014-10-30 16:17:04,660 [ContainerBackgroundProcessor[StandardEngine[Catalina]]] INFO  com.project.listeners.AppListener  - Application context initialing
2014-10-30 16:17:04,661 [ContainerBackgroundProcessor[StandardEngine[Catalina]]] INFO  com.project.listeners.AppListener  - data-source-lookup-name set to: java:comp/env/jdbc/myDB
2014-10-30 16:17:04,662 [ContainerBackgroundProcessor[StandardEngine[Catalina]]] INFO  com.project.listeners.AppListener  - Application context initialed
Oct 30, 2014 4:17:04 PM org.apache.catalina.core.StandardContext reload
INFO: Reloading Context with name [/myapp] is completed
Oct 30, 2014 4:17:14 PM org.apache.catalina.core.StandardContext reload
INFO: Reloading Context with name [/myapp] has started
2014-10-30 16:17:14,665 [ContainerBackgroundProcessor[StandardEngine[Catalina]]] INFO  com.project.listeners.AppListener  - Application context destroying
2014-10-30 16:17:14,666 [ContainerBackgroundProcessor[StandardEngine[Catalina]]] INFO  com.project.listeners.AppListener  - Shutting down AbandonedConnectionCleanupThread
2014-10-30 16:17:14,666 [ContainerBackgroundProcessor[StandardEngine[Catalina]]] INFO  com.project.listeners.AppListener  - Shut down AbandonedConnectionCleanupThread
2014-10-30 16:17:14,666 [ContainerBackgroundProcessor[StandardEngine[Catalina]]] INFO  com.project.listeners.AppListener  - Application context destroyed
Oct 30, 2014 4:17:14 PM org.apache.tomcat.jdbc.pool.ConnectionPool init
SEVERE: Unable to create initial connections of pool.
com.mysql.jdbc.exceptions.jdbc4.MySQLNonTransientConnectionException: Data source rejected establishment of connection,  message from server: "Too many connections"
    at sun.reflect.NativeConstructorAccessorImpl.newInstance0(Native Method)
    at sun.reflect.NativeConstructorAccessorImpl.newInstance(Unknown Source)
    at sun.reflect.DelegatingConstructorAccessorImpl.newInstance(Unknown Source)
    at java.lang.reflect.Constructor.newInstance(Unknown Source)
    at com.mysql.jdbc.Util.handleNewInstance(Util.java:377)
    at com.mysql.jdbc.Util.getInstance(Util.java:360)
    at com.mysql.jdbc.SQLError.createSQLException(SQLError.java:956)
    at com.mysql.jdbc.SQLError.createSQLException(SQLError.java:935)
    at com.mysql.jdbc.SQLError.createSQLException(SQLError.java:924)
    at com.mysql.jdbc.MysqlIO.doHandshake(MysqlIO.java:1037)
    at com.mysql.jdbc.ConnectionImpl.coreConnect(ConnectionImpl.java:2234)
    at com.mysql.jdbc.ConnectionImpl.connectOneTryOnly(ConnectionImpl.java:2265)
    at com.mysql.jdbc.ConnectionImpl.createNewIO(ConnectionImpl.java:2064)
    at com.mysql.jdbc.ConnectionImpl.<init>(ConnectionImpl.java:790)
    at com.mysql.jdbc.JDBC4Connection.<init>(JDBC4Connection.java:44)
    at sun.reflect.GeneratedConstructorAccessor12.newInstance(Unknown Source)
    at sun.reflect.DelegatingConstructorAccessorImpl.newInstance(Unknown Source)
    at java.lang.reflect.Constructor.newInstance(Unknown Source)
    at com.mysql.jdbc.Util.handleNewInstance(Util.java:377)
    at com.mysql.jdbc.ConnectionImpl.getInstance(ConnectionImpl.java:395)
    at com.mysql.jdbc.NonRegisteringDriver.connect(NonRegisteringDriver.java:325)
    at org.apache.tomcat.jdbc.pool.PooledConnection.connectUsingDriver(PooledConnection.java:307)
    at org.apache.tomcat.jdbc.pool.PooledConnection.connect(PooledConnection.java:200)
    at org.apache.tomcat.jdbc.pool.ConnectionPool.createConnection(ConnectionPool.java:699)
    at org.apache.tomcat.jdbc.pool.ConnectionPool.borrowConnection(ConnectionPool.java:633)
    at org.apache.tomcat.jdbc.pool.ConnectionPool.init(ConnectionPool.java:484)
    at org.apache.tomcat.jdbc.pool.ConnectionPool.<init>(ConnectionPool.java:142)
    at org.apache.tomcat.jdbc.pool.DataSourceProxy.pCreatePool(DataSourceProxy.java:115)
    at org.apache.tomcat.jdbc.pool.DataSourceProxy.createPool(DataSourceProxy.java:102)
    at org.apache.tomcat.jdbc.pool.DataSourceFactory.createDataSource(DataSourceFactory.java:553)
    at org.apache.tomcat.jdbc.pool.DataSourceFactory.getObjectInstance(DataSourceFactory.java:241)
    at org.apache.naming.factory.FactoryBase.getObjectInstance(FactoryBase.java:94)
    at javax.naming.spi.NamingManager.getObjectInstance(Unknown Source)
    at org.apache.naming.NamingContext.lookup(NamingContext.java:841)
    at org.apache.naming.NamingContext.lookup(NamingContext.java:152)
    at org.apache.naming.NamingContext.lookup(NamingContext.java:829)
    at org.apache.naming.NamingContext.lookup(NamingContext.java:166)
    at org.apache.catalina.core.NamingContextListener.addResource(NamingContextListener.java:1084)
    at org.apache.catalina.core.NamingContextListener.createNamingContext(NamingContextListener.java:663)
    at org.apache.catalina.core.NamingContextListener.lifecycleEvent(NamingContextListener.java:256)
    at org.apache.catalina.util.LifecycleSupport.fireLifecycleEvent(LifecycleSupport.java:117)
    at org.apache.catalina.util.LifecycleBase.fireLifecycleEvent(LifecycleBase.java:90)
    at org.apache.catalina.core.StandardContext.startInternal(StandardContext.java:5120)
    at org.apache.catalina.util.LifecycleBase.start(LifecycleBase.java:150)
    at org.apache.catalina.core.StandardContext.reload(StandardContext.java:3821)
    at org.apache.catalina.loader.WebappLoader.backgroundProcess(WebappLoader.java:292)
    at org.apache.catalina.core.StandardContext.backgroundProcess(StandardContext.java:5576)
    at org.apache.catalina.core.ContainerBase$ContainerBackgroundProcessor.processChildren(ContainerBase.java:1377)
    at org.apache.catalina.core.ContainerBase$ContainerBackgroundProcessor.processChildren(ContainerBase.java:1381)
    at org.apache.catalina.core.ContainerBase$ContainerBackgroundProcessor.processChildren(ContainerBase.java:1381)
    at org.apache.catalina.core.ContainerBase$ContainerBackgroundProcessor.run(ContainerBase.java:1349)
    at java.lang.Thread.run(Unknown Source)

Oct 30, 2014 4:17:14 PM org.apache.tomcat.jdbc.pool.ConnectionPool abandon
WARNING: Connection has been abandoned PooledConnection[com.mysql.jdbc.JDBC4Connection@1090e8d6]:java.lang.Exception
    at org.apache.tomcat.jdbc.pool.ConnectionPool.getThreadDump(ConnectionPool.java:1052)
    at org.apache.tomcat.jdbc.pool.ConnectionPool.createConnection(ConnectionPool.java:704)
    at org.apache.tomcat.jdbc.pool.ConnectionPool.borrowConnection(ConnectionPool.java:633)
    at org.apache.tomcat.jdbc.pool.ConnectionPool.init(ConnectionPool.java:484)
    at org.apache.tomcat.jdbc.pool.ConnectionPool.<init>(ConnectionPool.java:142)
    at org.apache.tomcat.jdbc.pool.DataSourceProxy.pCreatePool(DataSourceProxy.java:115)
    at org.apache.tomcat.jdbc.pool.DataSourceProxy.createPool(DataSourceProxy.java:102)
    at org.apache.tomcat.jdbc.pool.DataSourceFactory.createDataSource(DataSourceFactory.java:553)
    at org.apache.tomcat.jdbc.pool.DataSourceFactory.getObjectInstance(DataSourceFactory.java:241)
    at org.apache.naming.factory.FactoryBase.getObjectInstance(FactoryBase.java:94)
    at javax.naming.spi.NamingManager.getObjectInstance(Unknown Source)
    at org.apache.naming.NamingContext.lookup(NamingContext.java:841)
    at org.apache.naming.NamingContext.lookup(NamingContext.java:152)
    at org.apache.naming.NamingContext.lookup(NamingContext.java:829)
    at org.apache.naming.NamingContext.lookup(NamingContext.java:166)
    at org.apache.catalina.core.NamingContextListener.addResource(NamingContextListener.java:1084)
    at org.apache.catalina.core.NamingContextListener.createNamingContext(NamingContextListener.java:663)
    at org.apache.catalina.core.NamingContextListener.lifecycleEvent(NamingContextListener.java:256)
    at org.apache.catalina.util.LifecycleSupport.fireLifecycleEvent(LifecycleSupport.java:117)
    at org.apache.catalina.util.LifecycleBase.fireLifecycleEvent(LifecycleBase.java:90)
    at org.apache.catalina.core.StandardContext.startInternal(StandardContext.java:5120)
    at org.apache.catalina.util.LifecycleBase.start(LifecycleBase.java:150)
    at org.apache.catalina.core.StandardContext.reload(StandardContext.java:3821)
    at org.apache.catalina.loader.WebappLoader.backgroundProcess(WebappLoader.java:292)
    at org.apache.catalina.core.StandardContext.backgroundProcess(StandardContext.java:5576)
    at org.apache.catalina.core.ContainerBase$ContainerBackgroundProcessor.processChildren(ContainerBase.java:1377)
    at org.apache.catalina.core.ContainerBase$ContainerBackgroundProcessor.processChildren(ContainerBase.java:1381)
    at org.apache.catalina.core.ContainerBase$ContainerBackgroundProcessor.processChildren(ContainerBase.java:1381)
    at org.apache.catalina.core.ContainerBase$ContainerBackgroundProcessor.run(ContainerBase.java:1349)
    at java.lang.Thread.run(Unknown Source)

Oct 30, 2014 4:17:14 PM org.apache.tomcat.jdbc.pool.ConnectionPool abandon
WARNING: Connection has been abandoned PooledConnection[com.mysql.jdbc.JDBC4Connection@c572aa4]:java.lang.Exception
    at org.apache.tomcat.jdbc.pool.ConnectionPool.getThreadDump(ConnectionPool.java:1052)
    at org.apache.tomcat.jdbc.pool.ConnectionPool.createConnection(ConnectionPool.java:704)
    at org.apache.tomcat.jdbc.pool.ConnectionPool.borrowConnection(ConnectionPool.java:633)
    at org.apache.tomcat.jdbc.pool.ConnectionPool.init(ConnectionPool.java:484)
    at org.apache.tomcat.jdbc.pool.ConnectionPool.<init>(ConnectionPool.java:142)
    at org.apache.tomcat.jdbc.pool.DataSourceProxy.pCreatePool(DataSourceProxy.java:115)
    at org.apache.tomcat.jdbc.pool.DataSourceProxy.createPool(DataSourceProxy.java:102)
    at org.apache.tomcat.jdbc.pool.DataSourceFactory.createDataSource(DataSourceFactory.java:553)
    at org.apache.tomcat.jdbc.pool.DataSourceFactory.getObjectInstance(DataSourceFactory.java:241)
    at org.apache.naming.factory.FactoryBase.getObjectInstance(FactoryBase.java:94)
    at javax.naming.spi.NamingManager.getObjectInstance(Unknown Source)
    at org.apache.naming.NamingContext.lookup(NamingContext.java:841)
    at org.apache.naming.NamingContext.lookup(NamingContext.java:152)
    at org.apache.naming.NamingContext.lookup(NamingContext.java:829)
    at org.apache.naming.NamingContext.lookup(NamingContext.java:166)
    at org.apache.catalina.core.NamingContextListener.addResource(NamingContextListener.java:1084)
    at org.apache.catalina.core.NamingContextListener.createNamingContext(NamingContextListener.java:663)
    at org.apache.catalina.core.NamingContextListener.lifecycleEvent(NamingContextListener.java:256)
    at org.apache.catalina.util.LifecycleSupport.fireLifecycleEvent(LifecycleSupport.java:117)
    at org.apache.catalina.util.LifecycleBase.fireLifecycleEvent(LifecycleBase.java:90)
    at org.apache.catalina.core.StandardContext.startInternal(StandardContext.java:5120)
    at org.apache.catalina.util.LifecycleBase.start(LifecycleBase.java:150)
    at org.apache.catalina.core.StandardContext.reload(StandardContext.java:3821)
    at org.apache.catalina.loader.WebappLoader.backgroundProcess(WebappLoader.java:292)
    at org.apache.catalina.core.StandardContext.backgroundProcess(StandardContext.java:5576)
    at org.apache.catalina.core.ContainerBase$ContainerBackgroundProcessor.processChildren(ContainerBase.java:1377)
    at org.apache.catalina.core.ContainerBase$ContainerBackgroundProcessor.processChildren(ContainerBase.java:1381)
    at org.apache.catalina.core.ContainerBase$ContainerBackgroundProcessor.processChildren(ContainerBase.java:1381)
    at org.apache.catalina.core.ContainerBase$ContainerBackgroundProcessor.run(ContainerBase.java:1349)
    at java.lang.Thread.run(Unknown Source)

Oct 30, 2014 4:17:14 PM org.apache.tomcat.jdbc.pool.ConnectionPool abandon
WARNING: Connection has been abandoned PooledConnection[com.mysql.jdbc.JDBC4Connection@72e8fcdd]:java.lang.Exception
    at org.apache.tomcat.jdbc.pool.ConnectionPool.getThreadDump(ConnectionPool.java:1052)
    at org.apache.tomcat.jdbc.pool.ConnectionPool.createConnection(ConnectionPool.java:704)
    at org.apache.tomcat.jdbc.pool.ConnectionPool.borrowConnection(ConnectionPool.java:633)
    at org.apache.tomcat.jdbc.pool.ConnectionPool.init(ConnectionPool.java:484)
    at org.apache.tomcat.jdbc.pool.ConnectionPool.<init>(ConnectionPool.java:142)
    at org.apache.tomcat.jdbc.pool.DataSourceProxy.pCreatePool(DataSourceProxy.java:115)
    at org.apache.tomcat.jdbc.pool.DataSourceProxy.createPool(DataSourceProxy.java:102)
    at org.apache.tomcat.jdbc.pool.DataSourceFactory.createDataSource(DataSourceFactory.java:553)
    at org.apache.tomcat.jdbc.pool.DataSourceFactory.getObjectInstance(DataSourceFactory.java:241)
    at org.apache.naming.factory.FactoryBase.getObjectInstance(FactoryBase.java:94)
    at javax.naming.spi.NamingManager.getObjectInstance(Unknown Source)
    at org.apache.naming.NamingContext.lookup(NamingContext.java:841)
    at org.apache.naming.NamingContext.lookup(NamingContext.java:152)
    at org.apache.naming.NamingContext.lookup(NamingContext.java:829)
    at org.apache.naming.NamingContext.lookup(NamingContext.java:166)
    at org.apache.catalina.core.NamingContextListener.addResource(NamingContextListener.java:1084)
    at org.apache.catalina.core.NamingContextListener.createNamingContext(NamingContextListener.java:663)
    at org.apache.catalina.core.NamingContextListener.lifecycleEvent(NamingContextListener.java:256)
    at org.apache.catalina.util.LifecycleSupport.fireLifecycleEvent(LifecycleSupport.java:117)
    at org.apache.catalina.util.LifecycleBase.fireLifecycleEvent(LifecycleBase.java:90)
    at org.apache.catalina.core.StandardContext.startInternal(StandardContext.java:5120)
    at org.apache.catalina.util.LifecycleBase.start(LifecycleBase.java:150)
    at org.apache.catalina.core.StandardContext.reload(StandardContext.java:3821)
    at org.apache.catalina.loader.WebappLoader.backgroundProcess(WebappLoader.java:292)
    at org.apache.catalina.core.StandardContext.backgroundProcess(StandardContext.java:5576)
    at org.apache.catalina.core.ContainerBase$ContainerBackgroundProcessor.processChildren(ContainerBase.java:1377)
    at org.apache.catalina.core.ContainerBase$ContainerBackgroundProcessor.processChildren(ContainerBase.java:1381)
    at org.apache.catalina.core.ContainerBase$ContainerBackgroundProcessor.processChildren(ContainerBase.java:1381)
    at org.apache.catalina.core.ContainerBase$ContainerBackgroundProcessor.run(ContainerBase.java:1349)
    at java.lang.Thread.run(Unknown Source)

Oct 30, 2014 4:17:14 PM org.apache.naming.NamingContext lookup
WARNING: Unexpected exception resolving reference
com.mysql.jdbc.exceptions.jdbc4.MySQLNonTransientConnectionException: Data source rejected establishment of connection,  message from server: "Too many connections"
    at sun.reflect.NativeConstructorAccessorImpl.newInstance0(Native Method)
    at sun.reflect.NativeConstructorAccessorImpl.newInstance(Unknown Source)
    at sun.reflect.DelegatingConstructorAccessorImpl.newInstance(Unknown Source)
    at java.lang.reflect.Constructor.newInstance(Unknown Source)
    at com.mysql.jdbc.Util.handleNewInstance(Util.java:377)
    at com.mysql.jdbc.Util.getInstance(Util.java:360)
    at com.mysql.jdbc.SQLError.createSQLException(SQLError.java:956)
    at com.mysql.jdbc.SQLError.createSQLException(SQLError.java:935)
    at com.mysql.jdbc.SQLError.createSQLException(SQLError.java:924)
    at com.mysql.jdbc.MysqlIO.doHandshake(MysqlIO.java:1037)
    at com.mysql.jdbc.ConnectionImpl.coreConnect(ConnectionImpl.java:2234)
    at com.mysql.jdbc.ConnectionImpl.connectOneTryOnly(ConnectionImpl.java:2265)
    at com.mysql.jdbc.ConnectionImpl.createNewIO(ConnectionImpl.java:2064)
    at com.mysql.jdbc.ConnectionImpl.<init>(ConnectionImpl.java:790)
    at com.mysql.jdbc.JDBC4Connection.<init>(JDBC4Connection.java:44)
    at sun.reflect.GeneratedConstructorAccessor12.newInstance(Unknown Source)
    at sun.reflect.DelegatingConstructorAccessorImpl.newInstance(Unknown Source)
    at java.lang.reflect.Constructor.newInstance(Unknown Source)
    at com.mysql.jdbc.Util.handleNewInstance(Util.java:377)
    at com.mysql.jdbc.ConnectionImpl.getInstance(ConnectionImpl.java:395)
    at com.mysql.jdbc.NonRegisteringDriver.connect(NonRegisteringDriver.java:325)
    at org.apache.tomcat.jdbc.pool.PooledConnection.connectUsingDriver(PooledConnection.java:307)
    at org.apache.tomcat.jdbc.pool.PooledConnection.connect(PooledConnection.java:200)
    at org.apache.tomcat.jdbc.pool.ConnectionPool.createConnection(ConnectionPool.java:699)
    at org.apache.tomcat.jdbc.pool.ConnectionPool.borrowConnection(ConnectionPool.java:633)
    at org.apache.tomcat.jdbc.pool.ConnectionPool.init(ConnectionPool.java:484)
    at org.apache.tomcat.jdbc.pool.ConnectionPool.<init>(ConnectionPool.java:142)
    at org.apache.tomcat.jdbc.pool.DataSourceProxy.pCreatePool(DataSourceProxy.java:115)
    at org.apache.tomcat.jdbc.pool.DataSourceProxy.createPool(DataSourceProxy.java:102)
    at org.apache.tomcat.jdbc.pool.DataSourceFactory.createDataSource(DataSourceFactory.java:553)
    at org.apache.tomcat.jdbc.pool.DataSourceFactory.getObjectInstance(DataSourceFactory.java:241)
    at org.apache.naming.factory.FactoryBase.getObjectInstance(FactoryBase.java:94)
    at javax.naming.spi.NamingManager.getObjectInstance(Unknown Source)
    at org.apache.naming.NamingContext.lookup(NamingContext.java:841)
    at org.apache.naming.NamingContext.lookup(NamingContext.java:152)
    at org.apache.naming.NamingContext.lookup(NamingContext.java:829)
    at org.apache.naming.NamingContext.lookup(NamingContext.java:166)
    at org.apache.catalina.core.NamingContextListener.addResource(NamingContextListener.java:1084)
    at org.apache.catalina.core.NamingContextListener.createNamingContext(NamingContextListener.java:663)
    at org.apache.catalina.core.NamingContextListener.lifecycleEvent(NamingContextListener.java:256)
    at org.apache.catalina.util.LifecycleSupport.fireLifecycleEvent(LifecycleSupport.java:117)
    at org.apache.catalina.util.LifecycleBase.fireLifecycleEvent(LifecycleBase.java:90)
    at org.apache.catalina.core.StandardContext.startInternal(StandardContext.java:5120)
    at org.apache.catalina.util.LifecycleBase.start(LifecycleBase.java:150)
    at org.apache.catalina.core.StandardContext.reload(StandardContext.java:3821)
    at org.apache.catalina.loader.WebappLoader.backgroundProcess(WebappLoader.java:292)
    at org.apache.catalina.core.StandardContext.backgroundProcess(StandardContext.java:5576)
    at org.apache.catalina.core.ContainerBase$ContainerBackgroundProcessor.processChildren(ContainerBase.java:1377)
    at org.apache.catalina.core.ContainerBase$ContainerBackgroundProcessor.processChildren(ContainerBase.java:1381)
    at org.apache.catalina.core.ContainerBase$ContainerBackgroundProcessor.processChildren(ContainerBase.java:1381)
    at org.apache.catalina.core.ContainerBase$ContainerBackgroundProcessor.run(ContainerBase.java:1349)
    at java.lang.Thread.run(Unknown Source)

Oct 30, 2014 4:17:14 PM org.apache.catalina.core.NamingContextListener addResource
WARNING: Failed to register in JMX: javax.naming.NamingException: Data source rejected establishment of connection,  message from server: "Too many connections"
Oct 30, 2014 4:17:14 PM org.apache.jasper.servlet.TldScanner scanJars
INFO: At least one JAR was scanned for TLDs yet contained no TLDs. Enable debug logging for this logger for a complete list of JARs that were scanned but no TLDs were found in them. Skipping unneeded JARs during scanning can improve startup time and JSP compilation time.
2014-10-30 16:17:14,788 [ContainerBackgroundProcessor[StandardEngine[Catalina]]] INFO  com.project.listeners.AppListener  - Application context initialing
2014-10-30 16:17:14,789 [ContainerBackgroundProcessor[StandardEngine[Catalina]]] INFO  com.project.listeners.AppListener  - data-source-lookup-name set to: java:comp/env/jdbc/myDB
2014-10-30 16:17:14,791 [ContainerBackgroundProcessor[StandardEngine[Catalina]]] INFO  com.project.listeners.AppListener  - Application context initialed
Oct 30, 2014 4:17:14 PM org.apache.catalina.core.StandardContext reload
INFO: Reloading Context with name [/myapp] is completed

更多信息：

这些内容没有经过应用测试，即我没有执行Web应用程序来打开连接，仅仅是编写代码，因此不会有任何打开连接并保持连接而不关闭它的问题。

使用Apache Tomcat：版本8.0和Eclipse Luna Release。

请在这方面帮助我。

编辑

每次上下文重新加载时，在MySQL Workbench中看到更多的15个已打开的连接到DB，然后命中最大连接限制151个连接到MySQL服务器。

- nullptr

4个回答

5

移除 factory="org.apache.tomcat.jdbc.pool.DataSourceFactory"

最近升级到apache-tomcat-8.0.28后，DataSource配置中添加了"factory=..."，然后与oracle数据库的连接会话变得异常。将其删除后，连接会话恢复正常状态。我尝试理解原因，但是没有成功。这条评论可能对其他人有所帮助。

以下是来自Apache TomEE http://tomee.apache.org/datasource-config.html的数据源配置。它应该是任何寻找解决方案的人的好参考。

<Resource id="myDataSource" type="javax.sql.DataSource">
    accessToUnderlyingConnectionAllowed = false
    alternateUsernameAllowed = false
    connectionProperties = 
    defaultAutoCommit = true
    defaultReadOnly = 
    definition = 
    ignoreDefaultValues = false
    initialSize = 0
    jdbcDriver = org.hsqldb.jdbcDriver
    jdbcUrl = jdbc:hsqldb:mem:hsqldb
    jtaManaged = true
    maxActive = 20
    maxIdle = 20
    maxOpenPreparedStatements = 0
    maxWaitTime = -1 millisecond
    minEvictableIdleTime = 30 minutes
    minIdle = 0
    numTestsPerEvictionRun = 3
    password = 
    passwordCipher = PlainText
    poolPreparedStatements = false
    serviceId = 
    testOnBorrow = true
    testOnReturn = false
    testWhileIdle = false
    timeBetweenEvictionRuns = -1 millisecond
    userName = sa
    validationQuery = 
</Resource>

- caot

1

即使假设这是正确的，没有解释也没有用。 - David Hoelzer

@David，你证明它是错误的了吗？它对我的apache-tomcat-8.0.28有效。 - caot

我并没有说这是错误的。我说如果没有解释，它是没有帮助的。我猜这就是为什么这被踩而我的评论被赞的原因。 - David Hoelzer

@David 你可能在寻找解决方案，但我可能错了，因为你可能只是为了点赞而发表评论。 - caot

1

不，@caot。我发表评论是为了帮助你改进你的答案。作为SE/SO社区的一员，社区编辑是其中重要的一部分。实际上，我对这个问题完全没有兴趣，但我投入了精力来确保其他寻找答案的人能够找到他们可以理解的高质量答案。希望这能有所帮助，欢迎来到StackOverflow！ - David Hoelzer

1

谢谢，@David。已添加更多解释。 - caot

1

如果我们使用一个Hibernate属性文件进行配置，我认为这将足够：

hibernate.transaction.auto_close_session

- Impresi MLine

1

更详细的解释会更好。 :-) - Andreas

0

我有类似的问题，但我的环境略有不同。

我有一个springboot应用程序和mariadb 10.34。

我在application-*.properties中定义了所有属性。

我已经注释掉了所有以spring.datasource.tomcat开头的配置（您也可以删除它们），现在它正在工作。

我猜，我的团队中有人没有进行代码审查就提交了代码。:):)

参考：https://github.com/HomoEfficio/dev-tips/blob/master/%EA%B0%84%ED%97%90%EC%A0%81%EC%9D%B8%20Too%20many%20connections%20%EC%97%90%EB%9F%AC.md

（如果您不懂韩语，那么您可以使用https://translate.google.com/ :D :D）

- Manan Shah

网页内容由stack overflow 提供, 点击上面的

可以查看英文原文，
原文链接

- jakub.petr · Accepted Answer

我认为你需要在context.xml中的Resource标签里添加closeMethod="close"。这样当你重新加载context时，Tomcat会关闭你的DB连接。

修改后的context.xml:

<?xml version="1.0" encoding="UTF-8"?>
 <Context>
    <Resource
        name="jdbc/myDB"
        auth="Container"
        type="javax.sql.DataSource"
        factory="org.apache.tomcat.jdbc.pool.DataSourceFactory"
        username="root"
        password="admin"
        driverClassName="com.mysql.jdbc.Driver"
        url="jdbc:mysql://localhost:3306/myDB?allowMultiQueries=true"
        defaultAutoCommit="false"
        initialSize="20"
        maxActive="50"
        maxIdle="30"
        minIdle="15"
        maxWait="5000"
        testOnBorrow="true"
        testWhileIdle="true"
        validationQuery="SELECT 1"
        timeBetweenEvictionRunsMillis="35000"
        minEvictableIdleTimeMillis="55000"
        removeAbandoned="true"
        removeAbandonedTimeout="3600"
        logAbandoned="true"
        validationInterval="35000"
        closeMethod="close"
    />
</Context>