无法获得 JDBC 连接；嵌套异常是java.sql.SQLException：在java中预加载连接池时出错[重复]

Question

您好，我正在使用带有 jdbc 模板的 spring 连接到带有 dbcp2 数据源的数据库。

<bean id="dataSourcecool" class="org.apache.commons.dbcp2.BasicDataSource" destroy-method="close">
        <property name="driverClassName" value="com.mysql.jdbc.Driver" />
        <property name="url" value="RDS URL?zeroDateTimeBehavior=convertToNull" />
        <property name="username" value="xxxxx" />
        <property name="password" value="YYYYYYY" />
        <property name="defaultAutoCommit" value="true"/>
        <property name="initialSize" value="150"/>
        <property name="maxTotal" value="100"/>
        <property name="maxIdle" value="0"/>
        <property name="minIdle" value="0"/>
        <property name="maxWaitMillis" value="10000"/>
        <property name="validationQuery" value="SELECT NOW();"/>
        <property name="timeBetweenEvictionRunsMillis" value="10000"/>      
        <property name="removeAbandonedOnMaintenance" value="true"/>
        <property name="maxConnLifetimeMillis" value="10000"/>
        <property name="minEvictableIdleTimeMillis" value="1000"/>
    </bean>

具有 3 个数据库的相同配置和所有数据库都存在于 5 个服务器中。 我的 RDS 的最大连接数为 800，发现我的异常如下 我的方法中的异常::org.springframework.jdbc.CannotGetJdbcConnectionException: 无法获取 JDBC 连接；嵌套异常是 java.sql.SQLException: Error preloading the connection pool

谁能告诉我是什么导致了这个错误，让我知道我需要在这里采用哪些数据库配置。提前致谢。

完整的堆栈跟踪在这里

org.springframework.jdbc.CannotGetJdbcConnectionException: Could not get JDBC Connection; nested exception is java.sql.SQLException: Error preloading the connection pool
 at org.springframework.jdbc.datasource.DataSourceUtils.getConnection(DataSourceUtils.java:80)
 at org.springframework.jdbc.core.JdbcTemplate.execute(JdbcTemplate.java:619)
 at org.springframework.jdbc.core.JdbcTemplate.query(JdbcTemplate.java:684)
 at org.springframework.jdbc.core.JdbcTemplate.query(JdbcTemplate.java:716)
 at org.springframework.jdbc.core.JdbcTemplate.query(JdbcTemplate.java:726)
 at org.springframework.jdbc.core.JdbcTemplate.queryForRowSet(JdbcTemplate.java:863)
 MY CLASS
 at 
 My class
 at sun.reflect.NativeMethodAccessorImpl.invoke0(Native Method)
 at sun.reflect.NativeMethodAccessorImpl.invoke(NativeMethodAccessorImpl.java:57)
 at sun.reflect.DelegatingMethodAccessorImpl.invoke(DelegatingMethodAccessorImpl.java:43)
 at java.lang.reflect.Method.invoke(Method.java:606)
 at org.springframework.web.method.support.InvocableHandlerMethod.doInvoke(InvocableHandlerMethod.java:220)
 at org.springframework.web.method.support.InvocableHandlerMethod.invokeForRequest(InvocableHandlerMethod.java:134)
 at org.springframework.web.servlet.mvc.method.annotation.ServletInvocableHandlerMethod.invokeAndHandle(ServletInvocableHandlerMethod.java:116)
 at org.springframework.web.servlet.mvc.method.annotation.RequestMappingHandlerAdapter.invokeHandlerMethod(RequestMappingHandlerAdapter.java:827)
 at org.springframework.web.servlet.mvc.method.annotation.RequestMappingHandlerAdapter.handleInternal(RequestMappingHandlerAdapter.java:738)
 at org.springframework.web.servlet.mvc.method.AbstractHandlerMethodAdapter.handle(AbstractHandlerMethodAdapter.java:85)
 at org.springframework.web.servlet.DispatcherServlet.doDispatch(DispatcherServlet.java:963)
 at org.springframework.web.servlet.DispatcherServlet.doService(DispatcherServlet.java:897)
 at org.springframework.web.servlet.FrameworkServlet.processRequest(FrameworkServlet.java:970)
 at org.springframework.web.servlet.FrameworkServlet.doPut(FrameworkServlet.java:883)
 at javax.servlet.http.HttpServlet.service(HttpServlet.java:653)
 at org.springframework.web.servlet.FrameworkServlet.service(FrameworkServlet.java:846)
 at javax.servlet.http.HttpServlet.service(HttpServlet.java:731)
 at org.apache.catalina.core.ApplicationFilterChain.internalDoFilter(ApplicationFilterChain.java:303)
 at org.apache.catalina.core.ApplicationFilterChain.doFilter(ApplicationFilterChain.java:208)
 at org.apache.tomcat.websocket.server.WsFilter.doFilter(WsFilter.java:52)
 at org.apache.catalina.core.ApplicationFilterChain.internalDoFilter(ApplicationFilterChain.java:241)
 at org.apache.catalina.core.ApplicationFilterChain.doFilter(ApplicationFilterChain.java:208)
 at org.apache.catalina.core.StandardWrapperValve.invoke(StandardWrapperValve.java:218)
 at org.apache.catalina.core.StandardContextValve.invoke(StandardContextValve.java:122)
 at org.apache.catalina.authenticator.AuthenticatorBase.invoke(AuthenticatorBase.java:505)
 at org.apache.catalina.core.StandardHostValve.invoke(StandardHostValve.java:169)
 at org.apache.catalina.valves.ErrorReportValve.invoke(ErrorReportValve.java:103)
 at org.apache.catalina.valves.AccessLogValve.invoke(AccessLogValve.java:956)
 at org.apache.catalina.core.StandardEngineValve.invoke(StandardEngineValve.java:116)
 at org.apache.catalina.connector.CoyoteAdapter.service(CoyoteAdapter.java:442)
 at org.apache.coyote.ajp.AjpProcessor.process(AjpProcessor.java:190)
 at org.apache.coyote.AbstractProtocol$AbstractConnectionHandler.process(AbstractProtocol.java:640)
 at org.apache.tomcat.util.net.JIoEndpoint$SocketProcessor.run(JIoEndpoint.java:316)
 at java.util.concurrent.ThreadPoolExecutor.runWorker(ThreadPoolExecutor.java:1145)
 at java.util.concurrent.ThreadPoolExecutor$Worker.run(ThreadPoolExecutor.java:615)
 at org.apache.tomcat.util.threads.TaskThread$WrappingRunnable.run(TaskThread.java:61)
 at java.lang.Thread.run(Thread.java:745)
Caused by: java.sql.SQLException: Error preloading the connection pool
 at org.apache.commons.dbcp2.BasicDataSource.createDataSource(BasicDataSource.java:2085)
 at org.apache.commons.dbcp2.BasicDataSource.getConnection(BasicDataSource.java:1533)
 at org.springframework.jdbc.datasource.DataSourceUtils.doGetConnection(DataSourceUtils.java:111)
 at org.springframework.jdbc.datasource.DataSourceUtils.getConnection(DataSourceUtils.java:77)
 ... 45 more
Caused by: java.sql.SQLException: Data source rejected establishment of connection,  message from server: "Too many connections"
 at com.mysql.jdbc.MysqlIO.checkErrorPacket(MysqlIO.java:1905)
 at com.mysql.jdbc.MysqlIO.checkErrorPacket(MysqlIO.java:1831)
 at com.mysql.jdbc.MysqlIO.secureAuth411(MysqlIO.java:2389)
 at com.mysql.jdbc.MysqlIO.doHandshake(MysqlIO.java:757)
 at com.mysql.jdbc.Connection.createNewIO(Connection.java:1654)
 at com.mysql.jdbc.Connection.<init>(Connection.java:432)
 at com.mysql.jdbc.NonRegisteringDriver.connect(NonRegisteringDriver.java:400)
 at org.apache.commons.dbcp2.DriverConnectionFactory.createConnection(DriverConnectionFactory.java:39)
 at org.apache.commons.dbcp2.PoolableConnectionFactory.makeObject(PoolableConnectionFactory.java:256)
 at org.apache.commons.pool2.impl.GenericObjectPool.create(GenericObjectPool.java:868)
 at org.apache.commons.pool2.impl.GenericObjectPool.addObject(GenericObjectPool.java:961)
 at org.apache.commons.dbcp2.BasicDataSource.createDataSource(BasicDataSource.java:2081)
 ... 48 more
org.springframework.jdbc.CannotGetJdbcConnectionException: Could not get JDBC Connection; nested exception is java.sql.SQLException: Error preloading the connection pool
 at org.springframework.jdbc.datasource.DataSourceUtils.getConnection(DataSourceUtils.java:80)
 at org.springframework.jdbc.core.JdbcTemplate.execute(JdbcTemplate.java:619)
 at org.springframework.jdbc.core.JdbcTemplate.query(JdbcTemplate.java:684)
 at org.springframework.jdbc.core.JdbcTemplate.query(JdbcTemplate.java:716)
 at org.springframework.jdbc.core.JdbcTemplate.query(JdbcTemplate.java:726)
 at org.springframework.jdbc.core.JdbcTemplate.queryForRowSet(JdbcTemplate.java:863)
 My code
 
 at sun.reflect.NativeMethodAccessorImpl.invoke0(Native Method)
 at sun.reflect.NativeMethodAccessorImpl.invoke(NativeMethodAccessorImpl.java:57)
 at sun.reflect.DelegatingMethodAccessorImpl.invoke(DelegatingMethodAccessorImpl.java:43)
 at java.lang.reflect.Method.invoke(Method.java:606)
 at org.springframework.web.method.support.InvocableHandlerMethod.doInvoke(InvocableHandlerMethod.java:220)
 at org.springframework.web.method.support.InvocableHandlerMethod.invokeForRequest(InvocableHandlerMethod.java:134)
 at org.springframework.web.servlet.mvc.method.annotation.ServletInvocableHandlerMethod.invokeAndHandle(ServletInvocableHandlerMethod.java:116)
 at org.springframework.web.servlet.mvc.method.annotation.RequestMappingHandlerAdapter.invokeHandlerMethod(RequestMappingHandlerAdapter.java:827)
 at org.springframework.web.servlet.mvc.method.annotation.RequestMappingHandlerAdapter.handleInternal(RequestMappingHandlerAdapter.java:738)
 at org.springframework.web.servlet.mvc.method.AbstractHandlerMethodAdapter.handle(AbstractHandlerMethodAdapter.java:85)
 at org.springframework.web.servlet.DispatcherServlet.doDispatch(DispatcherServlet.java:963)
 at..

Answer 1

堆栈跟踪清楚地表明"Too many connections"。你应该减少你的initialSize 值，试试5 之类的东西，看看它是否能解决你的问题。注意maxTotal 应该大于initialSize。你应该注意maxIdle和minIdle的设置，其实DBCP documentation说：

注意：如果在重负载系统上将 maxIdle 设置得太低，则 可能你会看到连接被关闭并且几乎立即 正在打开的新连接。这是活动线程的结果 暂时关闭连接的速度比打开连接的速度快， 导致空闲连接数超过 maxIdle。最好的 重负载系统的 maxIdle 值会有所不同，但默认值 是一个很好的起点。

调整连接池的大小并非易事，您应该研究自己的情况。欲了解更多信息，您可以阅读About Pool Sizing、Professional connection pool sizing，并查看此related question。