org.springframework.jdbc.CannotGetJdbcConnectionException: Could not get JDBC Connection

来源：互联网发布：sql最后一行加合计行编辑：程序博客网时间：2024/05/17 07:28

 最近在复习ssm时，做了一个小demo。在这其中就遇到许多问题，而出现这些问题时，让自己最大的一个感受就是多翻阅官方文档。虽然现在市场有许多书籍和视频，这些资源用归用。但是当你跟着这些教程走下去，最会有一些问题的。自己也有从中查看出来。

例如:
org.mybatis.spring.MyBatisSystemException: nested exception is org.apache.ibatis.exceptions.PersistenceException:

Error querying database. Cause: org.springframework.jdbc.CannotGetJdbcConnectionException: Could not get JDBC Connection; nested exception is java.sql.SQLException: An attempt by a client to checkout a Connection has timed out.

The error may exist in file [C:\seckill\target\classes\mapper\SeckillDao.xml]

The error may involve org.seckill.dao.SeckillDao.queryById

The error occurred while executing a query

Cause: org.springframework.jdbc.CannotGetJdbcConnectionException: Could not get JDBC Connection; nested exception is java.sql.SQLException: An attempt by a client to checkout a Connection has timed out.

at org.mybatis.spring.MyBatisExceptionTranslator.translateExceptionIfPossible(MyBatisExceptionTranslator.java:76)at org.mybatis.spring.SqlSessionTemplate$SqlSessionInterceptor.invoke(SqlSessionTemplate.java:399)at com.sun.proxy.$Proxy13.selectOne(Unknown Source)at org.mybatis.spring.SqlSessionTemplate.selectOne(SqlSessionTemplate.java:165)at org.apache.ibatis.binding.MapperMethod.execute(MapperMethod.java:69)at org.apache.ibatis.binding.MapperProxy.invoke(MapperProxy.java:53)at com.sun.proxy.$Proxy14.queryById(Unknown Source)at org.seckill.dao.SeckillDaoTest.queryById(SeckillDaoTest.java:32)at sun.reflect.NativeMethodAccessorImpl.invoke0(Native Method)at sun.reflect.NativeMethodAccessorImpl.invoke(NativeMethodAccessorImpl.java:62)at sun.reflect.DelegatingMethodAccessorImpl.invoke(DelegatingMethodAccessorImpl.java:43)at java.lang.reflect.Method.invoke(Method.java:498)at org.junit.runners.model.FrameworkMethod$1.runReflectiveCall(FrameworkMethod.java:47)at org.junit.internal.runners.model.ReflectiveCallable.run(ReflectiveCallable.java:12)at org.junit.runners.model.FrameworkMethod.invokeExplosively(FrameworkMethod.java:44)at org.junit.internal.runners.statements.InvokeMethod.evaluate(InvokeMethod.java:17)at org.springframework.test.context.junit4.statements.RunBeforeTestMethodCallbacks.evaluate(RunBeforeTestMethodCallbacks.java:73)at org.springframework.test.context.junit4.statements.RunAfterTestMethodCallbacks.evaluate(RunAfterTestMethodCallbacks.java:82)at org.springframework.test.context.junit4.statements.SpringRepeat.evaluate(SpringRepeat.java:73)at org.junit.runners.ParentRunner.runLeaf(ParentRunner.java:271)at org.springframework.test.context.junit4.SpringJUnit4ClassRunner.runChild(SpringJUnit4ClassRunner.java:224)at org.springframework.test.context.junit4.SpringJUnit4ClassRunner.runChild(SpringJUnit4ClassRunner.java:83)at org.junit.runners.ParentRunner$3.run(ParentRunner.java:238)at org.junit.runners.ParentRunner$1.schedule(ParentRunner.java:63)at org.junit.runners.ParentRunner.runChildren(ParentRunner.java:236)at org.junit.runners.ParentRunner.access$000(ParentRunner.java:53)at org.junit.runners.ParentRunner$2.evaluate(ParentRunner.java:229)at org.springframework.test.context.junit4.statements.RunBeforeTestClassCallbacks.evaluate(RunBeforeTestClassCallbacks.java:61)at org.springframework.test.context.junit4.statements.RunAfterTestClassCallbacks.evaluate(RunAfterTestClassCallbacks.java:68)at org.junit.runners.ParentRunner.run(ParentRunner.java:309)at org.springframework.test.context.junit4.SpringJUnit4ClassRunner.run(SpringJUnit4ClassRunner.java:163)at org.junit.runner.JUnitCore.run(JUnitCore.java:160)at com.intellij.junit4.JUnit4IdeaTestRunner.startRunnerWithArgs(JUnit4IdeaTestRunner.java:68)at com.intellij.rt.execution.junit.IdeaTestRunner$Repeater.startRunnerWithArgs(IdeaTestRunner.java:51)at com.intellij.rt.execution.junit.JUnitStarter.prepareStreamsAndStart(JUnitStarter.java:237)at com.intellij.rt.execution.junit.JUnitStarter.main(JUnitStarter.java:70)at sun.reflect.NativeMethodAccessorImpl.invoke0(Native Method)at sun.reflect.NativeMethodAccessorImpl.invoke(NativeMethodAccessorImpl.java:62)at sun.reflect.DelegatingMethodAccessorImpl.invoke(DelegatingMethodAccessorImpl.java:43)at java.lang.reflect.Method.invoke(Method.java:498)at com.intellij.rt.execution.application.AppMain.main(AppMain.java:147)

然而出现这些原因就是:
错误的jdbc.properties

driver=com.mysql.jdbc.Driver
url=jdbc:mysql://localhost:3306/seckill?useUnicode=true&characterEncoding=utf-8
username=root
password=root

spring-dao.xml 配置如下

    <!-- 基本属性 url、user、password -->    <property name="jdbcUrl" value="${url}" />    <property name="user" value="${username}" />    <property name="password" value="${password}" />    <!--c3p0私有属性-->    <property name="maxPoolSize" value="30"/>    <property name="minPoolSize" value="10"/>    <!--关闭连接后不自动commit-->    <property name="autoCommitOnClose" value="false"/>    <!--获取连接超时时间-->    <property name="checkoutTimeout" value="1000"/>    <!--当获取连接失败重试次数-->    <property name="acquireRetryAttempts" value="2"/></bean>

然而官网提供的配置是:

    <property name="driverClass" value="${jdbc.driver}"/>    <property name="jdbcUrl" value="${jdbc.url}"/>    <property name="user" value="${jdbc.username}"/>    <property name="password" value="${jdbc.password}"/>    <!--c3p0连接池的私有属性-->    <property name="maxPoolSize" value="30"/>    <property name="minPoolSize" value="10"/>    <!--关闭连接后不自动commit-->    <property name="autoCommitOnClose" value="false"/>      <!--获取连接超时时间-->   <property name="checkoutTimeout" value="1000"/>     <!--当获取连接失败重试次数-->    <property name="acquireRetryAttempts" value="2"/></bean>

而正确的jdbc.properties是:

jdbc.driver=com.mysql.jdbc.Driver
jdbc.url=jdbc:mysql://localhost/seckill?useUnicode=true&characterEncoding=utf-8
jdbc.username=root
jdbc.password=root

最后还是我们要多去翻看spring官方文档，毕竟权威性高！

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