ssh整合出错经典

   现在好多公司都是用ssh做开发，不管是ssh1还是ssh2,我觉得难度都差不多，和以往开发不同的是我们把数据源交给spring管理，我们使用的数据源是通过依赖注入的。因此在做开发的时候注入不成功也是常有的事情，还有什么数据源配置不合理，都会引发一系列的问题，使用时就要考虑到这些。前几天做开发的时候出现了个异常，把我差点搞死了。下面看下这个异常；

org.hibernate.exception.GenericJDBCException: could not execute query
	at org.hibernate.exception.SQLStateConverter.handledNonSpecificException(SQLStateConverter.java:140)
	at org.hibernate.exception.SQLStateConverter.convert(SQLStateConverter.java:128)
	at org.hibernate.exception.JDBCExceptionHelper.convert(JDBCExceptionHelper.java:66)
	at org.hibernate.loader.Loader.doList(Loader.java:2536)
	at org.hibernate.loader.Loader.listIgnoreQueryCache(Loader.java:2276)
	at org.hibernate.loader.Loader.list(Loader.java:2271)
	at org.hibernate.loader.hql.QueryLoader.list(QueryLoader.java:452)
	at org.hibernate.hql.ast.QueryTranslatorImpl.list(QueryTranslatorImpl.java:363)
	at org.hibernate.engine.query.HQLQueryPlan.performList(HQLQueryPlan.java:196)
	at org.hibernate.impl.SessionImpl.list(SessionImpl.java:1268)
	at org.hibernate.impl.QueryImpl.list(QueryImpl.java:102)
	at org.lxh.impl.ClassBean.findAllClass(ClassBean.java:30)
	at sun.reflect.NativeMethodAccessorImpl.invoke0(Native Method)
	at sun.reflect.NativeMethodAccessorImpl.invoke(Unknown Source)
	at sun.reflect.DelegatingMethodAccessorImpl.invoke(Unknown Source)
	at java.lang.reflect.Method.invoke(Unknown Source)
	at org.springframework.aop.support.AopUtils.invokeJoinpointUsingReflection(AopUtils.java:307)
	at org.springframework.aop.framework.ReflectiveMethodInvocation.invokeJoinpoint(ReflectiveMethodInvocation.java:182)
	at org.springframework.aop.framework.ReflectiveMethodInvocation.proceed(ReflectiveMethodInvocation.java:149)
	at org.springframework.transaction.interceptor.TransactionInterceptor.invoke(TransactionInterceptor.java:106)
	at org.springframework.aop.framework.ReflectiveMethodInvocation.proceed(ReflectiveMethodInvocation.java:171)
	at org.springframework.aop.framework.JdkDynamicAopProxy.invoke(JdkDynamicAopProxy.java:204)
	at $Proxy9.findAllClass(Unknown Source)
	at unittest.Test.getAllClass(Test.java:107)
	at sun.reflect.NativeMethodAccessorImpl.invoke0(Native Method)
	at sun.reflect.NativeMethodAccessorImpl.invoke(Unknown Source)
	at sun.reflect.DelegatingMethodAccessorImpl.invoke(Unknown Source)
	at java.lang.reflect.Method.invoke(Unknown Source)
	at org.junit.runners.model.FrameworkMethod$1.runReflectiveCall(FrameworkMethod.java:44)
	at org.junit.internal.runners.model.ReflectiveCallable.run(ReflectiveCallable.java:15)
	at org.junit.runners.model.FrameworkMethod.invokeExplosively(FrameworkMethod.java:41)
	at org.junit.internal.runners.statements.InvokeMethod.evaluate(InvokeMethod.java:20)
	at org.junit.runners.BlockJUnit4ClassRunner.runChild(BlockJUnit4ClassRunner.java:76)
	at org.junit.runners.BlockJUnit4ClassRunner.runChild(BlockJUnit4ClassRunner.java:50)
	at org.junit.runners.ParentRunner$3.run(ParentRunner.java:193)
	at org.junit.runners.ParentRunner$1.schedule(ParentRunner.java:52)
	at org.junit.runners.ParentRunner.runChildren(ParentRunner.java:191)
	at org.junit.runners.ParentRunner.access$000(ParentRunner.java:42)
	at org.junit.runners.ParentRunner$2.evaluate(ParentRunner.java:184)
	at org.junit.internal.runners.statements.RunBefores.evaluate(RunBefores.java:28)
	at org.junit.runners.ParentRunner.run(ParentRunner.java:236)
	at org.eclipse.jdt.internal.junit4.runner.JUnit4TestReference.run(JUnit4TestReference.java:49)
	at org.eclipse.jdt.internal.junit.runner.TestExecution.run(TestExecution.java:38)
	at org.eclipse.jdt.internal.junit.runner.RemoteTestRunner.runTests(RemoteTestRunner.java:467)
	at org.eclipse.jdt.internal.junit.runner.RemoteTestRunner.runTests(RemoteTestRunner.java:683)
	at org.eclipse.jdt.internal.junit.runner.RemoteTestRunner.run(RemoteTestRunner.java:390)
	at org.eclipse.jdt.internal.junit.runner.RemoteTestRunner.main(RemoteTestRunner.java:197)
Caused by: java.sql.SQLException: Illegal mix of collations (gbk_chinese_ci,IMPLICIT) and (utf8_general_ci,COERCIBLE) for operation '='
	at com.mysql.jdbc.SQLError.createSQLException(SQLError.java:946)
	at com.mysql.jdbc.MysqlIO.checkErrorPacket(MysqlIO.java:2870)
	at com.mysql.jdbc.MysqlIO.sendCommand(MysqlIO.java:1573)
	at com.mysql.jdbc.ServerPreparedStatement.serverExecute(ServerPreparedStatement.java:1169)
	at com.mysql.jdbc.ServerPreparedStatement.executeInternal(ServerPreparedStatement.java:693)
	at com.mysql.jdbc.PreparedStatement.executeQuery(PreparedStatement.java:1266)
	at org.apache.commons.dbcp.DelegatingPreparedStatement.executeQuery(DelegatingPreparedStatement.java:93)
	at org.hibernate.jdbc.AbstractBatcher.getResultSet(AbstractBatcher.java:208)
	at org.hibernate.loader.Loader.getResultSet(Loader.java:1953)
	at org.hibernate.loader.Loader.doQuery(Loader.java:802)
	at org.hibernate.loader.Loader.doQueryAndInitializeNonLazyCollections(Loader.java:274)
	at org.hibernate.loader.Loader.doList(Loader.java:2533)
	... 43 more

“could not execute query”也就是“不能执行查询”，产生这个错误有这么2种情况：1.hql语句有错误。2.数据库编码和所开发的项目使用的编码不一致

知道异常产生的原因，问题就好解决了，对于mysql建议使用GBK编码，这个是最合适不过了。看这个异常的根本原因就是编码不匹配造成的，当数据库的编码是GBK的时候，spring的配置文件应该这么写

 <bean id="dataSource" class="org.apache.commons.dbcp.BasicDataSource"
		destroy-method="close">
		<property name="driverClassName" value="com.mysql.jdbc.Driver" />
		<property name="url"
			value="jdbc:mysql://localhost:3306/design?useUnicode=true&characterEncoding=GBK" />
		<property name="username" value="root" />
		<property name="password" value="123456" />
			<!-- 连接池启动时的初始值 -->
		<property name="initialSize" value="1" />
		<!-- 连接池的最大值 -->
		<property name="maxActive" value="100" />
		<!-- 最大空闲值.当经过一个高峰时间后，连接池可以慢慢将已经用不到的连接慢慢释放一部分，一直减少到maxIdle为止 -->
		<property name="maxIdle" value="30" />
		<!-- 最小空闲值.当空闲的连接数少于阀值时，连接池就会预申请去一些连接，以免洪峰来时来不及申请 -->
		<property name="minIdle" value="1" />
        <property name="maxWait" value="10000" />
	</bean> 

如果characterEncoding设置成了UTF-8，如果你的程序这么写if("tom".equals(你使用hibernate查询出来的数据))，那么这个异常就很有可能产生了，解决的办法就是:

1.把数据库的编码改回来（成功的几率不大）

2.修改配置文件（95%的成功率)

到这里异常解决了，有问题的可以和我交流。