Error querying database. Cause: java.lang.NullPointerException .The error occurred while handlin
问题描述:今天在复习mybatis的时候,自己查询练习遇到一个错误,十分无语错误信息如下org.apache.ibatis.exceptions.PersistenceException:### Error querying database.Cause: java.lang.NullPointerException### The error may exist in com/hegong/dao
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问题描述:
今天在复习mybatis的时候,自己查询练习遇到一个错误,十分无语
错误信息如下
org.apache.ibatis.exceptions.PersistenceException:
### Error querying database. Cause: java.lang.NullPointerException
### The error may exist in com/hegong/dao/IUserDao.xml
### The error may involve com.hegong.dao.IUserDao.findOneToOne
### The error occurred while handling results
### SQL: SELECT u.*,a.id as aid,a.uid,a.money FROM user u,account a WHERE u.id = a.UID
### Cause: java.lang.NullPointerException
at org.apache.ibatis.exceptions.ExceptionFactory.wrapException(ExceptionFactory.java:30)
at org.apache.ibatis.session.defaults.DefaultSqlSession.selectList(DefaultSqlSession.java:150)
at org.apache.ibatis.session.defaults.DefaultSqlSession.selectList(DefaultSqlSession.java:141)
at org.apache.ibatis.binding.MapperMethod.executeForMany(MapperMethod.java:137)
at org.apache.ibatis.binding.MapperMethod.execute(MapperMethod.java:75)
at org.apache.ibatis.binding.MapperProxy.invoke(MapperProxy.java:59)
at com.sun.proxy.$Proxy7.findOneToOne(Unknown Source)
at com.hegong.test.UserTest.test2(UserTest.java:45)
at java.base/jdk.internal.reflect.NativeMethodAccessorImpl.invoke0(Native Method)
at java.base/jdk.internal.reflect.NativeMethodAccessorImpl.invoke(NativeMethodAccessorImpl.java:62)
at java.base/jdk.internal.reflect.DelegatingMethodAccessorImpl.invoke(DelegatingMethodAccessorImpl.java:43)
at java.base/java.lang.reflect.Method.invoke(Method.java:564)
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.junit.internal.runners.statements.RunBefores.evaluate(RunBefores.java:26)
at org.junit.internal.runners.statements.RunAfters.evaluate(RunAfters.java:27)
at org.junit.runners.ParentRunner.runLeaf(ParentRunner.java:271)
at org.junit.runners.BlockJUnit4ClassRunner.runChild(BlockJUnit4ClassRunner.java:70)
at org.junit.runners.BlockJUnit4ClassRunner.runChild(BlockJUnit4ClassRunner.java:50)
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$2.evaluate(ParentRunner.java:229)
at org.junit.runners.ParentRunner.run(ParentRunner.java:309)
at org.junit.runner.JUnitCore.run(JUnitCore.java:160)
at com.intellij.junit4.JUnit4IdeaTestRunner.startRunnerWithArgs(JUnit4IdeaTestRunner.java:68)
at com.intellij.rt.junit.IdeaTestRunner$Repeater.startRunnerWithArgs(IdeaTestRunner.java:33)
at com.intellij.rt.junit.JUnitStarter.prepareStreamsAndStart(JUnitStarter.java:230)
at com.intellij.rt.junit.JUnitStarter.main(JUnitStarter.java:58)
Caused by: java.lang.NullPointerException
原因分析:
其实错误信息里也说了查询数据库时出现错误,出现了空指针异常,这个错误发生在处理结果集封装的时候,报错信息也提示了错误可能出现的位置,然后我就一直找啊一直找怎么也找不到,,真实挺无语的,之能怪自己基础不熟,还眼拙
我的SqlMapConfig.xml
对应接口的配置文件
问题就处在了这里
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