org.apache.ibatis.exceptions.PersistenceException:
Error querying database. Cause: org.apache.ibatis.executor.ExecutorException: Error creating lazy proxy. Cause: java.lang.NullPointerException: Cannot invoke “java.lang.reflect.AccessibleObject.setAccessible(boolean)” because “ao” is null
The error may exist in com/test/mapper/StudentsMapper.xml
The error may involve com.test.mapper.StudentsMapper.selectStudentsAndGrade2
The error occurred while handling results
SQL: select * from students
Cause: org.apache.ibatis.executor.ExecutorException: Error creating lazy proxy. Cause: java.lang.NullPointerException: Cannot invoke “java.lang.reflect.AccessibleObject.setAccessible(boolean)” because “ao” is null
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.session.defaults.DefaultSqlSession.selectList(DefaultSqlSession.java:136)
at com.test.dao.StudentsDao.selectStudentsAndGrade2(StudentsDao.java:34)
at com.test.junit.TestStudentsDao.testSelectStudentsAndGrade2(TestStudentsDao.java:29)
at java.base/jdk.internal.reflect.NativeMethodAccessorImpl.invoke0(Native Method)
at java.base/jdk.internal.reflect.NativeMethodAccessorImpl.invoke(NativeMethodAccessorImpl.java:78)
at java.base/jdk.internal.reflect.DelegatingMethodAccessorImpl.invoke(DelegatingMethodAccessorImpl.java:43)
at java.base/java.lang.reflect.Method.invoke(Method.java:567)
at org.junit.runners.model.FrameworkMethod$1.runReflectiveCall(FrameworkMethod.java:59)
at org.junit.internal.runners.model.ReflectiveCallable.run(ReflectiveCallable.java:12)
at org.junit.runners.model.FrameworkMethod.invokeExplosively(FrameworkMethod.java:56)
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.runners.ParentRunner$3.evaluate(ParentRunner.java:306)
at org.junit.runners.BlockJUnit4ClassRunner$1.evaluate(BlockJUnit4ClassRunner.java:100)
at org.junit.runners.ParentRunner.runLeaf(ParentRunner.java:366)
at org.junit.runners.BlockJUnit4ClassRunner.runChild(BlockJUnit4ClassRunner.java:103)
at org.junit.runners.BlockJUnit4ClassRunner.runChild(BlockJUnit4ClassRunner.java:63)
at org.junit.runners.ParentRunner$4.run(ParentRunner.java:331)
at org.junit.runners.ParentRunner$1.schedule(ParentRunner.java:79)
at org.junit.runners.ParentRunner.runChildren(ParentRunner.java:329)
at org.junit.runners.ParentRunner.access$100(ParentRunner.java:66)
at org.junit.runners.ParentRunner$2.evaluate(ParentRunner.java:293)
at org.junit.runners.ParentRunner$3.evaluate(ParentRunner.java:306)
at org.junit.runners.ParentRunner.run(ParentRunner.java:413)
at org.eclipse.jdt.internal.junit4.runner.JUnit4TestReference.run(JUnit4TestReference.java:93)
at org.eclipse.jdt.internal.junit.runner.TestExecution.run(TestExecution.java:40)
at org.eclipse.jdt.internal.junit.runner.RemoteTestRunner.runTests(RemoteTestRunner.java:529)
at org.eclipse.jdt.internal.junit.runner.RemoteTestRunner.runTests(RemoteTestRunner.java:756)
at org.eclipse.jdt.internal.junit.runner.RemoteTestRunner.run(RemoteTestRunner.java:452)
at org.eclipse.jdt.internal.junit.runner.RemoteTestRunner.main(RemoteTestRunner.java:210)
Caused by: org.apache.ibatis.executor.ExecutorException: Error creating lazy proxy. Cause: java.lang.NullPointerException: Cannot invoke “java.lang.reflect.AccessibleObject.setAccessible(boolean)” because “ao” is null
at org.apache.ibatis.executor.loader.javassist.JavassistProxyFactory.crateProxy(JavassistProxyFactory.java:96)
at org.apache.ibatis.executor.loader.javassist.JavassistProxyFactory$EnhancedResultObjectProxyImpl.createProxy(JavassistProxyFactory.java:125)
at org.apache.ibatis.executor.loader.javassist.JavassistProxyFactory.createProxy(JavassistProxyFactory.java:61)
at org.apache.ibatis.executor.resultset.DefaultResultSetHandler.createResultObject(DefaultResultSetHandler.java:600)
at org.apache.ibatis.executor.resultset.DefaultResultSetHandler.getRowValue(DefaultResultSetHandler.java:396)
at org.apache.ibatis.executor.resultset.DefaultResultSetHandler.handleRowValuesForSimpleResultMap(DefaultResultSetHandler.java:355)
at org.apache.ibatis.executor.resultset.DefaultResultSetHandler.handleRowValues(DefaultResultSetHandler.java:330)
at org.apache.ibatis.executor.resultset.DefaultResultSetHandler.handleResultSet(DefaultResultSetHandler.java:303)
at org.apache.ibatis.executor.resultset.DefaultResultSetHandler.handleResultSets(DefaultResultSetHandler.java:196)
at org.apache.ibatis.executor.statement.PreparedStatementHandler.query(PreparedStatementHandler.java:64)
at org.apache.ibatis.executor.statement.RoutingStatementHandler.query(RoutingStatementHandler.java:79)
at org.apache.ibatis.executor.SimpleExecutor.doQuery(SimpleExecutor.java:63)
at org.apache.ibatis.executor.BaseExecutor.queryFromDatabase(BaseExecutor.java:326)
at org.apache.ibatis.executor.BaseExecutor.query(BaseExecutor.java:156)
at org.apache.ibatis.executor.CachingExecutor.query(CachingExecutor.java:109)
at org.apache.ibatis.executor.CachingExecutor.query(CachingExecutor.java:83)
at org.apache.ibatis.session.defaults.DefaultSqlSession.selectList(DefaultSqlSession.java:148)
… 31 more
Caused by: java.lang.NullPointerException: Cannot invoke “java.lang.reflect.AccessibleObject.setAccessible(boolean)” because “ao” is null
at org.apache.ibatis.javassist.util.proxy.SecurityActions.setAccessible(SecurityActions.java:103)
at org.apache.ibatis.javassist.util.proxy.DefineClassHelper.toClass3(DefineClassHelper.java:151)
at org.apache.ibatis.javassist.util.proxy.DefineClassHelper.toClass2(DefineClassHelper.java:134)
at org.apache.ibatis.javassist.util.proxy.DefineClassHelper.toClass(DefineClassHelper.java:95)
at org.apache.ibatis.javassist.util.proxy.FactoryHelper.toClass(FactoryHelper.java:131)
at org.apache.ibatis.javassist.util.proxy.ProxyFactory.createClass3(ProxyFactory.java:530)
at org.apache.ibatis.javassist.util.proxy.ProxyFactory.createClass2(ProxyFactory.java:515)
at org.apache.ibatis.javassist.util.proxy.ProxyFactory.createClass1(ProxyFactory.java:451)
at org.apache.ibatis.javassist.util.proxy.ProxyFactory.createClass(ProxyFactory.java:422)
at org.apache.ibatis.javassist.util.proxy.ProxyFactory.create(ProxyFactory.java:698)
at org.apache.ibatis.executor.loader.javassist.JavassistProxyFactory.crateProxy(JavassistProxyFactory.java:94)
… 47 more
出现的问题：
解决办法：
Mybatis3.4.6换成了3.5.3
