FAQ（18）：org.apache.ibatis.reflection.ReflectionException: Could not set property 'username' of 'clas

场景Mybatis--resultMap的使用BUG：

看LOG：

===============test add!DEBUG 12-18 17:58:54,995 ==>  Preparing: select * from smbms_user u,smbms_role r where u.userName like CONCAT ('%',?,'%') and u.userRole = ? and u.userRole = r.id   (BaseJdbcLogger.java:145) DEBUG 12-18 17:58:55,072 ==> Parameters: mmb(String), 110(Integer)  (BaseJdbcLogger.java:145) org.apache.ibatis.exceptions.PersistenceException: ### Error querying database.  Cause: org.apache.ibatis.reflection.ReflectionException: Could not set property 'username' of 'class com.smbms.entities.User' with value 'mmb02' Cause: org.apache.ibatis.reflection.ReflectionException: There is no setter for property named 'username' in 'class com.smbms.entities.User'### The error may exist in com/smbms/dao/UserMapper.xml### The error may involve com.smbms.dao.UserMapper.getUserLista### The error occurred while handling results### SQL: select * from smbms_user u,smbms_role r       where u.userName like CONCAT ('%',?,'%')       and u.userRole = ? and u.userRole = r.id### Cause: org.apache.ibatis.reflection.ReflectionException: Could not set property 'username' of 'class com.smbms.entities.User' with value 'mmb02' Cause: org.apache.ibatis.reflection.ReflectionException: There is no setter for property named 'username' in 'class com.smbms.entities.User'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:53)at com.sun.proxy.$Proxy4.getUserLista(Unknown Source)at com.smbms.entities.UserTest.test13(UserTest.java:336)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:50)at org.junit.internal.runners.model.ReflectiveCallable.run(ReflectiveCallable.java:12)at org.junit.runners.model.FrameworkMethod.invokeExplosively(FrameworkMethod.java:47)at org.junit.internal.runners.statements.InvokeMethod.evaluate(InvokeMethod.java:17)at org.junit.runners.ParentRunner.runLeaf(ParentRunner.java:325)at org.junit.runners.BlockJUnit4ClassRunner.runChild(BlockJUnit4ClassRunner.java:78)at org.junit.runners.BlockJUnit4ClassRunner.runChild(BlockJUnit4ClassRunner.java:57)at org.junit.runners.ParentRunner$3.run(ParentRunner.java:290)at org.junit.runners.ParentRunner$1.schedule(ParentRunner.java:71)at org.junit.runners.ParentRunner.runChildren(ParentRunner.java:288)at org.junit.runners.ParentRunner.access$000(ParentRunner.java:58)at org.junit.runners.ParentRunner$2.evaluate(ParentRunner.java:268)at org.junit.runners.ParentRunner.run(ParentRunner.java:363)at org.eclipse.jdt.internal.junit4.runner.JUnit4TestReference.run(JUnit4TestReference.java:86)at org.eclipse.jdt.internal.junit.runner.TestExecution.run(TestExecution.java:38)at org.eclipse.jdt.internal.junit.runner.RemoteTestRunner.runTests(RemoteTestRunner.java:459)at org.eclipse.jdt.internal.junit.runner.RemoteTestRunner.runTests(RemoteTestRunner.java:675)at org.eclipse.jdt.internal.junit.runner.RemoteTestRunner.run(RemoteTestRunner.java:382)at org.eclipse.jdt.internal.junit.runner.RemoteTestRunner.main(RemoteTestRunner.java:192)Caused by: org.apache.ibatis.reflection.ReflectionException: Could not set property 'username' of 'class com.smbms.entities.User' with value 'mmb02' Cause: org.apache.ibatis.reflection.ReflectionException: There is no setter for property named 'username' in 'class com.smbms.entities.User'at org.apache.ibatis.reflection.wrapper.BeanWrapper.setBeanProperty(BeanWrapper.java:185)at org.apache.ibatis.reflection.wrapper.BeanWrapper.set(BeanWrapper.java:59)at org.apache.ibatis.reflection.MetaObject.setValue(MetaObject.java:140)at org.apache.ibatis.executor.resultset.DefaultResultSetHandler.applyPropertyMappings(DefaultResultSetHandler.java:438)at org.apache.ibatis.executor.resultset.DefaultResultSetHandler.getRowValue(DefaultResultSetHandler.java:386)at org.apache.ibatis.executor.resultset.DefaultResultSetHandler.handleRowValuesForSimpleResultMap(DefaultResultSetHandler.java:338)at org.apache.ibatis.executor.resultset.DefaultResultSetHandler.handleRowValues(DefaultResultSetHandler.java:313)at org.apache.ibatis.executor.resultset.DefaultResultSetHandler.handleResultSet(DefaultResultSetHandler.java:286)at org.apache.ibatis.executor.resultset.DefaultResultSetHandler.handleResultSets(DefaultResultSetHandler.java:183)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:324)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)... 29 moreCaused by: org.apache.ibatis.reflection.ReflectionException: There is no setter for property named 'username' in 'class com.smbms.entities.User'at org.apache.ibatis.reflection.Reflector.getSetInvoker(Reflector.java:401)at org.apache.ibatis.reflection.MetaClass.getSetInvoker(MetaClass.java:168)at org.apache.ibatis.reflection.wrapper.BeanWrapper.setBeanProperty(BeanWrapper.java:177)... 45 more

解决：因为在User.java中，属性变量配置为private String userName;返回结果集要跟对象属性挂钩！

User.java：private String userName；

原：

<resultMap><result property="username" column="username"/></resultMap>

改：

<resultMap><result property="userName" column="username"/></resultMap>