Mybatis遇到的问题

问题：

org.mybatis.spring.MyBatisSystemException: nested exception is org.apache.ibatis.reflection.ReflectionException: There is no getter for property named 'unitId' in 'class java.lang.String'
    at org.mybatis.spring.MyBatisExceptionTranslator.translateExceptionIfPossible(MyBatisExceptionTranslator.java:75)
    at org.mybatis.spring.SqlSessionTemplate$SqlSessionInterceptor.invoke(SqlSessionTemplate.java:371)
    at com.sun.proxy.$Proxy6.selectList(Unknown Source)
    at org.mybatis.spring.SqlSessionTemplate.selectList(SqlSessionTemplate.java:198)
    at org.apache.ibatis.binding.MapperMethod.executeForMany(MapperMethod.java:119)
    at org.apache.ibatis.binding.MapperMethod.execute(MapperMethod.java:63)
    at org.apache.ibatis.binding.MapperProxy.invoke(MapperProxy.java:52)
    at com.sun.proxy.$Proxy11.getUsersByUnitId(Unknown Source)
    at com.thinkPro.steap.db.base.sys.user.UserBase.getUsersByUnitId(UserBase.java:125)
    at com.thinkPro.steap.db.service.sys.user.UserService.getUsersByUnitId(UserService.java:188)
    at com.thinkPro.steap.test.TestUser.testGetUsersByUnitId(TestUser.java:184)
    at sun.reflect.NativeMethodAccessorImpl.invoke0(Native Method)
    at sun.reflect.NativeMethodAccessorImpl.invoke(NativeMethodAccessorImpl.java:57)
    at sun.reflect.DelegatingMethodAccessorImpl.invoke(DelegatingMethodAccessorImpl.java:43)
    at java.lang.reflect.Method.invoke(Method.java:606)
    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$2.evaluate(ParentRunner.java:268)
    at org.junit.runners.ParentRunner.run(ParentRunner.java:363)
    at org.eclipse.jdt.internal.junit4.runner.JUnit4TestReference.run(JUnit4TestReference.java:50)
    at org.eclipse.jdt.internal.junit.runner.TestExecution.run(TestExecution.java:38)
    at org.eclipse.jdt.internal.junit.runner.RemoteTestRunner.runTests(RemoteTestRunner.java:467)
    at org.eclipse.jdt.internal.junit.runner.RemoteTestRunner.runTests(RemoteTestRunner.java:683)
    at org.eclipse.jdt.internal.junit.runner.RemoteTestRunner.run(RemoteTestRunner.java:390)
    at org.eclipse.jdt.internal.junit.runner.RemoteTestRunner.main(RemoteTestRunner.java:197)
Caused by: org.apache.ibatis.reflection.ReflectionException: There is no getter for property named 'unitId' in 'class java.lang.String'
    at org.apache.ibatis.reflection.Reflector.getGetInvoker(Reflector.java:380)
    at org.apache.ibatis.reflection.MetaClass.getGetInvoker(MetaClass.java:170)
    at org.apache.ibatis.reflection.wrapper.BeanWrapper.getBeanProperty(BeanWrapper.java:152)
    at org.apache.ibatis.reflection.wrapper.BeanWrapper.get(BeanWrapper.java:48)
    at org.apache.ibatis.reflection.MetaObject.getValue(MetaObject.java:116)
    at org.apache.ibatis.scripting.xmltags.DynamicContext$ContextMap.get(DynamicContext.java:97)
    at org.apache.ibatis.scripting.xmltags.DynamicContext$ContextAccessor.getProperty(DynamicContext.java:116)
    at org.apache.ibatis.ognl.OgnlRuntime.getProperty(OgnlRuntime.java:1657)
    at org.apache.ibatis.ognl.ASTProperty.getValueBody(ASTProperty.java:92)
    at org.apache.ibatis.ognl.SimpleNode.evaluateGetValueBody(SimpleNode.java:170)
    at org.apache.ibatis.ognl.SimpleNode.getValue(SimpleNode.java:210)
    at org.apache.ibatis.ognl.ASTNotEq.getValueBody(ASTNotEq.java:49)
    at org.apache.ibatis.ognl.SimpleNode.evaluateGetValueBody(SimpleNode.java:170)
    at org.apache.ibatis.ognl.SimpleNode.getValue(SimpleNode.java:210)
    at org.apache.ibatis.ognl.ASTAnd.getValueBody(ASTAnd.java:56)
    at org.apache.ibatis.ognl.SimpleNode.evaluateGetValueBody(SimpleNode.java:170)
    at org.apache.ibatis.ognl.SimpleNode.getValue(SimpleNode.java:210)
    at org.apache.ibatis.ognl.Ognl.getValue(Ognl.java:333)
    at org.apache.ibatis.ognl.Ognl.getValue(Ognl.java:310)
    at org.apache.ibatis.scripting.xmltags.OgnlCache.getValue(OgnlCache.java:45)
    at org.apache.ibatis.scripting.xmltags.ExpressionEvaluator.evaluateBoolean(ExpressionEvaluator.java:32)
    at org.apache.ibatis.scripting.xmltags.IfSqlNode.apply(IfSqlNode.java:33)
    at org.apache.ibatis.scripting.xmltags.MixedSqlNode.apply(MixedSqlNode.java:32)
    at org.apache.ibatis.scripting.xmltags.TrimSqlNode.apply(TrimSqlNode.java:54)
    at org.apache.ibatis.scripting.xmltags.MixedSqlNode.apply(MixedSqlNode.java:32)
    at org.apache.ibatis.scripting.xmltags.DynamicSqlSource.getBoundSql(DynamicSqlSource.java:40)
    at org.apache.ibatis.mapping.MappedStatement.getBoundSql(MappedStatement.java:278)
    at org.apache.ibatis.executor.CachingExecutor.query(CachingExecutor.java:75)
    at org.apache.ibatis.session.defaults.DefaultSqlSession.selectList(DefaultSqlSession.java:108)
    at org.apache.ibatis.session.defaults.DefaultSqlSession.selectList(DefaultSqlSession.java:102)
    at sun.reflect.NativeMethodAccessorImpl.invoke0(Native Method)
    at sun.reflect.NativeMethodAccessorImpl.invoke(NativeMethodAccessorImpl.java:57)
    at sun.reflect.DelegatingMethodAccessorImpl.invoke(DelegatingMethodAccessorImpl.java:43)
    at java.lang.reflect.Method.invoke(Method.java:606)
    at org.mybatis.spring.SqlSessionTemplate$SqlSessionInterceptor.invoke(SqlSessionTemplate.java:358)
    ... 32 more

分析：

那么什么情况下会发生“There is no getter for property named in ‘class java.lang.String’”错误呢？

其实是在这种情况下：

    <select id="getRiskMember" resultMap="BaseResultMap" parameterType="String">
        <include refid="selectMember"/>
        and safetylevel > 1
        and stauts = 1

        <if test="username != null">
            and username = #{username} 
        </if>
    </select>

注意看，是在if test=验证的时候发生的 “There is no getter for property named in ‘class java.lang.String’”，

而并非是and username = #{username} 的时候发生的错误。

解决办法：

  <select id="getRiskMember" resultMap="BaseResultMap" parameterType="String">
        <include refid="selectMember"/>
        and safetylevel > 1
        and stauts = 1

        <if test="_parameter != null">
            and username = #{username} 
        </if>
    </select>