Spring+MyBatis 错误：org.mybatis.spring.MyBatisSystemException: nested exception is org.apache.ibatis.b

╰+哭是因爲堅強的太久メ 2021-09-14 12:26 266阅读 0赞

今天用SSM框架做一个项目的时候，在进行简单的测试，发现一个错误，而这个坑在我毕设的时候遇到一次忘记了，这回要记下来。

### org.mybatis.spring.MyBatisSystemException: nested exception is org.apache.ibatis.binding.BindingException: Parameter 'groupName' not   found. Available parameters are \[0, 1, param1, param2\] ###

at org.mybatis.spring.MyBatisExceptionTranslator.translateExceptionIfPossible(MyBatisExceptionTranslator.java:79) at org.mybatis.spring.SqlSessionTemplate$SqlSessionInterceptor.invoke(SqlSessionTemplate.java:447) at com.sun.proxy.$Proxy19.update(Unknown Source) at org.mybatis.spring.SqlSessionTemplate.update(SqlSessionTemplate.java:295) at org.apache.ibatis.binding.MapperMethod.execute(MapperMethod.java:62) at org.apache.ibatis.binding.MapperProxy.invoke(MapperProxy.java:53) at com.sun.proxy.$Proxy20.updateByPrimaryKey(Unknown Source) at com.user.group.service.GroupService.updateByPrimaryKey(GroupService.java:38) at TestOne.selectUsersInGroup(TestOne.java:54) at sun.reflect.NativeMethodAccessorImpl.invoke0(Native Method) at sun.reflect.NativeMethodAccessorImpl.invoke(NativeMethodAccessorImpl.java:62) at sun.reflect.DelegatingMethodAccessorImpl.invoke(DelegatingMethodAccessorImpl.java:43) at java.lang.reflect.Method.invoke(Method.java:497) 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.springframework.test.context.junit4.statements.RunBeforeTestMethodCallbacks.evaluate(RunBeforeTestMethodCallbacks.java:75) at org.springframework.test.context.junit4.statements.RunAfterTestMethodCallbacks.evaluate(RunAfterTestMethodCallbacks.java:86) at org.springframework.test.context.junit4.statements.SpringRepeat.evaluate(SpringRepeat.java:84) at org.junit.runners.ParentRunner.runLeaf(ParentRunner.java:325) at org.springframework.test.context.junit4.SpringJUnit4ClassRunner.runChild(SpringJUnit4ClassRunner.java:252) at org.springframework.test.context.junit4.SpringJUnit4ClassRunner.runChild(SpringJUnit4ClassRunner.java:94) 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$2.evaluate(ParentRunner.java:268) at org.springframework.test.context.junit4.statements.RunBeforeTestClassCallbacks.evaluate(RunBeforeTestClassCallbacks.java:61) at org.springframework.test.context.junit4.statements.RunAfterTestClassCallbacks.evaluate(RunAfterTestClassCallbacks.java:70) at org.junit.runners.ParentRunner.run(ParentRunner.java:363) at org.springframework.test.context.junit4.SpringJUnit4ClassRunner.run(SpringJUnit4ClassRunner.java:191) at org.junit.runner.JUnitCore.run(JUnitCore.java:137) at com.intellij.junit4.JUnit4IdeaTestRunner.startRunnerWithArgs(JUnit4IdeaTestRunner.java:117) at com.intellij.junit4.JUnit4IdeaTestRunner.startRunnerWithArgs(JUnit4IdeaTestRunner.java:42) at com.intellij.rt.execution.junit.JUnitStarter.prepareStreamsAndStart(JUnitStarter.java:262) at com.intellij.rt.execution.junit.JUnitStarter.main(JUnitStarter.java:84) at sun.reflect.NativeMethodAccessorImpl.invoke0(Native Method) at sun.reflect.NativeMethodAccessorImpl.invoke(NativeMethodAccessorImpl.java:62) at sun.reflect.DelegatingMethodAccessorImpl.invoke(DelegatingMethodAccessorImpl.java:43) at java.lang.reflect.Method.invoke(Method.java:497) at com.intellij.rt.execution.application.AppMain.main(AppMain.java:147) Caused by: org.apache.ibatis.binding.BindingException: Parameter 'groupName' not found. Available parameters are [0, 1, param1, param2] at org.apache.ibatis.binding.MapperMethod$ParamMap.get(MapperMethod.java:195) at org.apache.ibatis.reflection.wrapper.MapWrapper.get(MapWrapper.java:45) at org.apache.ibatis.reflection.MetaObject.getValue(MetaObject.java:122) at org.apache.ibatis.scripting.defaults.DefaultParameterHandler.setParameters(DefaultParameterHandler.java:79) at org.apache.ibatis.executor.statement.PreparedStatementHandler.parameterize(PreparedStatementHandler.java:93) at org.apache.ibatis.executor.statement.RoutingStatementHandler.parameterize(RoutingStatementHandler.java:64) at org.apache.ibatis.executor.SimpleExecutor.prepareStatement(SimpleExecutor.java:86) at org.apache.ibatis.executor.SimpleExecutor.doUpdate(SimpleExecutor.java:49) at org.apache.ibatis.executor.BaseExecutor.update(BaseExecutor.java:117) at org.apache.ibatis.executor.CachingExecutor.update(CachingExecutor.java:76) at sun.reflect.NativeMethodAccessorImpl.invoke0(Native Method) at sun.reflect.NativeMethodAccessorImpl.invoke(NativeMethodAccessorImpl.java:62) at sun.reflect.DelegatingMethodAccessorImpl.invoke(DelegatingMethodAccessorImpl.java:43) at java.lang.reflect.Method.invoke(Method.java:497) at org.apache.ibatis.plugin.Plugin.invoke(Plugin.java:63) at com.sun.proxy.$Proxy26.update(Unknown Source) at org.apache.ibatis.session.defaults.DefaultSqlSession.update(DefaultSqlSession.java:198) at sun.reflect.NativeMethodAccessorImpl.invoke0(Native Method) at sun.reflect.NativeMethodAccessorImpl.invoke(NativeMethodAccessorImpl.java:62) at sun.reflect.DelegatingMethodAccessorImpl.invoke(DelegatingMethodAccessorImpl.java:43) at java.lang.reflect.Method.invoke(Method.java:497) at org.mybatis.spring.SqlSessionTemplate$SqlSessionInterceptor.invoke(SqlSessionTemplate.java:434) ... 40 more

void updateByPrimaryKey( String groupId, String groupName);

经测试应该是忘了使用@Param。当只有一个参数时，Mapper中可以不使用，应该使用如下：

void updateByPrimaryKey(@Param("groupId") String groupId,@Param("groupName") String groupName);

这样就可以解决了。

原理：

mybatis首先会根据 **MapperMethod.java** 经过下面方法来转换参数：

public Object convertArgsToSqlCommandParam(Object[] args) {
      final int paramCount = params.size();
      if (args == null || paramCount == 0) {
        return null;
      } else if (!hasNamedParameters && paramCount == 1) {
        return args[params.keySet().iterator().next()];
      } else {
        final Map<String, Object> param = new ParamMap<Object>();
        int i = 0;
        for (Map.Entry<Integer, String> entry : params.entrySet()) {
          param.put(entry.getValue(), args[entry.getKey()]);
          // issue #71, add param names as param1, param2...but ensure backward compatibility
          final String genericParamName = "param" + String.valueOf(i + 1);
          if (!param.containsKey(genericParamName)) {
            param.put(genericParamName, args[entry.getKey()]);
          }
          i++;
        }
        return param;
      }
    }

1.  入参为`null`或没有时，参数转换为`null`
2.  没有使用`@Param`注解并且只有一个参数时，返回这一个参数
3.  使用了`@Param`注解或有多个参数时，将参数转换为`Map`[1][]类型，并且还根据参数顺序存储了key为param1,param2的参数。

建议有多个入参的时候通过 `@Param` 指定参数名

[1]: https://blog.csdn.net/isea533/article/details/44002219#fn:1