MyBatis的TooManyResultsException异常的解决办法

今日再开发遇到了这样的一个异常：Expected one result (or null) to be returned by selectOne(), but found: 2

详细的异常信息如下：

2017-03-31 15:44:24,640 ERROR method:com.baikeyang.bapi.modules.user.service.impl.LoginServiceImpl.login(LoginServiceImpl.java:156) - 用户登录时发生异常
org.mybatis.spring.MyBatisSystemException: nested exception is org.apache.ibatis.exceptions.TooManyResultsException: Expected one result (or null) to be returned by selectOne(), but found: 2
	at org.mybatis.spring.MyBatisExceptionTranslator.translateExceptionIfPossible(MyBatisExceptionTranslator.java:76)
	at org.mybatis.spring.SqlSessionTemplate$SqlSessionInterceptor.invoke(SqlSessionTemplate.java:399)
	at com.sun.proxy.$Proxy13.selectOne(Unknown Source)
	at org.mybatis.spring.SqlSessionTemplate.selectOne(SqlSessionTemplate.java:165)
	at org.apache.ibatis.binding.MapperMethod.execute(MapperMethod.java:63)
	at org.apache.ibatis.binding.MapperProxy.invoke(MapperProxy.java:43)
	at com.sun.proxy.$Proxy14.selectAlarmCountData(Unknown Source)
	at com.baikeyang.bapi.modules.alarm.service.impl.AlarmServiceImpl.getAlarmCountData(AlarmServiceImpl.java:25)
	at com.baikeyang.bapi.modules.user.service.impl.LoginServiceImpl.getAlarmCountData(LoginServiceImpl.java:185)
	at com.baikeyang.bapi.modules.user.service.impl.LoginServiceImpl.login(LoginServiceImpl.java:131)
	at com.baikeyang.bapi.web.controller.LoginController.login(LoginController.java:39)
	at sun.reflect.GeneratedMethodAccessor103.invoke(Unknown Source)
	at sun.reflect.DelegatingMethodAccessorImpl.invoke(DelegatingMethodAccessorImpl.java:25)
	at java.lang.reflect.Method.invoke(Method.java:597)
	at org.springframework.web.method.support.InvocableHandlerMethod.doInvoke(InvocableHandlerMethod.java:221)
	at org.springframework.web.method.support.InvocableHandlerMethod.invokeForRequest(InvocableHandlerMethod.java:137)
	at org.springframework.web.servlet.mvc.method.annotation.ServletInvocableHandlerMethod.invokeAndHandle(ServletInvocableHandlerMethod.java:110)
	at org.springframework.web.servlet.mvc.method.annotation.RequestMappingHandlerAdapter.invokeHandleMethod(RequestMappingHandlerAdapter.java:776)
	at org.springframework.web.servlet.mvc.method.annotation.RequestMappingHandlerAdapter.handleInternal(RequestMappingHandlerAdapter.java:705)
	at org.springframework.web.servlet.mvc.method.AbstractHandlerMethodAdapter.handle(AbstractHandlerMethodAdapter.java:85)
	at org.springframework.web.servlet.DispatcherServlet.doDispatch(DispatcherServlet.java:959)
	at org.springframework.web.servlet.DispatcherServlet.doService(DispatcherServlet.java:893)
	at org.springframework.web.servlet.FrameworkServlet.processRequest(FrameworkServlet.java:967)
	at org.springframework.web.servlet.FrameworkServlet.doPost(FrameworkServlet.java:869)
	at javax.servlet.http.HttpServlet.service(HttpServlet.java:643)
	at org.springframework.web.servlet.FrameworkServlet.service(FrameworkServlet.java:843)
	at javax.servlet.http.HttpServlet.service(HttpServlet.java:723)
	at org.apache.catalina.core.ApplicationFilterChain.internalDoFilter(ApplicationFilterChain.java:290)
	at org.apache.catalina.core.ApplicationFilterChain.doFilter(ApplicationFilterChain.java:206)
	at org.springframework.web.filter.HiddenHttpMethodFilter.doFilterInternal(HiddenHttpMethodFilter.java:77)
	at org.springframework.web.filter.OncePerRequestFilter.doFilter(OncePerRequestFilter.java:107)
	at org.apache.catalina.core.ApplicationFilterChain.internalDoFilter(ApplicationFilterChain.java:235)
	at org.apache.catalina.core.ApplicationFilterChain.doFilter(ApplicationFilterChain.java:206)
	at com.baikeyang.bapi.filter.MethodFilter.doFilter(MethodFilter.java:66)
	at org.apache.catalina.core.ApplicationFilterChain.internalDoFilter(ApplicationFilterChain.java:235)
	at org.apache.catalina.core.ApplicationFilterChain.doFilter(ApplicationFilterChain.java:206)
	at org.springframework.web.filter.CharacterEncodingFilter.doFilterInternal(CharacterEncodingFilter.java:85)
	at org.springframework.web.filter.OncePerRequestFilter.doFilter(OncePerRequestFilter.java:107)
	at org.apache.catalina.core.ApplicationFilterChain.internalDoFilter(ApplicationFilterChain.java:235)
	at org.apache.catalina.core.ApplicationFilterChain.doFilter(ApplicationFilterChain.java:206)
	at org.apache.catalina.core.StandardWrapperValve.invoke(StandardWrapperValve.java:233)
	at org.apache.catalina.core.StandardContextValve.invoke(StandardContextValve.java:191)
	at org.apache.catalina.core.StandardHostValve.invoke(StandardHostValve.java:127)
	at org.apache.catalina.valves.ErrorReportValve.invoke(ErrorReportValve.java:103)
	at org.apache.catalina.core.StandardEngineValve.invoke(StandardEngineValve.java:109)
	at org.apache.catalina.connector.CoyoteAdapter.service(CoyoteAdapter.java:293)
	at org.apache.coyote.http11.Http11AprProcessor.process(Http11AprProcessor.java:879)
	at org.apache.coyote.http11.Http11AprProtocol$Http11ConnectionHandler.process(Http11AprProtocol.java:610)
	at org.apache.tomcat.util.net.AprEndpoint$Worker.run(AprEndpoint.java:1777)
	at java.lang.Thread.run(Thread.java:662)
Caused by: org.apache.ibatis.exceptions.TooManyResultsException: Expected one result (or null) to be returned by selectOne(), but found: 2
	at org.apache.ibatis.session.defaults.DefaultSqlSession.selectOne(DefaultSqlSession.java:66)
	at sun.reflect.GeneratedMethodAccessor89.invoke(Unknown Source)
	at sun.reflect.DelegatingMethodAccessorImpl.invoke(DelegatingMethodAccessorImpl.java:25)
	at java.lang.reflect.Method.invoke(Method.java:597)
	at org.mybatis.spring.SqlSessionTemplate$SqlSessionInterceptor.invoke(SqlSessionTemplate.java:386)
	... 48 more

从上面的异常信息，可以了解到下面两种情况：

1.你想查询一条数据，但返回两条数据：

2.你想查询多条数据，但是前台限制只能查询一条

(1) 检查自己的数据sql语句写对没有（关于mybaties的sql操作自己百度）

(2) 查看mybaties的返回值（resultType或resultMap），可以返回list，map等数据

(3)  dao层接口要与mybaties中返回值和接收值都要保持一致

例：返回map数据

返回多条数据是多个Map，多个Map放在List中用List<Map<String,String>>接收返回数据

Mybatis返回的Map是这样的一种格式：Map<字段名称，字段值>

一个Map<字段名，字段值>对象代表一行数据

原解决方法博文地址：http://www.cnblogs.com/zcleilei/p/6245617.html