SSM時遇到的異常（5）——TooManyResultsException: Expected one result (or null) to be returned by selectOne(),
阿新 • • 發佈：2019-01-08
JDK1.7+Tomcat7.0+Eclipse+SSM
嚴重: Servlet.service() for servlet [SpringMVC] in context with path [/MVCQ] threw exception [Request processing failed; nested exception is 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] with root cause 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:63) 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.mybatis.spring.SqlSessionTemplate$SqlSessionInterceptor.invoke(SqlSessionTemplate.java:355) at com.sun.proxy.$Proxy14.selectOne(Unknown Source) at org.mybatis.spring.SqlSessionTemplate.selectOne(SqlSessionTemplate.java:160) at org.apache.ibatis.binding.MapperMethod.execute(MapperMethod.java:95) at org.apache.ibatis.binding.MapperProxy.invoke(MapperProxy.java:40) at com.sun.proxy.$Proxy15.empByNameAndPwd(Unknown Source) at com.qiu.service.EmpService.login(EmpService.java:56) at com.qiu.service.EmpService$$FastClassBySpringCGLIB$$f54dc904.invoke(<generated>) at org.springframework.cglib.proxy.MethodProxy.invoke(MethodProxy.java:204) at org.springframework.aop.framework.CglibAopProxy$CglibMethodInvocation.invokeJoinpoint(CglibAopProxy.java:717) at org.springframework.aop.framework.ReflectiveMethodInvocation.proceed(ReflectiveMethodInvocation.java:157) at org.springframework.transaction.interceptor.TransactionInterceptor$1.proceedWithInvocation(TransactionInterceptor.java:99) at org.springframework.transaction.interceptor.TransactionAspectSupport.invokeWithinTransaction(TransactionAspectSupport.java:281) at org.springframework.transaction.interceptor.TransactionInterceptor.invoke(TransactionInterceptor.java:96) at org.springframework.aop.framework.ReflectiveMethodInvocation.proceed(ReflectiveMethodInvocation.java:179) at org.springframework.aop.framework.CglibAopProxy$DynamicAdvisedInterceptor.intercept(CglibAopProxy.java:653) at com.qiu.service.EmpService$$EnhancerBySpringCGLIB$$b12e93a5.login(<generated>) at com.qiu.controller.LoginController.login(LoginController.java:189) 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.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:777) at org.springframework.web.servlet.mvc.method.annotation.RequestMappingHandlerAdapter.handleInternal(RequestMappingHandlerAdapter.java:706) at org.springframework.web.servlet.mvc.method.AbstractHandlerMethodAdapter.handle(AbstractHandlerMethodAdapter.java:85) at org.springframework.web.servlet.DispatcherServlet.doDispatch(DispatcherServlet.java:943) at org.springframework.web.servlet.DispatcherServlet.doService(DispatcherServlet.java:877) at org.springframework.web.servlet.FrameworkServlet.processRequest(FrameworkServlet.java:966) at org.springframework.web.servlet.FrameworkServlet.doPost(FrameworkServlet.java:868) at javax.servlet.http.HttpServlet.service(HttpServlet.java:646) at org.springframework.web.servlet.FrameworkServlet.service(FrameworkServlet.java:842) at javax.servlet.http.HttpServlet.service(HttpServlet.java:727) at org.apache.catalina.core.ApplicationFilterChain.internalDoFilter(ApplicationFilterChain.java:303) at org.apache.catalina.core.ApplicationFilterChain.doFilter(ApplicationFilterChain.java:208) at org.apache.tomcat.websocket.server.WsFilter.doFilter(WsFilter.java:52) at org.apache.catalina.core.ApplicationFilterChain.internalDoFilter(ApplicationFilterChain.java:241) at org.apache.catalina.core.ApplicationFilterChain.doFilter(ApplicationFilterChain.java:208) at org.springframework.web.filter.CharacterEncodingFilter.doFilterInternal(CharacterEncodingFilter.java:88) at org.springframework.web.filter.OncePerRequestFilter.doFilter(OncePerRequestFilter.java:107) at org.apache.catalina.core.ApplicationFilterChain.internalDoFilter(ApplicationFilterChain.java:241) at org.apache.catalina.core.ApplicationFilterChain.doFilter(ApplicationFilterChain.java:208) at org.apache.catalina.core.StandardWrapperValve.invoke(StandardWrapperValve.java:220) at org.apache.catalina.core.StandardContextValve.invoke(StandardContextValve.java:122) at org.apache.catalina.authenticator.AuthenticatorBase.invoke(AuthenticatorBase.java:501) at org.apache.catalina.core.StandardHostValve.invoke(StandardHostValve.java:170) at org.apache.catalina.valves.ErrorReportValve.invoke(ErrorReportValve.java:98) at org.apache.catalina.valves.AccessLogValve.invoke(AccessLogValve.java:950) at org.apache.catalina.core.StandardEngineValve.invoke(StandardEngineValve.java:116) at org.apache.catalina.connector.CoyoteAdapter.service(CoyoteAdapter.java:408) at org.apache.coyote.http11.AbstractHttp11Processor.process(AbstractHttp11Processor.java:1040) at org.apache.coyote.AbstractProtocol$AbstractConnectionHandler.process(AbstractProtocol.java:607) at org.apache.tomcat.util.net.JIoEndpoint$SocketProcessor.run(JIoEndpoint.java:315) at java.util.concurrent.ThreadPoolExecutor.runWorker(Unknown Source) at java.util.concurrent.ThreadPoolExecutor$Worker.run(Unknown Source) at java.lang.Thread.run(Unknown Source)
我都被弄得莫名其妙！！！太多Result導致異常？？？最終，我換個瀏覽器，頁面正常。。。。。。
當然報錯，不可能，無緣無故 T_T ！！！
1.一開始
因為
,
程式碼（list和find沒有合併,也就是"查詢"和"列表"不在同一個方法）:
2.接著
（前提：在合併之前，login頁面和EmpList頁面都是執行正常，只是“當年齡輸入框中沒有輸入值時，點選查詢按鈕會立即報400”這樣的問題）
所以為了不報400、方便，試著將“list”和“find”方法，合併：
擴充套件：SpringMVC的controller向jsp傳遞資料的五種方式詳解
【ModelMap、Map與Model效果差不多，但還是存在區別】
3.再接著
合併之後，我想著先從"登入"頁面轉向"員工列表"頁面，所以我先重新整理，從login.jsp進入，
當我點選“登入”按鈕後，就報這樣的異常！！！接著，把改了的程式碼都“撤消”！！！還是繼續這樣的報錯！！！再接著，我重啟Tomcat幾次，再以相同的方式進去，錯誤繼續顯示出來！！！我重啟Eclipse幾次，再以相同的方式進去，錯誤繼續顯示出來！！！
再再接著，我只能，URL欄，輸入“http://localhost:8080/MVCQ/emp/list”，並沒有跳出異常！！！login頁面沒錯，list（）方法轉向EmpList頁面也沒錯， 我就納悶了，怎麼會這樣，在該瀏覽器（2345加速瀏覽器），換了視窗，再以相同的方式進去，錯誤繼續顯示出來！！！我百度，搜的這些文章，都可以參考，
（1）Spring mvc+mybatis框架下的TooManyResultsException異常【將方法Bean型別改為List<Bean>型別】
（2）
MyBatis報TooManyResultsException: Expected one result to be returned by selectOne()異常【將selectOne方法換成selectList或將多餘（指empName或name相同的）的資料清理掉】
或者
mybatis中的一個異常：org.apache.ibatis.exceptions.TooManyResultsException: Expected one result (or null) to
或者
可是對於我，也就只能看看，卻不能解決我的問題，因為最後：我換其他瀏覽器（谷歌），以相同的方式進去，正常顯示EmpList頁面！！！
SelectOne原始碼學習（異常中顯示的selectOne()函數了解一波）
Mybatis selectOne方法執行sql有資料返回為null【select標籤增加了resultMap屬性】
4.最後的最後
400異常我已解決 【點選藍色字，立馬轉向對應文章】