今天做springmvc+mybatis+spring的項目的時候發現了一個異常。如下：
org.apache.ibatis.builder.IncompleteElementException: Could not find result map java.lang.Integer at org.apache.ibatis.builder.MapperBuilderAssistant.setStatementResultMap(MapperBuilderAssistant.java:346) at org.apache.ibatis.builder.MapperBuilderAssistant.addMappedStatement(MapperBuilderAssistant.java:284) at org.apache.ibatis.builder.xml.XMLStatementBuilder.parseStatementNode(XMLStatementBuilder.java:107) at org.apache.ibatis.session.Configuration.buildAllStatements(Configuration.java:698) at org.apache.ibatis.session.Configuration.hasStatement(Configuration.java:668) at org.apache.ibatis.session.Configuration.hasStatement(Configuration.java:663) at org.apache.ibatis.binding.MapperMethod$SqlCommand.<init>(MapperMethod.java:180) at org.apache.ibatis.binding.MapperMethod.<init>(MapperMethod.java:43) at org.apache.ibatis.binding.MapperProxy.cachedMapperMethod(MapperProxy.java:58) at org.apache.ibatis.binding.MapperProxy.invoke(MapperProxy.java:51) at $Proxy38.findUser(Unknown Source) at com.hzwealth.service.UserService.getByUserName(UserService.java:45) at com.hzwealth.lender.shiro.AuthRealm.doGetAuthenticationInfo(AuthRealm.java:63) at org.apache.shiro.realm.AuthenticatingRealm.getAuthenticationInfo(AuthenticatingRealm.java:568) at org.apache.shiro.authc.pam.ModularRealmAuthenticator.doSingleRealmAuthentication(ModularRealmAuthenticator.java:180) at org.apache.shiro.authc.pam.ModularRealmAuthenticator.doAuthenticate(ModularRealmAuthenticator.java:267) at org.apache.shiro.authc.AbstractAuthenticator.authenticate(AbstractAuthenticator.java:198) at org.apache.shiro.mgt.AuthenticatingSecurityManager.authenticate(AuthenticatingSecurityManager.java:106) at org.apache.shiro.mgt.DefaultSecurityManager.login(DefaultSecurityManager.java:270) at org.apache.shiro.subject.support.DelegatingSubject.login(DelegatingSubject.java:256) at com.hzwealth.controller.UserController.doLogin(UserController.java:65) 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:601) 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:647) at org.springframework.web.servlet.FrameworkServlet.service(FrameworkServlet.java:842) at javax.servlet.http.HttpServlet.service(HttpServlet.java:728) at org.apache.catalina.core.ApplicationFilterChain.internalDoFilter(ApplicationFilterChain.java:305) at org.apache.catalina.core.ApplicationFilterChain.doFilter(ApplicationFilterChain.java:210) at org.apache.tomcat.websocket.server.WsFilter.doFilter(WsFilter.java:51) at org.apache.catalina.core.ApplicationFilterChain.internalDoFilter(ApplicationFilterChain.java:243) at org.apache.catalina.core.ApplicationFilterChain.doFilter(ApplicationFilterChain.java:210) 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:243) at org.apache.catalina.core.ApplicationFilterChain.doFilter(ApplicationFilterChain.java:210) at org.apache.shiro.web.servlet.ProxiedFilterChain.doFilter(ProxiedFilterChain.java:61) at org.apache.shiro.web.servlet.AdviceFilter.executeChain(AdviceFilter.java:108) at org.apache.shiro.web.servlet.AdviceFilter.doFilterInternal(AdviceFilter.java:137) at org.apache.shiro.web.servlet.OncePerRequestFilter.doFilter(OncePerRequestFilter.java:125) at org.apache.shiro.web.servlet.ProxiedFilterChain.doFilter(ProxiedFilterChain.java:66) at org.apache.shiro.web.servlet.AbstractShiroFilter.executeChain(AbstractShiroFilter.java:449) at org.apache.shiro.web.servlet.AbstractShiroFilter$1.call(AbstractShiroFilter.java:365) at org.apache.shiro.subject.support.SubjectCallable.doCall(SubjectCallable.java:90) at org.apache.shiro.subject.support.SubjectCallable.call(SubjectCallable.java:83) at org.apache.shiro.subject.support.DelegatingSubject.execute(DelegatingSubject.java:383) at org.apache.shiro.web.servlet.AbstractShiroFilter.doFilterInternal(AbstractShiroFilter.java:362) at org.apache.shiro.web.servlet.OncePerRequestFilter.doFilter(OncePerRequestFilter.java:125) at org.springframework.web.filter.DelegatingFilterProxy.invokeDelegate(DelegatingFilterProxy.java:344) at org.springframework.web.filter.DelegatingFilterProxy.doFilter(DelegatingFilterProxy.java:261) at org.apache.catalina.core.ApplicationFilterChain.internalDoFilter(ApplicationFilterChain.java:243) at org.apache.catalina.core.ApplicationFilterChain.doFilter(ApplicationFilterChain.java:210) at org.apache.catalina.core.StandardWrapperValve.invoke(StandardWrapperValve.java:222) at org.apache.catalina.core.StandardContextValve.invoke(StandardContextValve.java:123) at org.apache.catalina.authenticator.AuthenticatorBase.invoke(AuthenticatorBase.java:502) at org.apache.catalina.core.StandardHostValve.invoke(StandardHostValve.java:171) at org.apache.catalina.valves.ErrorReportValve.invoke(ErrorReportValve.java:100) at org.apache.catalina.valves.AccessLogValve.invoke(AccessLogValve.java:953) at org.apache.catalina.core.StandardEngineValve.invoke(StandardEngineValve.java:118) at org.apache.catalina.connector.CoyoteAdapter.service(CoyoteAdapter.java:408) at org.apache.coyote.http11.AbstractHttp11Processor.process(AbstractHttp11Processor.java:1041) at org.apache.coyote.AbstractProtocol$AbstractConnectionHandler.process(AbstractProtocol.java:603) at org.apache.tomcat.util.net.JIoEndpoint$SocketProcessor.run(JIoEndpoint.java:312) at java.util.concurrent.ThreadPoolExecutor.runWorker(ThreadPoolExecutor.java:1110) at java.util.concurrent.ThreadPoolExecutor$Worker.run(ThreadPoolExecutor.java:603) at java.lang.Thread.run(Thread.java:722) Caused by: java.lang.IllegalArgumentException: Result Maps collection does not contain value for java.lang.Integer at org.apache.ibatis.session.Configuration$StrictMap.get(Configuration.java:797) at org.apache.ibatis.session.Configuration.getResultMap(Configuration.java:550) at org.apache.ibatis.builder.MapperBuilderAssistant.setStatementResultMap(MapperBuilderAssistant.java:344) ... 76 more
解決方法為：
mapper.xml有配置問題。
錯誤的配置：
<!-- 不配置詳細的屬性，它的名稱必須和結果集的列名一致 -->
<resultMap type="com.hzwealth.pojo.User" id="userRM"></resultMap>
<!-- 帶條件查詢 -->
<select id="findUser" parameterType="java.util.Map" resultMap="userRM">
select * from tb_user where 1=1
<if test="id!=null">
and id=#{id}
</if>
<if test="username != null">
and username=#{username}
</if>
<if test="password != null">
and password=#{password}
</if>
<if test="phone!=null">
and phone=#{phone}
</if>
<if test="email!=null">
and email=#{email}
</if>
</select>
<select id="checkUser" parameterType="java.util.Map" resultMap="java.lang.Integer">
select count(*) from tb_user where 1=1
<if test="username != null">
and username=#{username}
</if>
</select>
正確的代碼為:
<!-- 不配置詳細的屬性，它的名稱必須和結果集的列名一致 -->
<resultMap type="com.hzwealth.pojo.User" id="userRM"></resultMap>
<!-- 帶條件查詢 -->
<select id="findUser" parameterType="java.util.Map" resultMap="userRM">
select * from tb_user where 1=1
<if test="id!=null">
and id=#{id}
</if>
<if test="username != null">
and username=#{username}
</if>
<if test="password != null">
and password=#{password}
</if>
<if test="phone!=null">
and phone=#{phone}
</if>
<if test="email!=null">
and email=#{email}
</if>
</select>
<select id="checkUser" parameterType="java.util.Map" resultType="java.lang.Integer">
select count(*) from tb_user where 1=1
<if test="username != null">
and username=#{username}
</if>
</select>
意思就是把resultMap改為resultType，因為這是返回類型。
解釋：
MyBatis中在查詢進行select映射的時候，返回類型可以用resultType，也可以用resultMap，resultType是直接表示返回類型的，而resultMap則是對外部ResultMap的引用，但是resultType跟resultMap不能同時存在。
在MyBatis進行查詢映射時，其實查詢出來的每一個屬性都是放在一個對應的Map里面的，其中鍵是屬性名，值則是其對應的值。
①當提供的返回類型屬性是resultType時，MyBatis會將Map里面的鍵值對取出賦給resultType所指定的對象對應的屬性。所以其實MyBatis的每一個查詢映射的返回類型都是ResultMap，只是當提供的返回類型屬性是resultType的時候，MyBatis對自動的給把對應的值賦給resultType所指定對象的屬性。
②當提供的返回類型是resultMap時，因為Map不能很好表示領域模型，就需要自己再進一步的把它轉化為對應的對象，這常常在復雜查詢中很有作用。
上面的解釋來自https://zhidao.baidu.com/question/1367837349687326659.html
有錯誤的地方還請大家指正！
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