java.lang.IllegalArgumentException: Result Maps collection does not contain value for java.lang.Integer

今天做springmvc+mybatis+spring的项目的时候发现了一个异常。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

解决方法为：

mapper.xml有配置问题。

错误的配置：

    <!-- 不配置详细的属性，它的名称必须和结果集的列名一致 -->
    <resultMap type="com.hzwealth.pojo.User" id="userRM"></resultMap>
    
    <!-- 带条件查询 -->
    <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>

正确的代码为:

<!-- 不配置详细的属性，它的名称必须和结果集的列名一致 -->
    <resultMap type="com.hzwealth.pojo.User" id="userRM"></resultMap>
    
    <!-- 带条件查询 -->
    <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改为resultType，因为这是返回类型。

解释：

MyBatis中在查询进行select映射的时候，返回类型可以用resultType，也可以用resultMap，resultType是直接表示返回类型的，而resultMap则是对外部ResultMap的引用，但是resultType跟resultMap不能同时存在。
在MyBatis进行查询映射时，其实查询出来的每一个属性都是放在一个对应的Map里面的，其中键是属性名，值则是其对应的值。
①当提供的返回类型属性是resultType时，MyBatis会将Map里面的键值对取出赋给resultType所指定的对象对应的属性。所以其实MyBatis的每一个查询映射的返回类型都是ResultMap，只是当提供的返回类型属性是resultType的时候，MyBatis对自动的给把对应的值赋给resultType所指定对象的属性。
②当提供的返回类型是resultMap时，因为Map不能很好表示领域模型，就需要自己再进一步的把它转化为对应的对象，这常常在复杂查询中很有作用。
上面的解释来自https://zhidao.baidu.com/question/1367837349687326659.html
有错误的地方还请大家指正！

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