Mybatis collection查询集合属性报错的解决方案

Mybatis collection查询集合属性报错

错误日志

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									org.springframework.http.converter.HttpMessageConversionException: Type definition error: [simple type, class org.apache.ibatis.executor.loader.javassist.JavassistProxyFactory$EnhancedResultObjectProxyImpl]; nested exception is com.fasterxml.jackson.databind.exc.InvalidDefinitionException: No serializer found for class org.apache.ibatis.executor.loader.javassist.JavassistProxyFactory$EnhancedResultObjectProxyImpl and no properties discovered to create BeanSerializer (to avoid exception, disable SerializationFeature.FAIL_ON_EMPTY_BEANS) (through reference chain: com.hexagonsi.sandtablebackendservice.controller.viewModel.ReturnResult["data"]->java.util.ArrayList[0]->com.hexagonsi.sandtablebackendservice.model.AreaBean_$$_jvstc74_0["handler"])

									    at org.springframework.http.converter.json.AbstractJackson2HttpMessageConverter.writeInternal(AbstractJackson2HttpMessageConverter.java:303)

									    at org.springframework.http.converter.AbstractGenericHttpMessageConverter.write(AbstractGenericHttpMessageConverter.java:104)

									    at org.springframework.web.servlet.mvc.method.annotation.AbstractMessageConverterMethodProcessor.writeWithMessageConverters(AbstractMessageConverterMethodProcessor.java:287)

									    at org.springframework.web.servlet.mvc.method.annotation.HttpEntityMethodProcessor.handleReturnValue(HttpEntityMethodProcessor.java:226)

									    at org.springframework.web.method.support.HandlerMethodReturnValueHandlerComposite.handleReturnValue(HandlerMethodReturnValueHandlerComposite.java:82)

									    at org.springframework.web.servlet.mvc.method.annotation.ServletInvocableHandlerMethod.invokeAndHandle(ServletInvocableHandlerMethod.java:124)

									    at org.springframework.web.servlet.mvc.method.annotation.RequestMappingHandlerAdapter.invokeHandlerMethod(RequestMappingHandlerAdapter.java:879)

									    at org.springframework.web.servlet.mvc.method.annotation.RequestMappingHandlerAdapter.handleInternal(RequestMappingHandlerAdapter.java:793)

									    at org.springframework.web.servlet.mvc.method.AbstractHandlerMethodAdapter.handle(AbstractHandlerMethodAdapter.java:87)

									    at org.springframework.web.servlet.DispatcherServlet.doDispatch(DispatcherServlet.java:1040)

									    at org.springframework.web.servlet.DispatcherServlet.doService(DispatcherServlet.java:943)

									    at org.springframework.web.servlet.FrameworkServlet.processRequest(FrameworkServlet.java:1006)

									    at org.springframework.web.servlet.FrameworkServlet.doGet(FrameworkServlet.java:898)

									    at javax.servlet.http.HttpServlet.service(HttpServlet.java:634)

									    at org.springframework.web.servlet.FrameworkServlet.service(FrameworkServlet.java:883)

									    at javax.servlet.http.HttpServlet.service(HttpServlet.java:741)

									    at org.apache.catalina.core.ApplicationFilterChain.internalDoFilter(ApplicationFilterChain.java:231)

									    at org.apache.catalina.core.ApplicationFilterChain.doFilter(ApplicationFilterChain.java:166)

									    at org.apache.tomcat.websocket.server.WsFilter.doFilter(WsFilter.java:53)

									    at org.apache.catalina.core.ApplicationFilterChain.internalDoFilter(ApplicationFilterChain.java:193)

									    at org.apache.catalina.core.ApplicationFilterChain.doFilter(ApplicationFilterChain.java:166)

									    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:387)

									    at org.apache.shiro.web.servlet.AbstractShiroFilter.doFilterInternal(AbstractShiroFilter.java:362)

									    at org.apache.shiro.web.servlet.OncePerRequestFilter.doFilter(OncePerRequestFilter.java:125)

									    at org.apache.catalina.core.ApplicationFilterChain.internalDoFilter(ApplicationFilterChain.java:193)

									    at org.apache.catalina.core.ApplicationFilterChain.doFilter(ApplicationFilterChain.java:166)

									    at org.springframework.web.filter.RequestContextFilter.doFilterInternal(RequestContextFilter.java:100)

									    at org.springframework.web.filter.OncePerRequestFilter.doFilter(OncePerRequestFilter.java:119)

									    at org.apache.catalina.core.ApplicationFilterChain.internalDoFilter(ApplicationFilterChain.java:193)

									    at org.apache.catalina.core.ApplicationFilterChain.doFilter(ApplicationFilterChain.java:166)

									    at org.springframework.web.filter.FormContentFilter.doFilterInternal(FormContentFilter.java:93)

									    at org.springframework.web.filter.OncePerRequestFilter.doFilter(OncePerRequestFilter.java:119)

									    at org.apache.catalina.core.ApplicationFilterChain.internalDoFilter(ApplicationFilterChain.java:193)

									    at org.apache.catalina.core.ApplicationFilterChain.doFilter(ApplicationFilterChain.java:166)

									    at org.springframework.web.filter.CharacterEncodingFilter.doFilterInternal(CharacterEncodingFilter.java:201)

									    at org.springframework.web.filter.OncePerRequestFilter.doFilter(OncePerRequestFilter.java:119)

									    at org.apache.catalina.core.ApplicationFilterChain.internalDoFilter(ApplicationFilterChain.java:193)

									    at org.apache.catalina.core.ApplicationFilterChain.doFilter(ApplicationFilterChain.java:166)

									    at org.apache.catalina.core.StandardWrapperValve.invoke(StandardWrapperValve.java:202)

									    at org.apache.catalina.core.StandardContextValve.invoke(StandardContextValve.java:96)

									    at org.apache.catalina.authenticator.AuthenticatorBase.invoke(AuthenticatorBase.java:541)

									    at org.apache.catalina.core.StandardHostValve.invoke(StandardHostValve.java:139)

									    at org.apache.catalina.valves.ErrorReportValve.invoke(ErrorReportValve.java:92)

									    at org.apache.catalina.core.StandardEngineValve.invoke(StandardEngineValve.java:74)

									    at org.apache.catalina.connector.CoyoteAdapter.service(CoyoteAdapter.java:343)

									    at org.apache.coyote.http11.Http11Processor.service(Http11Processor.java:367)

									    at org.apache.coyote.AbstractProcessorLight.process(AbstractProcessorLight.java:65)

									    at org.apache.coyote.AbstractProtocol$ConnectionHandler.process(AbstractProtocol.java:868)

									    at org.apache.tomcat.util.net.NioEndpoint$SocketProcessor.doRun(NioEndpoint.java:1639)

									    at org.apache.tomcat.util.net.SocketProcessorBase.run(SocketProcessorBase.java:49)

									    at java.util.concurrent.ThreadPoolExecutor.runWorker(ThreadPoolExecutor.java:1142)

									    at java.util.concurrent.ThreadPoolExecutor$Worker.run(ThreadPoolExecutor.java:617)

									    at org.apache.tomcat.util.threads.TaskThread$WrappingRunnable.run(TaskThread.java:61)

									    at java.lang.Thread.run(Thread.java:745)

背景

使用collection查询集合属性数据

排查

如下图，发现在查询数据后，实体类中自动添加了一个“handler”属性，该属性是没有对应的set/get方法

Mybatis collection查询集合属性报错的解决方案

解决方法

在结合属性所在的类上添加注解：转json时，忽略自动产生的handler属性

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									@JsonIgnoreProperties(value = {"handler"})

用以在json序列化时忽略bean中一些不需要转化的属性

MyBatis 包含属性为集合的查询

父实体类

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									public class MerchantsVO {

									    private Integer id;

									    private String name;

									    private List<PaymentAccountVO> paymentAccountList;

									}

关联子查询实体类

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									public class PaymentAccountVO {

									    private Integer id;

									    private Integer merchantsId;

									}

父查询返回结果实体类映射

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									<resultMap id="merchantsResultMap" type="com.entity.vo.MerchantsVO">                

									        <result property="id" column="id"/>

									        <result property="name" column="name"/>

									        <collection property="paymentAccountList" ofType="com.entity.vo.PaymentAccountVO"

									   column="id" select="getPaymentAccountByMerchantsId" fetchType="eager">

									        </collection>

									</resultMap>

									     <collection>标签中的  column="id" ， 对应为父实体类数据库映射字段，用于关联子查询

集合子查询实体类映射

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									<resultMap id="paymentAccountResultMap" type="com.entity.vo.PaymentAccountVO">

									     <!-- 定义这个集合中元素的封装规则 -->

									        <result property="id" column="id"/>

									        <result property="merchantsId" column="merchants_id"/>

									</resultMap>

父查询

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									<select id="getMerchantsVOList" resultMap="merchantsResultMap">

									    SELECT m.* FROM merchants m

									</select>

子查询

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									<select id="getPaymentAccountByMerchantsId" resultMap="paymentAccountResultMap">

									    SELECT * FROM payment_account WHERE merchants_id = #{id}

									</select>