将具有 NULL 值的本机查询结果转换为 POJO答案

【问题标题】：Converting a native query result having NULL values to a POJO将具有 NULL 值的本机查询结果转换为 POJO
【发布时间】：2020-05-06 12:10:36
【问题描述】：

我已经实施了这篇文章中的解决方案 https://stackoverflow.com/a/13013323/10944013

该解决方案仅适用于具有非空值的本机查询结果。我已经描述了这个解决方案失败的案例

@SqlResultSetMapping(name="POJOClassMapping",
classes={
      @ConstructorResult
      (    
        targetClass=POJOClass.class,
        columns= {
                @ColumnResult(name="name", type=String.class),
                @ColumnResult(name="marks", type=int.class),
                @ColumnResult(name="DateOFBirth", type=String.class)
               }
      )
    }
)


public class POJOClass
{
    private String name;

    private int marks;

    private String DateOFBirth;

    public POJOClass()
    {
    }

    public POJOClass(String name, int marks, String dateOFBirth) {

        this.name = name;
        this.marks = marks;
        DateOFBirth = dateOFBirth;
    }

    public String getName() {
        return name;
    }

    public void setName(String name) {
        this.name = name;
    }

    public int getMarks() {
        return marks;
    }

    public void setMarks(int marks) {
        this.marks = marks;
    }

    public String getDateOFBirth() {
        return DateOFBirth;
    }

    public void setDateOFBirth(String dateOFBirth) {
        DateOFBirth = dateOFBirth;
    }

}

我的桌子是这样的：

+---------+-------+-------------+---------+
| Name    | Marks | DateOFBirth | RollNum |
+---------+-------+-------------+---------+
| SomeXYZ | 10    | Null        | 36      |
| SomeQWE | 20    | 01-3-1990   | 43      |
+---------+-------+-------------+---------+

我的查询是

select name,marks,dateOfBirth from myTable where name = "SomeXYZ"

本例中的 dateOfBirth 为空值。因此我得到了java.lang.IllegalArgumentException: null。由于带有参数的 POJO 类构造函数有一个参数为 null。下面是抛出的异常

java.lang.IllegalArgumentException: null
    at sun.reflect.NativeConstructorAccessorImpl.newInstance0(Native Method) ~[?:1.8.0_144]
    at sun.reflect.NativeConstructorAccessorImpl.newInstance(NativeConstructorAccessorImpl.java:62) ~[?:1.8.0_144]
    at sun.reflect.DelegatingConstructorAccessorImpl.newInstance(DelegatingConstructorAccessorImpl.java:45) ~[?:1.8.0_144]
    at java.lang.reflect.Constructor.newInstance(Constructor.java:423) ~[?:1.8.0_144]
    at org.hibernate.loader.custom.ConstructorResultColumnProcessor.extract(ConstructorResultColumnProcessor.java:61) ~[hibernate-core-5.2.14.Final.jar:5.2.14.Final]
    at org.hibernate.loader.custom.ResultRowProcessor.buildResultRow(ResultRowProcessor.java:83) ~[hibernate-core-5.2.14.Final.jar:5.2.14.Final]
    at org.hibernate.loader.custom.ResultRowProcessor.buildResultRow(ResultRowProcessor.java:60) ~[hibernate-core-5.2.14.Final.jar:5.2.14.Final]
    at org.hibernate.loader.custom.CustomLoader.getResultColumnOrRow(CustomLoader.java:409) ~[hibernate-core-5.2.14.Final.jar:5.2.14.Final]
    at org.hibernate.loader.Loader.getRowFromResultSet(Loader.java:761) ~[hibernate-core-5.2.14.Final.jar:5.2.14.Final]
    at org.hibernate.loader.Loader.processResultSet(Loader.java:991) ~[hibernate-core-5.2.14.Final.jar:5.2.14.Final]
    at org.hibernate.loader.Loader.doQuery(Loader.java:949) ~[hibernate-core-5.2.14.Final.jar:5.2.14.Final]
    at org.hibernate.loader.Loader.doQueryAndInitializeNonLazyCollections(Loader.java:341) ~[hibernate-core-5.2.14.Final.jar:5.2.14.Final]
    at org.hibernate.loader.Loader.doList(Loader.java:2692) ~[hibernate-core-5.2.14.Final.jar:5.2.14.Final]
    at org.hibernate.loader.Loader.doList(Loader.java:2675) ~[hibernate-core-5.2.14.Final.jar:5.2.14.Final]
    at org.hibernate.loader.Loader.listIgnoreQueryCache(Loader.java:2507) ~[hibernate-core-5.2.14.Final.jar:5.2.14.Final]
    at org.hibernate.loader.Loader.list(Loader.java:2502) ~[hibernate-core-5.2.14.Final.jar:5.2.14.Final]
    at org.hibernate.loader.custom.CustomLoader.list(CustomLoader.java:335) ~[hibernate-core-5.2.14.Final.jar:5.2.14.Final]
    at org.hibernate.internal.SessionImpl.listCustomQuery(SessionImpl.java:2161) ~[hibernate-core-5.2.14.Final.jar:5.2.14.Final]
    at org.hibernate.internal.AbstractSharedSessionContract.list(AbstractSharedSessionContract.java:1016) ~[hibernate-core-5.2.14.Final.jar:5.2.14.Final]
    at org.hibernate.query.internal.NativeQueryImpl.doList(NativeQueryImpl.java:152) ~[hibernate-core-5.2.14.Final.jar:5.2.14.Final]
    at org.hibernate.query.internal.AbstractProducedQuery.list(AbstractProducedQuery.java:1414) ~[hibernate-core-5.2.14.Final.jar:5.2.14.Final]
    at org.hibernate.query.Query.getResultList(Query.java:146) ~[hibernate-core-5.2.14.Final.jar:5.2.14.Final]
    at com.manh.optimizationportal.LoadAnalyzerCommon.LoadAnalyzerCommonRepository.GetLARecCustCommmitData(LoadAnalyzerCommonRepository.java:69) ~[classes/:?]
    at com.manh.optimizationportal.LoadAnalyzerCommon.LoadAnalyzerCommonRepository$$FastClassBySpringCGLIB$$7fd38196.invoke(<generated>) ~[classes/:?]
    at org.springframework.cglib.proxy.MethodProxy.invoke(MethodProxy.java:204) ~[spring-core-5.0.4.RELEASE.jar:5.0.4.RELEASE]
    at org.springframework.aop.framework.CglibAopProxy$CglibMethodInvocation.invokeJoinpoint(CglibAopProxy.java:747) ~[spring-aop-5.0.4.RELEASE.jar:5.0.4.RELEASE]
    at org.springframework.aop.framework.ReflectiveMethodInvocation.proceed(ReflectiveMethodInvocation.java:163) ~[spring-aop-5.0.4.RELEASE.jar:5.0.4.RELEASE]
    at org.springframework.dao.support.PersistenceExceptionTranslationInterceptor.invoke(PersistenceExceptionTranslationInterceptor.java:139) ~[spring-tx-5.0.4.RELEASE.jar:5.0.4.RELEASE]
    at org.springframework.aop.framework.ReflectiveMethodInvocation.proceed(ReflectiveMethodInvocation.java:185) ~[spring-aop-5.0.4.RELEASE.jar:5.0.4.RELEASE]
    at org.springframework.aop.framework.CglibAopProxy$DynamicAdvisedInterceptor.intercept(CglibAopProxy.java:689) ~[spring-aop-5.0.4.RELEASE.jar:5.0.4.RELEASE]
    at com.manh.optimizationportal.LoadAnalyzerCommon.LoadAnalyzerCommonRepository$$EnhancerBySpringCGLIB$$7f35b549.GetLARecCustCommmitData(<generated>) ~[classes/:?]
    at com.manh.optimizationportal.LoadAnalyzerCommon.LoadAnalyzerCommonService.getLARecCustCommmitData(LoadAnalyzerCommonService.java:46) ~[classes/:?]
    at com.manh.optimizationportal.LoadAnalyzerCommon.LoadAnalyzerCommonController.getBookedOutCount(LoadAnalyzerCommonController.java:51) ~[classes/:?]
    at sun.reflect.NativeMethodAccessorImpl.invoke0(Native Method) ~[?:1.8.0_144]
    at sun.reflect.NativeMethodAccessorImpl.invoke(NativeMethodAccessorImpl.java:62) ~[?:1.8.0_144]
    at sun.reflect.DelegatingMethodAccessorImpl.invoke(DelegatingMethodAccessorImpl.java:43) ~[?:1.8.0_144]
    at java.lang.reflect.Method.invoke(Method.java:498) ~[?:1.8.0_144]
    at org.springframework.web.method.support.InvocableHandlerMethod.doInvoke(InvocableHandlerMethod.java:209) ~[spring-web-5.0.4.RELEASE.jar:5.0.4.RELEASE]
    at org.springframework.web.method.support.InvocableHandlerMethod.invokeForRequest(InvocableHandlerMethod.java:136) ~[spring-web-5.0.4.RELEASE.jar:5.0.4.RELEASE]
    at org.springframework.web.servlet.mvc.method.annotation.ServletInvocableHandlerMethod.invokeAndHandle(ServletInvocableHandlerMethod.java:102) ~[spring-webmvc-5.0.4.RELEASE.jar:5.0.4.RELEASE]
    at org.springframework.web.servlet.mvc.method.annotation.RequestMappingHandlerAdapter.invokeHandlerMethod(RequestMappingHandlerAdapter.java:870) ~[spring-webmvc-5.0.4.RELEASE.jar:5.0.4.RELEASE]
    at org.springframework.web.servlet.mvc.method.annotation.RequestMappingHandlerAdapter.handleInternal(RequestMappingHandlerAdapter.java:776) ~[spring-webmvc-5.0.4.RELEASE.jar:5.0.4.RELEASE]
    at org.springframework.web.servlet.mvc.method.AbstractHandlerMethodAdapter.handle(AbstractHandlerMethodAdapter.java:87) ~[spring-webmvc-5.0.4.RELEASE.jar:5.0.4.RELEASE]
    at org.springframework.web.servlet.DispatcherServlet.doDispatch(DispatcherServlet.java:991) ~[spring-webmvc-5.0.4.RELEASE.jar:5.0.4.RELEASE]
    at org.springframework.web.servlet.DispatcherServlet.doService(DispatcherServlet.java:925) ~[spring-webmvc-5.0.4.RELEASE.jar:5.0.4.RELEASE]
    at org.springframework.web.servlet.FrameworkServlet.processRequest(FrameworkServlet.java:978) ~[spring-webmvc-5.0.4.RELEASE.jar:5.0.4.RELEASE]
    at org.springframework.web.servlet.FrameworkServlet.doGet(FrameworkServlet.java:870) ~[spring-webmvc-5.0.4.RELEASE.jar:5.0.4.RELEASE]
    at javax.servlet.http.HttpServlet.service(HttpServlet.java:635) ~[tomcat-embed-core-8.5.28.jar:8.5.28]
    at org.springframework.web.servlet.FrameworkServlet.service(FrameworkServlet.java:855) ~[spring-webmvc-5.0.4.RELEASE.jar:5.0.4.RELEASE]
    at javax.servlet.http.HttpServlet.service(HttpServlet.java:742) ~[tomcat-embed-core-8.5.28.jar:8.5.28]
    at org.apache.catalina.core.ApplicationFilterChain.internalDoFilter(ApplicationFilterChain.java:231) ~[tomcat-embed-core-8.5.28.jar:8.5.28]
    at org.apache.catalina.core.ApplicationFilterChain.doFilter(ApplicationFilterChain.java:166) ~[tomcat-embed-core-8.5.28.jar:8.5.28]
    at org.apache.tomcat.websocket.server.WsFilter.doFilter(WsFilter.java:52) ~[tomcat-embed-websocket-8.5.28.jar:8.5.28]
    at org.apache.catalina.core.ApplicationFilterChain.internalDoFilter(ApplicationFilterChain.java:193) ~[tomcat-embed-core-8.5.28.jar:8.5.28]
    at org.apache.catalina.core.ApplicationFilterChain.doFilter(ApplicationFilterChain.java:166) ~[tomcat-embed-core-8.5.28.jar:8.5.28]
    at org.springframework.web.filter.RequestContextFilter.doFilterInternal(RequestContextFilter.java:99) ~[spring-web-5.0.4.RELEASE.jar:5.0.4.RELEASE]
    at org.springframework.web.filter.OncePerRequestFilter.doFilter(OncePerRequestFilter.java:107) ~[spring-web-5.0.4.RELEASE.jar:5.0.4.RELEASE]
    at org.apache.catalina.core.ApplicationFilterChain.internalDoFilter(ApplicationFilterChain.java:193) ~[tomcat-embed-core-8.5.28.jar:8.5.28]
    at org.apache.catalina.core.ApplicationFilterChain.doFilter(ApplicationFilterChain.java:166) ~[tomcat-embed-core-8.5.28.jar:8.5.28]
    at org.springframework.web.filter.HttpPutFormContentFilter.doFilterInternal(HttpPutFormContentFilter.java:109) ~[spring-web-5.0.4.RELEASE.jar:5.0.4.RELEASE]
    at org.springframework.web.filter.OncePerRequestFilter.doFilter(OncePerRequestFilter.java:107) ~[spring-web-5.0.4.RELEASE.jar:5.0.4.RELEASE]
    at org.apache.catalina.core.ApplicationFilterChain.internalDoFilter(ApplicationFilterChain.java:193) ~[tomcat-embed-core-8.5.28.jar:8.5.28]
    at org.apache.catalina.core.ApplicationFilterChain.doFilter(ApplicationFilterChain.java:166) ~[tomcat-embed-core-8.5.28.jar:8.5.28]
    at org.springframework.web.filter.HiddenHttpMethodFilter.doFilterInternal(HiddenHttpMethodFilter.java:81) ~[spring-web-5.0.4.RELEASE.jar:5.0.4.RELEASE]
    at org.springframework.web.filter.OncePerRequestFilter.doFilter(OncePerRequestFilter.java:107) ~[spring-web-5.0.4.RELEASE.jar:5.0.4.RELEASE]
    at org.apache.catalina.core.ApplicationFilterChain.internalDoFilter(ApplicationFilterChain.java:193) ~[tomcat-embed-core-8.5.28.jar:8.5.28]
    at org.apache.catalina.core.ApplicationFilterChain.doFilter(ApplicationFilterChain.java:166) ~[tomcat-embed-core-8.5.28.jar:8.5.28]
    at org.springframework.web.filter.CharacterEncodingFilter.doFilterInternal(CharacterEncodingFilter.java:200) ~[spring-web-5.0.4.RELEASE.jar:5.0.4.RELEASE]
    at org.springframework.web.filter.OncePerRequestFilter.doFilter(OncePerRequestFilter.java:107) ~[spring-web-5.0.4.RELEASE.jar:5.0.4.RELEASE]
    at org.apache.catalina.core.ApplicationFilterChain.internalDoFilter(ApplicationFilterChain.java:193) ~[tomcat-embed-core-8.5.28.jar:8.5.28]
    at org.apache.catalina.core.ApplicationFilterChain.doFilter(ApplicationFilterChain.java:166) ~[tomcat-embed-core-8.5.28.jar:8.5.28]
    at org.apache.catalina.core.StandardWrapperValve.invoke(StandardWrapperValve.java:199) [tomcat-embed-core-8.5.28.jar:8.5.28]
    at org.apache.catalina.core.StandardContextValve.invoke(StandardContextValve.java:96) [tomcat-embed-core-8.5.28.jar:8.5.28]
    at org.apache.catalina.authenticator.AuthenticatorBase.invoke(AuthenticatorBase.java:496) [tomcat-embed-core-8.5.28.jar:8.5.28]
    at org.apache.catalina.core.StandardHostValve.invoke(StandardHostValve.java:140) [tomcat-embed-core-8.5.28.jar:8.5.28]
    at org.apache.catalina.valves.ErrorReportValve.invoke(ErrorReportValve.java:81) [tomcat-embed-core-8.5.28.jar:8.5.28]
    at org.apache.catalina.core.StandardEngineValve.invoke(StandardEngineValve.java:87) [tomcat-embed-core-8.5.28.jar:8.5.28]
    at org.apache.catalina.connector.CoyoteAdapter.service(CoyoteAdapter.java:342) [tomcat-embed-core-8.5.28.jar:8.5.28]
    at org.apache.coyote.http11.Http11Processor.service(Http11Processor.java:803) [tomcat-embed-core-8.5.28.jar:8.5.28]
    at org.apache.coyote.AbstractProcessorLight.process(AbstractProcessorLight.java:66) [tomcat-embed-core-8.5.28.jar:8.5.28]
    at org.apache.coyote.AbstractProtocol$ConnectionHandler.process(AbstractProtocol.java:790) [tomcat-embed-core-8.5.28.jar:8.5.28]
    at org.apache.tomcat.util.net.NioEndpoint$SocketProcessor.doRun(NioEndpoint.java:1459) [tomcat-embed-core-8.5.28.jar:8.5.28]
    at org.apache.tomcat.util.net.SocketProcessorBase.run(SocketProcessorBase.java:49) [tomcat-embed-core-8.5.28.jar:8.5.28]
    at java.util.concurrent.ThreadPoolExecutor.runWorker(ThreadPoolExecutor.java:1149) [?:1.8.0_144]
    at java.util.concurrent.ThreadPoolExecutor$Worker.run(ThreadPoolExecutor.java:624) [?:1.8.0_144]
    at org.apache.tomcat.util.threads.TaskThread$WrappingRunnable.run(TaskThread.java:61) [tomcat-embed-core-8.5.28.jar:8.5.28]
    at java.lang.Thread.run(Thread.java:748) [?:1.8.0_144]

【问题讨论】：

添加你的@SqlResultSetMapping
@AdyJunior 我已经编辑了帖子。
我试图找到错误，但我找不到。它非常疯狂....因此，尝试在构造函数和字段类型中将标记出现类型 -> type=int.class 更改为 type=Integer.class 并将“int 标记”更改为“整数标记”。引发该异常的另一种方法是将日期转换为字符串。然后尝试将 dateOfBirth 类型从 String 更改为 Date，就像我上面提到的标记归档一样。
你能重现同样的错误吗？
@AdyJunior 我尝试更改数据类型仍然没有用。

标签： java spring hibernate spring-boot spring-data-jpa

【解决方案1】：

抛出错误的类表明这不是特别是 JPA/Hibernate 问题，而是创建运行时实例时的一般 Java 问题。对于上面的代码和日志，您似乎正在尝试这个

整数（空）-> 整数

将空的Integer 实例转换为原始int。如果它是一个非空值，这会起作用，因为 Java 会为您执行 unboxing。但由于它是一个空值，Java 无法将其转换为原始 int。因此，它给出了IllegalArgumentException。对于SqlResultSetMapping 列，也可能存在其他用户案例，也会发生此异常。为了避免这种情况

明确提及类型，例如@ColumnResult(name = "count", type = Integer.class
对于 POJO 字段，使用 Class(Integer) 而不是原语 (int)。

【讨论】：

实际上我发布了 cmets 说这是问题所在。感谢您发布此内容。