Spring MVC 在Sping Boot jpa中将Lazy Loaded对象转换为JSON

xe55xuns  于 2022-11-15  发布在  Spring
关注(0)|答案(4)|浏览(134)

我在发送Lazy loaded对象作为JSON以响应Sping Boot 中的REST请求时出错。
当我从浏览器请求获取parentTree并调用get方法获取版本以测试延迟加载并返回版本时，在进程中我得到了下面提供的错误。
以下是我的模型：

  • 父树.java*
@Entity
@Data
@Table(name = "parent_tree_temp")
public class ParentTreeTemp {

    @Id
    private Long id;
    private String name;

    @ManyToOne(fetch = FetchType.LAZY)
    @JoinColumn(name = "version_id")
    private Version versionId;
}
  • . java版本 *
@Entity
@Data
public class Version {
    @Id
    private Long id;
    private String name;

    @Column(name = "gl_type")
    private String glType;

    @Column(name = "version_type")
    private String versionType;

    @Column(name = "effective_date")
    private Date effectiveDate;
}
  • 控制器.java*
@GetMapping("/ParentTree")
    public Version parentTrees() {
        Version v =  parentTreeRepository.findAll().get(0).getVersionId();
        return v;
    }
  • 父树资源库.java*
@Repository
public interface ParentTreeRepository extends JpaRepository<ParentTreeTemp, Long> {
}
  • 错误 *
2019-05-01 16:20:04.818 ERROR 15140 --- [nio-8080-exec-2] o.a.c.c.C.[.[.[/].[dispatcherServlet]    : Servlet.service() for servlet [dispatcherServlet] in context with path [] threw exception [Request processing failed; nested exception is org.springframework.http.converter.HttpMessageConversionException: Type definition error: [simple type, class org.hibernate.proxy.pojo.bytebuddy.ByteBuddyInterceptor]; nested exception is com.fasterxml.jackson.databind.exc.InvalidDefinitionException: No serializer found for class org.hibernate.proxy.pojo.bytebuddy.ByteBuddyInterceptor and no properties discovered to create BeanSerializer (to avoid exception, disable SerializationFeature.FAIL_ON_EMPTY_BEANS) (through reference chain: com.example.redwood.sqlserverapi.model.Version$HibernateProxy$Rwpjov1a["hibernateLazyInitializer"])] with root cause

com.fasterxml.jackson.databind.exc.InvalidDefinitionException: No serializer found for class org.hibernate.proxy.pojo.bytebuddy.ByteBuddyInterceptor and no properties discovered to create BeanSerializer (to avoid exception, disable SerializationFeature.FAIL_ON_EMPTY_BEANS) (through reference chain: com.example.redwood.sqlserverapi.model.Version$HibernateProxy$Rwpjov1a["hibernateLazyInitializer"])
  • 完整错误日志 *
2019-05-01 16:20:04.818 ERROR 15140 --- [nio-8080-exec-2] o.a.c.c.C.[.[.[/].[dispatcherServlet]    : Servlet.service() for servlet [dispatcherServlet] in context with path [] threw exception [Request processing failed; nested exception is org.springframework.http.converter.HttpMessageConversionException: Type definition error: [simple type, class org.hibernate.proxy.pojo.bytebuddy.ByteBuddyInterceptor]; nested exception is com.fasterxml.jackson.databind.exc.InvalidDefinitionException: No serializer found for class org.hibernate.proxy.pojo.bytebuddy.ByteBuddyInterceptor and no properties discovered to create BeanSerializer (to avoid exception, disable SerializationFeature.FAIL_ON_EMPTY_BEANS) (through reference chain: com.example.redwood.sqlserverapi.model.Version$HibernateProxy$Rwpjov1a["hibernateLazyInitializer"])] with root cause

com.fasterxml.jackson.databind.exc.InvalidDefinitionException: No serializer found for class org.hibernate.proxy.pojo.bytebuddy.ByteBuddyInterceptor and no properties discovered to create BeanSerializer (to avoid exception, disable SerializationFeature.FAIL_ON_EMPTY_BEANS) (through reference chain: com.example.redwood.sqlserverapi.model.Version$HibernateProxy$Rwpjov1a["hibernateLazyInitializer"])
    at com.fasterxml.jackson.databind.exc.InvalidDefinitionException.from(InvalidDefinitionException.java:77) ~[jackson-databind-2.9.8.jar:2.9.8]
    at com.fasterxml.jackson.databind.SerializerProvider.reportBadDefinition(SerializerProvider.java:1191) ~[jackson-databind-2.9.8.jar:2.9.8]
    at com.fasterxml.jackson.databind.DatabindContext.reportBadDefinition(DatabindContext.java:313) ~[jackson-databind-2.9.8.jar:2.9.8]
    at com.fasterxml.jackson.databind.ser.impl.UnknownSerializer.failForEmpty(UnknownSerializer.java:71) ~[jackson-databind-2.9.8.jar:2.9.8]
    at com.fasterxml.jackson.databind.ser.impl.UnknownSerializer.serialize(UnknownSerializer.java:33) ~[jackson-databind-2.9.8.jar:2.9.8]
    at com.fasterxml.jackson.databind.ser.BeanPropertyWriter.serializeAsField(BeanPropertyWriter.java:727) ~[jackson-databind-2.9.8.jar:2.9.8]
    at com.fasterxml.jackson.databind.ser.std.BeanSerializerBase.serializeFields(BeanSerializerBase.java:719) ~[jackson-databind-2.9.8.jar:2.9.8]
    at com.fasterxml.jackson.databind.ser.BeanSerializer.serialize(BeanSerializer.java:155) ~[jackson-databind-2.9.8.jar:2.9.8]
    at com.fasterxml.jackson.databind.ser.DefaultSerializerProvider._serialize(DefaultSerializerProvider.java:480) ~[jackson-databind-2.9.8.jar:2.9.8]
    at com.fasterxml.jackson.databind.ser.DefaultSerializerProvider.serializeValue(DefaultSerializerProvider.java:319) ~[jackson-databind-2.9.8.jar:2.9.8]
    at com.fasterxml.jackson.databind.ObjectWriter$Prefetch.serialize(ObjectWriter.java:1396) ~[jackson-databind-2.9.8.jar:2.9.8]
    at com.fasterxml.jackson.databind.ObjectWriter.writeValue(ObjectWriter.java:913) ~[jackson-databind-2.9.8.jar:2.9.8]
    at org.springframework.http.converter.json.AbstractJackson2HttpMessageConverter.writeInternal(AbstractJackson2HttpMessageConverter.java:287) ~[spring-web-5.1.6.RELEASE.jar:5.1.6.RELEASE]
    at org.springframework.http.converter.AbstractGenericHttpMessageConverter.write(AbstractGenericHttpMessageConverter.java:103) ~[spring-web-5.1.6.RELEASE.jar:5.1.6.RELEASE]
    at org.springframework.web.servlet.mvc.method.annotation.AbstractMessageConverterMethodProcessor.writeWithMessageConverters(AbstractMessageConverterMethodProcessor.java:290) ~[spring-webmvc-5.1.6.RELEASE.jar:5.1.6.RELEASE]
    at org.springframework.web.servlet.mvc.method.annotation.RequestResponseBodyMethodProcessor.handleReturnValue(RequestResponseBodyMethodProcessor.java:180) ~[spring-webmvc-5.1.6.RELEASE.jar:5.1.6.RELEASE]
    at org.springframework.web.method.support.HandlerMethodReturnValueHandlerComposite.handleReturnValue(HandlerMethodReturnValueHandlerComposite.java:82) ~[spring-web-5.1.6.RELEASE.jar:5.1.6.RELEASE]
    at org.springframework.web.servlet.mvc.method.annotation.ServletInvocableHandlerMethod.invokeAndHandle(ServletInvocableHandlerMethod.java:119) ~[spring-webmvc-5.1.6.RELEASE.jar:5.1.6.RELEASE]
    at org.springframework.web.servlet.mvc.method.annotation.RequestMappingHandlerAdapter.invokeHandlerMethod(RequestMappingHandlerAdapter.java:892) ~[spring-webmvc-5.1.6.RELEASE.jar:5.1.6.RELEASE]
    at org.springframework.web.servlet.mvc.method.annotation.RequestMappingHandlerAdapter.handleInternal(RequestMappingHandlerAdapter.java:797) ~[spring-webmvc-5.1.6.RELEASE.jar:5.1.6.RELEASE]
    at org.springframework.web.servlet.mvc.method.AbstractHandlerMethodAdapter.handle(AbstractHandlerMethodAdapter.java:87) ~[spring-webmvc-5.1.6.RELEASE.jar:5.1.6.RELEASE]
    at org.springframework.web.servlet.DispatcherServlet.doDispatch(DispatcherServlet.java:1038) ~[spring-webmvc-5.1.6.RELEASE.jar:5.1.6.RELEASE]
    at org.springframework.web.servlet.DispatcherServlet.doService(DispatcherServlet.java:942) ~[spring-webmvc-5.1.6.RELEASE.jar:5.1.6.RELEASE]
    at org.springframework.web.servlet.FrameworkServlet.processRequest(FrameworkServlet.java:1005) ~[spring-webmvc-5.1.6.RELEASE.jar:5.1.6.RELEASE]
    at org.springframework.web.servlet.FrameworkServlet.doGet(FrameworkServlet.java:897) ~[spring-webmvc-5.1.6.RELEASE.jar:5.1.6.RELEASE]
    at javax.servlet.http.HttpServlet.service(HttpServlet.java:634) ~[tomcat-embed-core-9.0.17.jar:9.0.17]
    at org.springframework.web.servlet.FrameworkServlet.service(FrameworkServlet.java:882) ~[spring-webmvc-5.1.6.RELEASE.jar:5.1.6.RELEASE]
    at javax.servlet.http.HttpServlet.service(HttpServlet.java:741) ~[tomcat-embed-core-9.0.17.jar:9.0.17]
    at org.apache.catalina.core.ApplicationFilterChain.internalDoFilter(ApplicationFilterChain.java:231) ~[tomcat-embed-core-9.0.17.jar:9.0.17]
    at org.apache.catalina.core.ApplicationFilterChain.doFilter(ApplicationFilterChain.java:166) ~[tomcat-embed-core-9.0.17.jar:9.0.17]
    at org.apache.tomcat.websocket.server.WsFilter.doFilter(WsFilter.java:53) ~[tomcat-embed-websocket-9.0.17.jar:9.0.17]
    at org.apache.catalina.core.ApplicationFilterChain.internalDoFilter(ApplicationFilterChain.java:193) ~[tomcat-embed-core-9.0.17.jar:9.0.17]
    at org.apache.catalina.core.ApplicationFilterChain.doFilter(ApplicationFilterChain.java:166) ~[tomcat-embed-core-9.0.17.jar:9.0.17]
    at org.springframework.web.filter.RequestContextFilter.doFilterInternal(RequestContextFilter.java:99) ~[spring-web-5.1.6.RELEASE.jar:5.1.6.RELEASE]
    at org.springframework.web.filter.OncePerRequestFilter.doFilter(OncePerRequestFilter.java:107) ~[spring-web-5.1.6.RELEASE.jar:5.1.6.RELEASE]
    at org.apache.catalina.core.ApplicationFilterChain.internalDoFilter(ApplicationFilterChain.java:193) ~[tomcat-embed-core-9.0.17.jar:9.0.17]
    at org.apache.catalina.core.ApplicationFilterChain.doFilter(ApplicationFilterChain.java:166) ~[tomcat-embed-core-9.0.17.jar:9.0.17]
    at org.springframework.web.filter.FormContentFilter.doFilterInternal(FormContentFilter.java:92) ~[spring-web-5.1.6.RELEASE.jar:5.1.6.RELEASE]
    at org.springframework.web.filter.OncePerRequestFilter.doFilter(OncePerRequestFilter.java:107) ~[spring-web-5.1.6.RELEASE.jar:5.1.6.RELEASE]
    at org.apache.catalina.core.ApplicationFilterChain.internalDoFilter(ApplicationFilterChain.java:193) ~[tomcat-embed-core-9.0.17.jar:9.0.17]
    at org.apache.catalina.core.ApplicationFilterChain.doFilter(ApplicationFilterChain.java:166) ~[tomcat-embed-core-9.0.17.jar:9.0.17]
    at org.springframework.web.filter.HiddenHttpMethodFilter.doFilterInternal(HiddenHttpMethodFilter.java:93) ~[spring-web-5.1.6.RELEASE.jar:5.1.6.RELEASE]
    at org.springframework.web.filter.OncePerRequestFilter.doFilter(OncePerRequestFilter.java:107) ~[spring-web-5.1.6.RELEASE.jar:5.1.6.RELEASE]
    at org.apache.catalina.core.ApplicationFilterChain.internalDoFilter(ApplicationFilterChain.java:193) ~[tomcat-embed-core-9.0.17.jar:9.0.17]
    at org.apache.catalina.core.ApplicationFilterChain.doFilter(ApplicationFilterChain.java:166) ~[tomcat-embed-core-9.0.17.jar:9.0.17]
    at org.springframework.web.filter.CharacterEncodingFilter.doFilterInternal(CharacterEncodingFilter.java:200) ~[spring-web-5.1.6.RELEASE.jar:5.1.6.RELEASE]
    at org.springframework.web.filter.OncePerRequestFilter.doFilter(OncePerRequestFilter.java:107) ~[spring-web-5.1.6.RELEASE.jar:5.1.6.RELEASE]
    at org.apache.catalina.core.ApplicationFilterChain.internalDoFilter(ApplicationFilterChain.java:193) ~[tomcat-embed-core-9.0.17.jar:9.0.17]
    at org.apache.catalina.core.ApplicationFilterChain.doFilter(ApplicationFilterChain.java:166) ~[tomcat-embed-core-9.0.17.jar:9.0.17]
    at org.apache.catalina.core.StandardWrapperValve.invoke(StandardWrapperValve.java:200) ~[tomcat-embed-core-9.0.17.jar:9.0.17]
    at org.apache.catalina.core.StandardContextValve.invoke(StandardContextValve.java:96) [tomcat-embed-core-9.0.17.jar:9.0.17]
    at org.apache.catalina.authenticator.AuthenticatorBase.invoke(AuthenticatorBase.java:490) [tomcat-embed-core-9.0.17.jar:9.0.17]
    at org.apache.catalina.core.StandardHostValve.invoke(StandardHostValve.java:139) [tomcat-embed-core-9.0.17.jar:9.0.17]
    at org.apache.catalina.valves.ErrorReportValve.invoke(ErrorReportValve.java:92) [tomcat-embed-core-9.0.17.jar:9.0.17]
    at org.apache.catalina.core.StandardEngineValve.invoke(StandardEngineValve.java:74) [tomcat-embed-core-9.0.17.jar:9.0.17]
    at org.apache.catalina.connector.CoyoteAdapter.service(CoyoteAdapter.java:343) [tomcat-embed-core-9.0.17.jar:9.0.17]
    at org.apache.coyote.http11.Http11Processor.service(Http11Processor.java:408) [tomcat-embed-core-9.0.17.jar:9.0.17]
    at org.apache.coyote.AbstractProcessorLight.process(AbstractProcessorLight.java:66) [tomcat-embed-core-9.0.17.jar:9.0.17]
    at org.apache.coyote.AbstractProtocol$ConnectionHandler.process(AbstractProtocol.java:834) [tomcat-embed-core-9.0.17.jar:9.0.17]
    at org.apache.tomcat.util.net.NioEndpoint$SocketProcessor.doRun(NioEndpoint.java:1415) [tomcat-embed-core-9.0.17.jar:9.0.17]
    at org.apache.tomcat.util.net.SocketProcessorBase.run(SocketProcessorBase.java:49) [tomcat-embed-core-9.0.17.jar:9.0.17]
    at java.util.concurrent.ThreadPoolExecutor.runWorker(ThreadPoolExecutor.java:1149) [na:1.8.0_202]
    at java.util.concurrent.ThreadPoolExecutor$Worker.run(ThreadPoolExecutor.java:624) [na:1.8.0_202]
    at org.apache.tomcat.util.threads.TaskThread$WrappingRunnable.run(TaskThread.java:61) [tomcat-embed-core-9.0.17.jar:9.0.17]
    at java.lang.Thread.run(Thread.java:748) [na:1.8.0_202]
spring-mvc

4条答案

按热度按时间
6za6bjd0

6za6bjd01#

有两种方法可以处理这种情况。
解决方案1.
在惰性对象顶部添加下方注解。

@JsonIgnoreProperties({"hibernateLazyInitializer", "handler"})

解决方案2.
正在www.example.com文件中添加以下属性application.properties。

spring.jackson.serialization.fail-on-empty-beans=false

注意：解决方案2仅隐藏错误。

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ws51t4hk

ws51t4hk2#

另一个解决方案是定制您自己的JSON序列化以处理Hibernate对象。这比日志中给出的替代方案要好得多，因为添加spring.jackson.serialization.fail_on_empty_beans=false将返回相关对象，即使不需要它，因此它使延迟检索完全无用。
Jackson的Hibernate模块的依赖关系：

<dependency>
    <groupId>com.fasterxml.jackson.datatype</groupId>
    <artifactId>jackson-datatype-hibernate5</artifactId>
</dependency>

解决方法：

@Configuration
public class JsonConfiguration {

    @Bean
    public Module hibernateModule() {
        return new Hibernate5Module();
    }
}
赞(0）分享  回复(0）举报  2022-11-15
gj3fmq9x

gj3fmq9x3#

在pom.xml中添加以下内容，对我很有用。

<dependency>
        <groupId>org.apache.tomcat</groupId>
        <artifactId>tomcat-jasper</artifactId>
        <version>9.0.65</version>
</dependency>
赞(0）分享  回复(0）举报  2022-11-15
2w3rbyxf

2w3rbyxf4#

尝试用途：

return userRepository.findById(userId).get();

取而代之

return userRepository.getById(userId);
赞(0）分享  回复(0）举报  2022-11-15
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