已经为此响应调用了 Spring boot getOutputStream()

Question

我已经浏览了 SO 上的各种链接，但没有一个对我有用。

这是我在尝试使用 Rest Controller 获取数据时遇到的异常

java.lang.IllegalStateException: getOutputStream() has already been called for this response
at org.apache.catalina.connector.Response.getWriter(Response.java:678) ~[catalina.jar:7.0.57]
at org.apache.catalina.connector.ResponseFacade.getWriter(ResponseFacade.java:213) ~[catalina.jar:7.0.57]
at org.springframework.boot.autoconfigure.web.ErrorMvcAutoConfiguration$SpelView.render(ErrorMvcAutoConfiguration.java:227) ~[spring-boot-autoconfigure-1.5.1.RELEASE.jar:1.5.1.RELEASE]
at org.springframework.web.servlet.DispatcherServlet.render(DispatcherServlet.java:1271) ~[spring-webmvc-4.3.6.RELEASE.jar:4.3.6.RELEASE]
at org.springframework.web.servlet.DispatcherServlet.processDispatchResult(DispatcherServlet.java:1037) ~[spring-webmvc-4.3.6.RELEASE.jar:4.3.6.RELEASE]
at org.springframework.web.servlet.DispatcherServlet.doDispatch(DispatcherServlet.java:980) ~[spring-webmvc-4.3.6.RELEASE.jar:4.3.6.RELEASE]
at org.springframework.web.servlet.DispatcherServlet.doService(DispatcherServlet.java:897) ~[spring-webmvc-4.3.6.RELEASE.jar:4.3.6.RELEASE]
at org.springframework.web.servlet.FrameworkServlet.processRequest(FrameworkServlet.java:970) ~[spring-webmvc-4.3.6.RELEASE.jar:4.3.6.RELEASE]
at org.springframework.web.servlet.FrameworkServlet.doGet(FrameworkServlet.java:861) ~[spring-webmvc-4.3.6.RELEASE.jar:4.3.6.RELEASE]
at javax.servlet.http.HttpServlet.service(HttpServlet.java:620) ~[servlet-api.jar:na]
at org.springframework.web.servlet.FrameworkServlet.service(FrameworkServlet.java:846) ~[spring-webmvc-4.3.6.RELEASE.jar:4.3.6.RELEASE]
at javax.servlet.http.HttpServlet.service(HttpServlet.java:727) ~[servlet-api.jar:na]
at org.apache.catalina.core.ApplicationFilterChain.internalDoFilter(ApplicationFilterChain.java:303) [catalina.jar:7.0.57]
at org.apache.catalina.core.ApplicationFilterChain.doFilter(ApplicationFilterChain.java:208) [catalina.jar:7.0.57]
at org.apache.tomcat.websocket.server.WsFilter.doFilter(WsFilter.java:52) ~[tomcat7-websocket.jar:7.0.57]
at org.apache.catalina.core.ApplicationFilterChain.internalDoFilter(ApplicationFilterChain.java:241) [catalina.jar:7.0.57]
at org.apache.catalina.core.ApplicationFilterChain.doFilter(ApplicationFilterChain.java:208) [catalina.jar:7.0.57]
at org.springframework.web.filter.RequestContextFilter.doFilterInternal(RequestContextFilter.java:99) ~[spring-web-4.3.6.RELEASE.jar:4.3.6.RELEASE]
at org.springframework.web.filter.OncePerRequestFilter.doFilter(OncePerRequestFilter.java:107) [spring-web-4.3.6.RELEASE.jar:4.3.6.RELEASE]
at org.apache.catalina.core.ApplicationFilterChain.internalDoFilter(ApplicationFilterChain.java:241) [catalina.jar:7.0.57]
at org.apache.catalina.core.ApplicationFilterChain.doFilter(ApplicationFilterChain.java:208) [catalina.jar:7.0.57]
at org.springframework.web.filter.OncePerRequestFilter.doFilter(OncePerRequestFilter.java:101) [spring-web-4.3.6.RELEASE.jar:4.3.6.RELEASE]
at org.apache.catalina.core.ApplicationFilterChain.internalDoFilter(ApplicationFilterChain.java:241) [catalina.jar:7.0.57]
at org.apache.catalina.core.ApplicationFilterChain.doFilter(ApplicationFilterChain.java:208) [catalina.jar:7.0.57]
at org.springframework.web.filter.OncePerRequestFilter.doFilter(OncePerRequestFilter.java:101) [spring-web-4.3.6.RELEASE.jar:4.3.6.RELEASE]
at org.apache.catalina.core.ApplicationFilterChain.internalDoFilter(ApplicationFilterChain.java:241) [catalina.jar:7.0.57]
at org.apache.catalina.core.ApplicationFilterChain.doFilter(ApplicationFilterChain.java:208) [catalina.jar:7.0.57]
at org.springframework.web.filter.OncePerRequestFilter.doFilter(OncePerRequestFilter.java:101) [spring-web-4.3.6.RELEASE.jar:4.3.6.RELEASE]
at org.apache.catalina.core.ApplicationFilterChain.internalDoFilter(ApplicationFilterChain.java:241) [catalina.jar:7.0.57]
at org.apache.catalina.core.ApplicationFilterChain.doFilter(ApplicationFilterChain.java:208) [catalina.jar:7.0.57]
at org.springframework.web.filter.OncePerRequestFilter.doFilter(OncePerRequestFilter.java:101) [spring-web-4.3.6.RELEASE.jar:4.3.6.RELEASE]
at org.springframework.boot.web.support.ErrorPageFilter.doFilter(ErrorPageFilter.java:108) [spring-boot-1.5.1.RELEASE.jar:1.5.1.RELEASE]
at org.apache.catalina.core.ApplicationFilterChain.internalDoFilter(ApplicationFilterChain.java:241) [catalina.jar:7.0.57]
at org.apache.catalina.core.ApplicationFilterChain.doFilter(ApplicationFilterChain.java:208) [catalina.jar:7.0.57]
at org.apache.catalina.core.ApplicationDispatcher.invoke(ApplicationDispatcher.java:748) ~[catalina.jar:7.0.57]
at org.apache.catalina.core.ApplicationDispatcher.processRequest(ApplicationDispatcher.java:486) ~[catalina.jar:7.0.57]
at org.apache.catalina.core.ApplicationDispatcher.doForward(ApplicationDispatcher.java:411) ~[catalina.jar:7.0.57]
at org.apache.catalina.core.ApplicationDispatcher.forward(ApplicationDispatcher.java:338) ~[catalina.jar:7.0.57]
at org.springframework.boot.web.support.ErrorPageFilter.handleErrorStatus(ErrorPageFilter.java:149) [spring-boot-1.5.1.RELEASE.jar:1.5.1.RELEASE]
at org.springframework.boot.web.support.ErrorPageFilter.doFilter(ErrorPageFilter.java:117) [spring-boot-1.5.1.RELEASE.jar:1.5.1.RELEASE]
at org.springframework.boot.web.support.ErrorPageFilter.access$000(ErrorPageFilter.java:59) [spring-boot-1.5.1.RELEASE.jar:1.5.1.RELEASE]
at org.springframework.boot.web.support.ErrorPageFilter$1.doFilterInternal(ErrorPageFilter.java:90) [spring-boot-1.5.1.RELEASE.jar:1.5.1.RELEASE]
at org.springframework.web.filter.OncePerRequestFilter.doFilter(OncePerRequestFilter.java:107) [spring-web-4.3.6.RELEASE.jar:4.3.6.RELEASE]
at org.springframework.boot.web.support.ErrorPageFilter.doFilter(ErrorPageFilter.java:108) [spring-boot-1.5.1.RELEASE.jar:1.5.1.RELEASE]
at org.apache.catalina.core.ApplicationFilterChain.internalDoFilter(ApplicationFilterChain.java:241) [catalina.jar:7.0.57]
at org.apache.catalina.core.ApplicationFilterChain.doFilter(ApplicationFilterChain.java:208) [catalina.jar:7.0.57]
at org.apache.catalina.core.StandardWrapperValve.invoke(StandardWrapperValve.java:220) [catalina.jar:7.0.57]
at org.apache.catalina.core.StandardContextValve.invoke(StandardContextValve.java:122) [catalina.jar:7.0.57]
at org.apache.catalina.authenticator.AuthenticatorBase.invoke(AuthenticatorBase.java:503) [catalina.jar:7.0.57]
at org.apache.catalina.core.StandardHostValve.invoke(StandardHostValve.java:170) [catalina.jar:7.0.57]
at org.apache.catalina.valves.ErrorReportValve.invoke(ErrorReportValve.java:103) [catalina.jar:7.0.57]
at org.apache.catalina.valves.AccessLogValve.invoke(AccessLogValve.java:950) [catalina.jar:7.0.57]
at org.apache.catalina.core.StandardEngineValve.invoke(StandardEngineValve.java:116) [catalina.jar:7.0.57]
at org.apache.catalina.connector.CoyoteAdapter.service(CoyoteAdapter.java:421) [catalina.jar:7.0.57]
at org.apache.coyote.http11.AbstractHttp11Processor.process(AbstractHttp11Processor.java:1070) [tomcat-coyote.jar:7.0.57]
at org.apache.coyote.AbstractProtocol$AbstractConnectionHandler.process(AbstractProtocol.java:611) [tomcat-coyote.jar:7.0.57]
at org.apache.tomcat.util.net.JIoEndpoint$SocketProcessor.run(JIoEndpoint.java:314) [tomcat-coyote.jar:7.0.57]
at java.util.concurrent.ThreadPoolExecutor.runWorker(Unknown Source) [na:1.8.0_20]
at java.util.concurrent.ThreadPoolExecutor$Worker.run(Unknown Source) [na:1.8.0_20]
at org.apache.tomcat.util.threads.TaskThread$WrappingRunnable.run(TaskThread.java:61) [tomcat-coyote.jar:7.0.57]
at java.lang.Thread.run(Unknown Source) [na:1.8.0_20]

我有两个使用@ManyToOne 映射映射的实体类。

@Entity
@Table(name = "products")
public class ProductInfo {
@ManyToOne(fetch = FetchType.LAZY, cascade= CascadeType.ALL)
    @JoinColumn(name = "names")
    private ProductDetails names;
}
//Getter setter



@Entity
@Table(name = "product_details")
public class ProductDetails {
@Id
    private String name;
}
//Getter Setter

这是控制器代码

@RequestMapping(value = "/getProducts", method = RequestMethod.GET, produces = "application/json")
public ResponseEntity<Iterable<ProductInfo>> getProductInfo() {
    Iterable<ProductInfo> products = repo.findAll();
    logger.debug("Found Products ::" + products );
    return new ResponseEntity<Iterable<ProductInfo>>(products, HttpStatus.OK);
}

在没有映射的情况下，我能够获得产品信息。当我添加映射时，我得到了 LazyInitialization 异常。我在application.properties 文件中添加了spring.jpa.properties.hibernate.enable_lazy_load_no_trans=true。现在我得到了上述异常。

非常感谢任何帮助！

Answer 1

遇到了同样的问题，我将 fetch 类型的形式从惰性更改为渴望，它解决了我的问题，正如 PRATHAP 评论的那样