spring @SessionAttributes和“在提交响应后无法创建会话”

Question

我正在尝试设置并获取会话属性，但是我误解了它的工作方式或做错了什么。

请有人解释为什么这行不通。

我有以下简单的Spring Web MVC Controller

@Controller
@SessionAttributes("sessid")
@RequestMapping("sesstest")
public class SessTest 
{
    @RequestMapping("in")
    @ResponseBody
    public String in(ModelMap model){
        String uuid = UUID.randomUUID().toString();
        model.addAttribute("sessid", uuid);
        return uuid;
    }

    @RequestMapping("out")
    @ResponseBody
    public String out(@ModelAttribute("sessid") String sesid){
        return sesid;
    }
}

此类应仅在调用/ sesstest / in时设置会话变量，然后在调用/ sesstest / out时调用它

但是在调用/ in时得到以下异常

（堆栈跟踪显示在控制台上，Web输出正常。）

java.lang.IllegalStateException: Cannot create a session after the response has been committed
    at org.apache.catalina.connector.Request.doGetSession(Request.java:2872)
    at org.apache.catalina.connector.Request.getSession(Request.java:2249)
    at org.apache.catalina.connector.RequestFacade.getSession(RequestFacade.java:895)
    at org.springframework.web.context.request.ServletRequestAttributes.getSession(ServletRequestAttributes.java:111)
    at org.springframework.web.context.request.ServletRequestAttributes.setAttribute(ServletRequestAttributes.java:161)
    at org.springframework.web.bind.support.DefaultSessionAttributeStore.storeAttribute(DefaultSessionAttributeStore.java:55)
    at org.springframework.web.method.annotation.SessionAttributesHandler.storeAttributes(SessionAttributesHandler.java:124)
    at org.springframework.web.method.annotation.ModelFactory.updateModel(ModelFactory.java:232)
    at org.springframework.web.servlet.mvc.method.annotation.RequestMappingHandlerAdapter.getModelAndView(RequestMappingHandlerAdapter.java:879)
    at org.springframework.web.servlet.mvc.method.annotation.RequestMappingHandlerAdapter.invokeHandleMethod(RequestMappingHandlerAdapter.java:782)
    at org.springframework.web.servlet.mvc.method.annotation.RequestMappingHandlerAdapter.handleInternal(RequestMappingHandlerAdapter.java:705)
    at org.springframework.web.servlet.mvc.method.AbstractHandlerMethodAdapter.handle(AbstractHandlerMethodAdapter.java:85)
    at org.springframework.web.servlet.DispatcherServlet.doDispatch(DispatcherServlet.java:959)
    at org.springframework.web.servlet.DispatcherServlet.doService(DispatcherServlet.java:893)
    at org.springframework.web.servlet.FrameworkServlet.processRequest(FrameworkServlet.java:966)
    at org.springframework.web.servlet.FrameworkServlet.doGet(FrameworkServlet.java:857)
    at javax.servlet.http.HttpServlet.service(HttpServlet.java:618)
    at org.springframework.web.servlet.FrameworkServlet.service(FrameworkServlet.java:842)
    at javax.servlet.http.HttpServlet.service(HttpServlet.java:725)
    at org.apache.catalina.core.ApplicationFilterChain.internalDoFilter(ApplicationFilterChain.java:291)
    at org.apache.catalina.core.ApplicationFilterChain.doFilter(ApplicationFilterChain.java:206)
    at org.apache.tomcat.websocket.server.WsFilter.doFilter(WsFilter.java:52)
    at org.apache.catalina.core.ApplicationFilterChain.internalDoFilter(ApplicationFilterChain.java:239)
    at org.apache.catalina.core.ApplicationFilterChain.doFilter(ApplicationFilterChain.java:206)
    at org.springframework.web.filter.HiddenHttpMethodFilter.doFilterInternal(HiddenHttpMethodFilter.java:77)
    at org.springframework.web.filter.OncePerRequestFilter.doFilter(OncePerRequestFilter.java:107)
    at org.apache.catalina.core.ApplicationFilterChain.internalDoFilter(ApplicationFilterChain.java:239)
    at org.apache.catalina.core.ApplicationFilterChain.doFilter(ApplicationFilterChain.java:206)
    at org.springframework.web.filter.CharacterEncodingFilter.doFilterInternal(CharacterEncodingFilter.java:85)
    at org.springframework.web.filter.OncePerRequestFilter.doFilter(OncePerRequestFilter.java:107)
    at org.apache.catalina.core.ApplicationFilterChain.internalDoFilter(ApplicationFilterChain.java:239)
    at org.apache.catalina.core.ApplicationFilterChain.doFilter(ApplicationFilterChain.java:206)
    at org.apache.catalina.core.StandardWrapperValve.invoke(StandardWrapperValve.java:219)
    at org.apache.catalina.core.StandardContextValve.invoke(StandardContextValve.java:106)
    at org.apache.catalina.authenticator.AuthenticatorBase.invoke(AuthenticatorBase.java:501)
    at org.apache.catalina.core.StandardHostValve.invoke(StandardHostValve.java:142)
    at org.apache.catalina.valves.ErrorReportValve.invoke(ErrorReportValve.java:79)
    at org.apache.catalina.core.StandardEngineValve.invoke(StandardEngineValve.java:88)
    at org.apache.catalina.connector.CoyoteAdapter.service(CoyoteAdapter.java:516)
    at org.apache.coyote.http11.AbstractHttp11Processor.process(AbstractHttp11Processor.java:1086)
    at org.apache.coyote.AbstractProtocol$AbstractConnectionHandler.process(AbstractProtocol.java:659)
    at org.apache.coyote.http11.Http11NioProtocol$Http11ConnectionHandler.process(Http11NioProtocol.java:223)
    at org.apache.tomcat.util.net.NioEndpoint$SocketProcessor.doRun(NioEndpoint.java:1558)
    at org.apache.tomcat.util.net.NioEndpoint$SocketProcessor.run(NioEndpoint.java:1515)
    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)

谢谢！

Answer 1

正式地，这种“按设计工作”。

在这种情况下，各种解决方法是：

1. 手动开始会议
2. 使用过滤器以确保存在会话
3. 使用模型中的视图渲染。

请在此处查看Rossen的明确答复：https : //jira.spring.io/browse/SPR-12877

该场景有些不寻常，因为通常将模型属性用于视图渲染（例如HTML模板）。对于@ResponseBody，仅返回值用于呈现响应。也就是说，使用@ResponseBody并不排除使用@SessionAttributes。该错误与尝试第一次创建会话太晚有关。通常，使用带有过滤器的Spring Security之类的东西在会话中存储身份验证可以确保始终存在HTTP会话。如果没有，您可以添加自己的Filter或HandlerInterceptor，它们仅调用request.getSession（true）。这足以确保存在会话。

不能与之争论。