Question

我试图在Java Web应用程序中实现长轮询。该应用程序是使用Spring MVC 3.2编写的，我使用了DeferredResult对象（它代表了Servlet 3.0异步响应功能）。

问题是当使用DeferredResult时，每次发送请求10秒后我都会收到内部服务器错误（代码500）。预期结果是30秒后的文本数据。我的应用程序日志中没有任何内容，Tomcat日志中没有任何内容，但在FireFox网络监视器中，我看到此错误。

另一方面，当我发送同步请求并在服务器中保持30秒时，它成功完成。

任何人都可以帮我吗？

本文末尾有一个测试应用程序下载链接。这是一个maven应用程序。

这是我的应用代码：

ResponseController.java

@Controller
@RequestMapping("responses")
public class ResponseController {

    @Autowired
    private ResponseService messagesService;

    @RequestMapping(value="/async", method=RequestMethod.GET)
    @ResponseBody
    public DeferredResult<String> getAsyncUpdate() {
        return messagesService.getAsyncUpdate();
    }

    @RequestMapping(value="/sync", method=RequestMethod.GET)
    @ResponseBody
    public String getSyncUpdate() {
        return messagesService.getSyncUpdate();
    }

}

ResponseService.java

@Service
public class ResponseService {

    private DeferredResult<String> deferredResult;

    public DeferredResult<String> getAsyncUpdate(){
        deferredResult = new DeferredResult<String>();
        return deferredResult;
    }

    public String getSyncUpdate(){
        long startTime = System.currentTimeMillis();
        while( System.currentTimeMillis() - startTime <30000){

        }
        return "RESULT";
    }

    @Scheduled(fixedDelay=500)
    public void refresh(){
        if(deferredResult != null){
            long startTime = System.currentTimeMillis();
            while( System.currentTimeMillis() - startTime <30000){

            }
            deferredResult.setResult("RESULT");
        }
    }

}

MVC-调度-servlet.xml中

<?xml version="1.0" encoding="UTF-8"?>
<beans xmlns="http://www.springframework.org/schema/beans"
    xmlns:jee="http://www.springframework.org/schema/jee"
    xmlns:context="http://www.springframework.org/schema/context"
    xmlns:mvc="http://www.springframework.org/schema/mvc"
    xmlns:aop="http://www.springframework.org/schema/aop"
    xmlns:tx="http://www.springframework.org/schema/tx"
    xmlns:task="http://www.springframework.org/schema/task"
    xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
    xsi:schemaLocation="
        http://www.springframework.org/schema/beans     
        http://www.springframework.org/schema/beans/spring-beans-3.2.xsd
        http://www.springframework.org/schema/mvc     
        http://www.springframework.org/schema/mvc/spring-mvc-3.2.xsd
        http://www.springframework.org/schema/context 
        http://www.springframework.org/schema/context/spring-context-3.2.xsd
        http://www.springframework.org/schema/tx
        http://www.springframework.org/schema/tx/spring-tx.xsd
        http://www.springframework.org/schema/aop
        http://www.springframework.org/schema/aop/spring-aop.xsd
        http://www.springframework.org/schema/jee
        http://www.springframework.org/schema/jee/spring-jee-3.2.xsd
        http://www.springframework.org/schema/task 
        http://www.springframework.org/schema/task/spring-task-3.0.xsd">

    <context:component-scan base-package="pl.prv.mra.test.app" />
    <context:annotation-config/>

    <aop:aspectj-autoproxy/>

    <mvc:annotation-driven >
        <mvc:message-converters>
            <bean class="org.springframework.http.converter.json.MappingJacksonHttpMessageConverter" />
        </mvc:message-converters>
    </mvc:annotation-driven>

    <task:annotation-driven/>

    <mvc:resources location="/resources/**" mapping="/resources/**"/>

    <bean class="org.springframework.web.servlet.view.InternalResourceViewResolver">
        <property name="prefix" value="/WEB-INF/pages/"/>
        <property name="suffix" value=".jsp"/>
    </bean>

</beans>

异步响应的JQuery请求

$.ajax({
    url : "responses/async",
    type : "GET",
    timeout : 60000,
    dataType : "json",
    success : function(){
        alert('SUCCESS');
    },
    error : function(){
        alert('FAILURE');
    }
});

JQuery请求同步响应

$.ajax({
    url : "responses/sync",
    type : "GET",
    timeout : 60000,
    dataType : "json",
    success : function(){
        alert('SUCCESS');
    },
    error : function(){
        alert('FAILURE');
    }
});

的web.xml

<?xml version="1.0" encoding="UTF-8"?>
<web-app xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
    xmlns="http://java.sun.com/xml/ns/javaee"
    xsi:schemaLocation="http://java.sun.com/xml/ns/javaee http://java.sun.com/xml/ns/javaee/web-app_3_0.xsd"
    version="3.0">

    <display-name>test-app</display-name>

    <servlet>
        <servlet-name>mvc-dispatcher</servlet-name>
        <servlet-class>org.springframework.web.servlet.DispatcherServlet</servlet-class>
        <async-supported>true</async-supported>
    </servlet>

    <servlet-mapping>
        <servlet-name>mvc-dispatcher</servlet-name>
        <url-pattern>/</url-pattern>
    </servlet-mapping>

    <context-param>
        <param-name>contextConfigLocation</param-name>
        <param-value>/WEB-INF/mvc-dispatcher-servlet.xml</param-value>
    </context-param>

    <listener>
        <listener-class>org.springframework.web.context.ContextLoaderListener</listener-class>
    </listener>

</web-app>

Tomcat server.xml文件

<?xml version='1.0' encoding='utf-8'?>
<Server port="8005" shutdown="SHUTDOWN">
    <Listener className="org.apache.catalina.core.AprLifecycleListener"
        SSLEngine="on" />
    <Listener className="org.apache.catalina.core.JasperListener" />
    <Listener className="org.apache.catalina.core.JreMemoryLeakPreventionListener" />
    <Listener className="org.apache.catalina.mbeans.GlobalResourcesLifecycleListener" />
    <Listener className="org.apache.catalina.core.ThreadLocalLeakPreventionListener" />

    <GlobalNamingResources>
        <Resource name="UserDatabase" auth="Container"
            type="org.apache.catalina.UserDatabase" description="User database that can be updated and saved"
            factory="org.apache.catalina.users.MemoryUserDatabaseFactory"
            pathname="conf/tomcat-users.xml" />
    </GlobalNamingResources>

    <Service name="Catalina">

        <Connector port="8080" protocol="HTTP/1.1"
            connectionTimeout="20000" redirectPort="8443" />

        <Connector port="8009" protocol="AJP/1.3" redirectPort="8443" />

        <Engine name="Catalina" defaultHost="localhost">

            <Realm className="org.apache.catalina.realm.LockOutRealm">
                <Realm className="org.apache.catalina.realm.UserDatabaseRealm"
                    resourceName="UserDatabase" />
            </Realm>

            <Host name="localhost" appBase="webapps" unpackWARs="true"
                autoDeploy="true">

                <Valve className="org.apache.catalina.valves.AccessLogValve"
                    directory="logs" prefix="localhost_access_log." suffix=".txt"
                    pattern="%h %l %u %t &quot;%r&quot; %s %b" />

            </Host>
        </Engine>
    </Service>
</Server>

我的环境配置

操作系统：Linux Mint 16
服务器：Apache Tomcat 7.0.55
Java：Java 1.7.0_67

Test application download link

更新1

以下是回复数据：

回复标题：

连接：＆＃34;关闭＆＃34;

内容长度：＆＃34; 0＆＃34;

日期：＆＃34;星期一，2014年10月27日19:48:10 GMT＆＃34;

服务器：＆＃34; Apache-Coyote / 1.1＆＃34;

更新2

这是我的应用程序日志。我已将日志记录级别配置为ALL。不幸的是，根本没有任何错误。（我对tomcat日志做了同样的结果）：

2014-11-01 15:33:09 DEBUG RequestMappingHandlerMapping:220 - Looking up handler method for path /responses/async
2014-11-01 15:33:09 TRACE RequestMappingHandlerMapping:264 - Found 1 matching mapping(s) for [/responses/async] : [{[/responses/async],methods=[GET],params=[],headers=[],consumes=[],produces=[],custom=[]}]
2014-11-01 15:33:09 DEBUG RequestMappingHandlerMapping:227 - Returning handler method [public org.springframework.web.context.request.async.DeferredResult<java.lang.String> pl.prv.mra.test.app.controllers.ResponseController.getAsyncUpdate()]
2014-11-01 15:33:09 DEBUG DefaultListableBeanFactory:246 - Returning cached instance of singleton bean 'responseController'
2014-11-01 15:33:09 TRACE DispatcherServlet:1122 - Testing handler adapter [org.springframework.web.servlet.mvc.method.annotation.RequestMappingHandlerAdapter@7e036b3]
2014-11-01 15:33:09 DEBUG DispatcherServlet:912 - Last-Modified value for [/test-app/responses/async] is: -1
2014-11-01 15:33:09 TRACE HandlerMethod:129 - Invoking [getAsyncUpdate] method with arguments []
2014-11-01 15:33:09 TRACE HandlerMethod:135 - Method [getAsyncUpdate] returned [org.springframework.web.context.request.async.DeferredResult@4810881c]
2014-11-01 15:33:09 TRACE HandlerMethodReturnValueHandlerComposite:78 - Testing if return value handler [org.springframework.web.servlet.mvc.method.annotation.ModelAndViewMethodReturnValueHandler@2a426218] supports [org.springframework.web.context.request.async.DeferredResult<java.lang.String>]
2014-11-01 15:33:09 TRACE HandlerMethodReturnValueHandlerComposite:78 - Testing if return value handler [org.springframework.web.method.annotation.ModelMethodProcessor@6c362b54] supports [org.springframework.web.context.request.async.DeferredResult<java.lang.String>]
2014-11-01 15:33:09 TRACE HandlerMethodReturnValueHandlerComposite:78 - Testing if return value handler [org.springframework.web.servlet.mvc.method.annotation.ViewMethodReturnValueHandler@5856cf4c] supports [org.springframework.web.context.request.async.DeferredResult<java.lang.String>]
2014-11-01 15:33:09 TRACE HandlerMethodReturnValueHandlerComposite:78 - Testing if return value handler [org.springframework.web.servlet.mvc.method.annotation.HttpEntityMethodProcessor@2b43b3e3] supports [org.springframework.web.context.request.async.DeferredResult<java.lang.String>]
2014-11-01 15:33:09 TRACE HandlerMethodReturnValueHandlerComposite:78 - Testing if return value handler [org.springframework.web.servlet.mvc.method.annotation.CallableMethodReturnValueHandler@deae877] supports [org.springframework.web.context.request.async.DeferredResult<java.lang.String>]
2014-11-01 15:33:09 TRACE HandlerMethodReturnValueHandlerComposite:78 - Testing if return value handler [org.springframework.web.servlet.mvc.method.annotation.DeferredResultMethodReturnValueHandler@3943e3c4] supports [org.springframework.web.context.request.async.DeferredResult<java.lang.String>]
2014-11-01 15:33:10 DEBUG WebAsyncManager:429 - Concurrent handling starting for GET [/test-app/responses/async]
2014-11-01 15:33:10 TRACE DispatcherServlet:1028 - Cleared thread-bound request context: org.apache.catalina.connector.RequestFacade@655d2842
2014-11-01 15:33:10 DEBUG DispatcherServlet:963 - Leaving response open for concurrent processing
2014-11-01 15:33:10 TRACE XmlWebApplicationContext:332 - Publishing event in WebApplicationContext for namespace 'mvc-dispatcher-servlet': ServletRequestHandledEvent: url=[/test-app/responses/async]; client=[127.0.0.1]; method=[GET]; servlet=[mvc-dispatcher]; session=[55143812B6586F66C0001D3F41B1947C]; user=[null]; time=[13ms]; status=[OK]
2014-11-01 15:33:10 TRACE XmlWebApplicationContext:332 - Publishing event in Root WebApplicationContext: ServletRequestHandledEvent: url=[/test-app/responses/async]; client=[127.0.0.1]; method=[GET]; servlet=[mvc-dispatcher]; session=[55143812B6586F66C0001D3F41B1947C]; user=[null]; time=[13ms]; status=[OK]

Answer 1

确定。我找到了解决方案。

在Tomcat配置中（在server.xml文件中）有一个HTTP / 1.1连接器。我认为connectionTimeout参数定义了每个连接的超时，但它没有。

对于异步连接（在我的例子中），有一个名为asyncTimeout的独立参数。它的默认值是10秒。

像这样设置：

<Connector port="8080" protocol="HTTP/1.1" asyncTimeout="60000" connectionTimeout="20000" redirectPort="8443" />

解决了我的问题。

Answer 2

我遇到了同样的问题，而asyncTimeout还不够... 我当时使用Zuul来反向代理我的api，却忘记添加zuul.host.connect-timeout-millis和zuul.host.socket-timeout-millis，您的解决方案+这个解决了我的问题。

长轮询时，10秒后Tomcat 7服务器错误

2 个答案: