Servlet 3使用Spring异步支持不起作用

Question

我正在尝试从服务器的文件系统中传输视频。我使用Spring的StreamingResponseBody作为响应返回。因此，我必须异步处理流。我做了很多关于如何配置我的web.xml和Spring的研究，我遵循了这个简单的教程：http://shengwangi.blogspot.de/2015/09/asynchronous-spring-mvc-hello-world.html，但不幸的是没有成功！我仍然得到异常，告诉我“必须在servlet上启用异步支持，对于异步请求处理中涉及的所有过滤器都启用异步支持。这是在Java代码中使用Servlet实现的，或者通过在servlet和filter声明中添加"true”来实现的，尽管我认为我做得很好。下面是我在web.xml中的servlet配置

<servlet>
        <servlet-name>dispatcherServlet</servlet-name>
        <servlet-class>org.springframework.web.servlet.DispatcherServlet</servlet-class>
        <init-param>
            <param-name>contextConfigLocation</param-name>
            <param-value>/WEB-INF/mvc-config.xml</param-value>
        </init-param>
        <load-on-startup>1</load-on-startup>
        <async-supported>true</async-supported>
    </servlet>

    <servlet-mapping>
        <servlet-name>dispatcherServlet</servlet-name>
        <url-pattern>/</url-pattern>
    </servlet-mapping>

    <listener>
        <listener-class>org.springframework.web.context.ContextLoaderListener</listener-class>
    </listener>
    <context-param>
        <param-name>contextConfigLocation</param-name>
        <param-value>/WEB-INF/application-context.xml</param-value>
    </context-param>
    <context-param>
        <param-name>spring.profiles.active</param-name>
        <param-value>production</param-value>
    </context-param>
    <filter>
        <filter-name>encodingFilter</filter-name>
        <filter-class>org.springframework.web.filter.CharacterEncodingFilter</filter-class>
        <init-param>
            <param-name>encoding</param-name>
            <param-value>UTF-8</param-value>
        </init-param>
        <init-param>
            <param-name>forceEncoding</param-name>
            <param-value>true</param-value>
        </init-param>
    </filter>
    <filter-mapping>
        <filter-name>encodingFilter</filter-name>
        <url-pattern>/*</url-pattern>
        <dispatcher>REQUEST</dispatcher>
        <dispatcher>ASYNC</dispatcher>
    </filter-mapping>
    <filter>
        <display-name>springSecurityFilterChain</display-name>
        <filter-name>springSecurityFilterChain</filter-name>
        <filter-class>org.springframework.web.filter.DelegatingFilterProxy</filter-class>
    </filter>
    <filter-mapping>
        <filter-name>springSecurityFilterChain</filter-name>
        <url-pattern>/*</url-pattern>
        <dispatcher>REQUEST</dispatcher>
        <dispatcher>ASYNC</dispatcher>
    </filter-mapping>

Spring配置的代码片段：

<mvc:annotation-driven>
    <mvc:async-support default-timeout="30000"  task-executor="taskExecutor">
    </mvc:async-support>
</mvc:annotation-driven>
<bean id="taskExecutor"
        class="org.springframework.scheduling.concurrent.ThreadPoolTaskExecutor">
    <property name="corePoolSize" value="5" />
    <property name="maxPoolSize" value="50" />
    <property name="queueCapacity" value="10" />
    <property name="keepAliveSeconds" value="120" />
</bean>

以下是请求处理程序：

@GetMapping("/videos/play")
    public StreamingResponseBody stream(@RequestParam("code") String code, @RequestParam("locale") String locale) throws FileNotFoundException{
        File video = videoService.getVideo(code, locale);
        final InputStream videoInputStream = new FileInputStream(video);
        return (outputStream) -> {
            copyToStream(videoInputStream, outputStream);
        };
    }
private void copyToStream(final InputStream is, OutputStream os)
            throws IOException {
        byte[] data = new byte[2048];
        int read = 0;
        while ((read = is.read(data)) > 0) {
            os.write(data, 0, read);
        }
        os.flush();
    }

我很感激任何帮助，因为我三天前还在挣扎！我使用Tomcat8.0和Spring4.3.6

Answer 1

我读过许多线程，表明它是Tomcat 7或8中的一个bug，但它并不是，异常清楚地表明，必须在所有过滤器中启用异步支持。由于我尝试这样做，但问题是如何在web.xml文件中的过滤器中添加异步支持。我所做的是

<filter-mapping>
        <filter-name>springSecurityFilterChain</filter-name>
        <url-pattern>/*</url-pattern>
        <dispatcher>REQUEST</dispatcher>
        <dispatcher>ASYNC</dispatcher>
</filter-mapping>

这实际上告诉我们，映射接受ASYNC请求(我猜)，但它不支持过滤器本身的异步支持。因此，在每个过滤器定义中，我们应该启用异步支持，因此springSecurityFilterChain定义变成：

<filter>
    <display-name>springSecurityFilterChain</display-name>
    <filter-name>springSecurityFilterChain</filter-name>
    <filter-class>org.springframework.web.filter.DelegatingFilterProxy</filter-class>
    <async-supported>true</async-supported>
</filter>