Springmvc异步支持报错-

参看网上的springmvc异步支持的小例子，自己试了一下，使用ajax的请求处理方法如下：

@RequestMapping("/response-body")
	public @ResponseBody Callable<String> responseBody(){
		return new Callable<String>() {
			@Override
			public String call() throws Exception {
				Thread.sleep(2000);
				return "Callable result";
			}
		};
	}

但是在调用时出错：

Servlet.service() for servlet [springmvc] in context with path [/SpringMVC_Demo] threw exception [Request processing failed; nested exception is java.lang.IllegalStateException: Async support must be enabled on a servlet and for all filters involved in async request processing. This is done in Java code using the Servlet API or by adding "<async-supported>true</async-supported>" to servlet and filter declarations in web.xml.] with root cause
java.lang.IllegalStateException: Async support must be enabled on a servlet and for all filters involved in async request processing. This is done in Java code using the Servlet API or by adding "<async-supported>true</async-supported>" to servlet and filter declarations in web.xml.

但是自己也确实在web.xml中加入了异步支持

  <servlet>
    <servlet-name>springmvc</servlet-name>
    <servlet-class>org.springframework.web.servlet.DispatcherServlet</servlet-class>
    <init-param>
      <param-name>contextConfigLocation</param-name>
      <param-value>classpath:springmvc-servlet.xml</param-value>
    </init-param>
    <load-on-startup>1</load-on-startup>
    <!-- springmvc的异步支持 -->
    <async-supported>true</async-supported>
  </servlet>

仔细一看，报错提示有“filter declarations“ ，难道filter也要修改一下？

我的项目是用的以前练习时的项目，其中使用了springmvc的encoding-filter，为了验证猜想，将filter暂时注释掉，结果没再出错，说明对filter的使用也要加以异步支持声明。

现在在servlet和filter中也加入异步支持，再次重启，访问，也不会报错了。

参考：http://www.blogjava.net/yongboy/archive/2011/01/15/346203.html

http://wiselyman.iteye.com/blog/2215852