springmvc 配置异步请求

最开始按照网上配置了一个servlet class 没有继承Filter .结果报错.网上有文章说是tomcat 启动加载的servlet-3.0- api 加载了 tomcat 安装目录下lib里边的自带的 servlet api 与 环境中api冲突 改成

javax.servlet
javax.servlet-api
3.0.1
provided  

问题是配置文件里配置就是这样的

严重: Exception starting filter AsyncFilter
java.lang.ClassCastException: com.AsynDemo.AsynServ cannot be cast to javax.servlet.Filter
这个错误其实是没有继承Filter,重写一个过滤导致的

环境:

pom.xml

javax.servlet
javax.servlet-api
3.0.1
provided

 

web.xml 配置

这个是把你重写的过滤类写入
  
   pageResponse     
   class>com.AsynDemo.AsynServletclass> 
    <async-supported>trueasync-supported>

  
    pageResponse
   
   /* 

applicationContext
org.springframework.web.servlet.DispatcherServlet

contextConfigLocation
classpath:spring-common.xml

1
true  //

@Controller
@RequestMapping("/asyncServlet")
public class AsynServlet implements Filter
{
@Override
public void init(FilterConfig filterConfig) throws ServletException {
// TODO Auto-generated method stub

}

@RequestMapping(value="/testAsyn")
@Override
public void doFilter(ServletRequest request, ServletResponse response,
FilterChain chain) throws IOException, ServletException {
//request.setAttribute("org.apache.catalina.ASYNC_SUPPORTED", true);
System.out.println("start");
PrintWriter out = response.getWriter();
AsyncContext asyncContext = request.startAsync();
asyncContext.setTimeout(5000);
asyncContext.addListener(new MyAsyncListener());
new Thread(new Work(asyncContext,request)).start();
out.print("异步执行中");

}
@Override
public void destroy() {
// TODO Auto-generated method stub

}

}

 

就这么样了 还会报错

A filter or servlet of the current chain does not support asynchronous opera

request.setAttribute("org.apache.catalina.ASYNC_SUPPORTED", true);

查了查资料,

所有的解决办法都在说可能是参数配置未配置正确，或者是需要在server.xml上配置。最后，在StackOverflow上找到了如下答案

request.setAttribute("org.apache.catalina.ASYNC_SUPPORTED", true);

尝试这个改了改,问题解决

总结一下,这种配置文件的方式 .坑不少,但最终解决了. 

还有一种写法有空再测试

https://blog.csdn.net/zxaini2010/article/details/50358763

转载于:https://www.cnblogs.com/zuochanzi/p/9611088.html