SpringMVC配置使用servlet3.0异步请求AsyncContext示例_SpringMVC_Servlet_异步_AsyncContext - 小郝不负流年

介绍

为了支持异步处理，在Servlet 3.0中，在ServletRequest上提供了startAsync()方法

配置

SpringMVC支持异步配置

springmvc-servlet.xml：
<mvc:annotation-driven>
<mvc:async-support default-timeout="5000"/>
mvc:annotation-driven>
web.xml的所有servlet和filter
<async-supported>trueasync-supported>

示例

@Controller
@RequestMapping("/test")
public class AsyncTestController extends BaseController {
@RequestMapping(value = "/async", method = RequestMethod.GET)
public void testAsync(HttpServletRequest request, HttpServletResponse response) throws IOException {
LOGGER.info("=== 开始");
PrintWriter out = response.getWriter();
AsyncContext asyncContext = request.startAsync();
asyncContext.setTimeout(5000L); // 设置0表示永不超时
asyncContext.addListener(new TestAsyncListener());
new Thread(new WorkThread(asyncContext)).start();
LOGGER.info("=== 异步进行中");
out.println("async exce...");
}
}
public class WorkThread implements Runnable {
private AsyncContext asyncContext;
public WorkThread(AsyncContext asyncContext) {
this.asyncContext = asyncContext;
}
@Override
public void run() {
try {
Thread.sleep(6000);
try {
ServletResponse response = asyncContext.getResponse();
PrintWriter out = response.getWriter();
out.println("work thread excute is finished!");
// out.close(); // 可以放到listener.onComplete里面关闭
} catch (IOException e) {
e.printStackTrace();
}
asyncContext.complete();
} catch (InterruptedException e) {
e.printStackTrace();
}
}
}
public class TestAsyncListener implements AsyncListener {
@Override
public void onComplete(AsyncEvent asyncEvent) throws IOException {
try {
AsyncContext asyncContext = asyncEvent.getAsyncContext();
ServletResponse response = asyncContext.getResponse();
ServletRequest request = asyncContext.getRequest();
PrintWriter out= response.getWriter();
if (request.getAttribute("timeout") != null &&
StringUtil.equals("true",request.getAttribute("timeout").toString())) {//超时
out.println("onComplete timeout ");
LOGGER.info("onComplete timeout");
}else {//未超时
out.println("OnComplete normal");
LOGGER.info("OnComplete normal");
}
out.close();
} catch (IOException e) {
e.printStackTrace();
}
}
@Override
public void onError(AsyncEvent asyncEvent) throws IOException {
LOGGER.info("=== onError");
}
@Override
public void onStartAsync(AsyncEvent arg0) throws IOException {
LOGGER.info("=== onStartAsync");
}
@Override
public void onTimeout(AsyncEvent asyncEvent) throws IOException {
ServletRequest request = asyncEvent.getAsyncContext().getRequest();
request.setAttribute("timeout", "true");
LOGGER.info("=== onTimeout");
}
}

总结

Listener.onComplete方法永远都会执行；

Listener.onTimeout方法在超时时才会执行。

其他的东西可以复制demo自己跑一下看一下就明白了。