package org.servlet.async;
import java.io.IOException;
import java.util.Date;
import javax.servlet.AsyncContext;
import javax.servlet.ServletException;
import javax.servlet.annotation.WebServlet;
import javax.servlet.http.HttpServlet;
import javax.servlet.http.HttpServletRequest;
import javax.servlet.http.HttpServletResponse;
/*
* Copyright [2015] [Jeff Lee]
*
* Licensed under the Apache License, Version 2.0 (the "License");
* you may not use this file except in compliance with the License.
* You may obtain a copy of the License at
*
* http://www.apache.org/licenses/LICENSE-2.0
*
* Unless required by applicable law or agreed to in writing, software
* distributed under the License is distributed on an "AS IS" BASIS,
* WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
* See the License for the specific language governing permissions and
* limitations under the License.
*/
/**
* @author Jeff Lee
* @since 2015-9-3 20:30:19
* Servlet 3.0提供的异步处理
* 通过AsyncContext类实现，该对象从请求Request的startAsync方法获取。
*/
@WebServlet(urlPatterns="/async",asyncSupported=true)// 开始异步调用
public class AsyncServlet extends HttpServlet {
private static final long serialVersionUID = -6795872120748178723L;
@Override
protected void doGet(HttpServletRequest req, HttpServletResponse resp)
throws ServletException,IOException {
resp.setContentType("text/html;charset=UTF-8");
Date startDate = new Date();
System.out.println("Servlet当前时间 --- " + startDate );
// 从请求中获取AsyncContext
AsyncContext asyncContext = req.startAsync();
// 设置异步调用的超时时长
asyncContext.setTimeout(30*1000);// 30秒
// 开始异步调用
asyncContext.start(new AsyncThread(asyncContext));
Date endDate = new Date();
System.out.println("Servlet结束时间 --- " + endDate);
// startDate和endDate时间差不多相等。
// 说明Servlet重新发起了一条线程去掉用耗时业务方法，避免了阻塞式调用
}
}
