AsyncServlet

import java.io.IOException;
import java.util.concurrent.CompletableFuture;
import java.util.concurrent.TimeUnit;
import javax.servlet.AsyncContext;
import javax.servlet.ServletException;
import javax.servlet.ServletRequest;
import javax.servlet.ServletResponse;
import javax.servlet.annotation.WebServlet;
import javax.servlet.http.HttpServlet;
import javax.servlet.http.HttpServletRequest;
import javax.servlet.http.HttpServletResponse;
/**
 * Servlet implementation class AsyncServlet
 */
@WebServlet(asyncSupported = true, urlPatterns = { "/AsyncServlet" })
public class AsyncServlet extends HttpServlet {
    private static final long serialVersionUID = 1L;
    /**
     * @see HttpServlet#HttpServlet()
     */
    public AsyncServlet() {
        super();
        // TODO Auto-generated constructor stub
    }
    /**
     * @see HttpServlet#doGet(HttpServletRequest request, HttpServletResponse
     *      response)
     */
    protected void doGet(HttpServletRequest request,
            HttpServletResponse response) throws ServletException, IOException {
        long t1 = System.currentTimeMillis();
        // 开启异步
        AsyncContext asyncContext = request.startAsync();
        // 执行业务代码
        CompletableFuture.runAsync(() -> doSomeThing(asyncContext,
                asyncContext.getRequest(), asyncContext.getResponse()));
        System.out.println("async use:" + (System.currentTimeMillis() - t1));
    }
    private void doSomeThing(AsyncContext asyncContext,
            ServletRequest servletRequest, ServletResponse servletResponse) {
        // 模拟耗时操作
        try {
            TimeUnit.SECONDS.sleep(5);
        } catch (InterruptedException e) {
        }
        //
        try {
            servletResponse.getWriter().append("done");
        } catch (IOException e) {
            e.printStackTrace();
        }
        // 业务代码处理完毕, 通知结束
        asyncContext.complete();
    }
    /**
     * @see HttpServlet#doPost(HttpServletRequest request, HttpServletResponse
     *      response)
     */
    protected void doPost(HttpServletRequest request,
            HttpServletResponse response) throws ServletException, IOException {
        // TODO Auto-generated method stub
        doGet(request, response);
    }
}