java.util.concurrent包中的BlockingQueue接口通常用于一个线程生产对象,而另一个线程消费这些对象的场景。
一个线程将会持续生产新对象并将其插入队列中,知道队列达到所能容纳的临界点。也就是说,队列是有限的。如果该阻塞队列到达了其临界点,负责生产的线程将会发生阻塞,且一直处于阻塞状态中,直到负责消费的线程从队列中拿走一个对象。负责消费的线程会一直从阻塞队列中拿出对象。如果消费线程尝试从一个空队列中提取对象的话,这个线程将会处于阻塞状态中,知道一个生产线程把一个对象放进队列。
BlockQueue是一个接口,你需要使用它的实现之一来使用,具体的实现有:ArrayBlockingQueue,DelayQueue,LinkedBlockingQueue,PriorityBlockingQueue,SynchronousQueue
package com.scm.servlet;
import java.io.IOException;
import java.util.LinkedList;
import java.util.Queue;
import java.util.concurrent.BlockingQueue;
import javax.servlet.ServletException;
import javax.servlet.annotation.WebServlet;
import javax.servlet.http.HttpServlet;
import javax.servlet.http.HttpServletRequest;
import javax.servlet.http.HttpServletResponse;
/**
* Servlet implementation class PhoneServlet
*/
@WebServlet("/PhoneServlet")
public class PhoneServlet extends HttpServlet {
private static final long serialVersionUID = 1L;
/**
* @see HttpServlet#HttpServlet()
*/
public PhoneServlet() {
super();
// TODO Auto-generated constructor stub
}
/**
* @see HttpServlet#doGet(HttpServletRequest request, HttpServletResponse response)
*/
protected void doGet(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException {
String phone = request.getParameter("phone");
BlockingQueue<String> phones = (BlockingQueue<String>) request.getServletContext().getAttribute("phones");
try {
// 加入队列
phones.put(phone);
} catch (InterruptedException e) {
// TODO Auto-generated catch block
e.printStackTrace();
}
response.getWriter().write("ok");
}
/**
* @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);
}
}
package com.scm.filter;
import java.util.LinkedList;
import java.util.Queue;
import java.util.concurrent.BlockingQueue;
import java.util.concurrent.LinkedBlockingDeque;
import javax.servlet.ServletContextEvent;
import javax.servlet.ServletContextListener;
import javax.servlet.annotation.WebListener;
@WebListener
public class SendCodeListener implements ServletContextListener{
@Override
public void contextInitialized(ServletContextEvent sce) {
// Queue<String> phones = new LinkedList<String>();
// 换成阻塞队列
BlockingQueue<String> phones = new LinkedBlockingDeque<String>();
sce.getServletContext().setAttribute("phones", phones);
// 开启一个 线程
new Thread(){
@Override
public void run() {
while(true) {
String phone;
try {
phone = phones.take();// 阻塞式 取不到值 阻塞
System.out.println("队列取出"+phone);
if(phone != null) {
System.out.println(phone+"---->短信发送成功");
}
} catch (InterruptedException e) {
// TODO Auto-generated catch block
e.printStackTrace();
}
}
}
}.start();
}
}