Java 线程池 发送邮件

想了解下Java线程池的用法，恰好最近要做一个简易的邮件通知中间功能，所以写下这个笔记。见笑。

servlet代码SendEmailServlet.java：

package servlet;import java.io.IOException;import java.io.PrintWriter;import java.util.concurrent.BlockingQueue;import java.util.concurrent.LinkedBlockingDeque;import java.util.concurrent.ThreadPoolExecutor;import java.util.concurrent.TimeUnit;import javax.servlet.ServletException;import javax.servlet.http.HttpServlet;import javax.servlet.http.HttpServletRequest;import javax.servlet.http.HttpServletResponse;/** * 发送邮件servlet * @author gandalf * */public class SendEmailServlet extends HttpServlet{private static final int corePoolSize = 1; // 线程池中所保存的核心线程数。private static final int maximumPoolSize = 4; //线程池允许创建的最大线程数。private static final long keepAliveTime = 0; //当前线程池线程总数大于核心线程数时，终止多余的空闲线程的时间。//邮件队列（线程共享）private static BlockingQueue<Runnable> emailQueue =  new LinkedBlockingDeque<Runnable>();//实例化线程池（线程共享）private static ThreadPoolExecutor threadPool= new ThreadPoolExecutor(corePoolSize, maximumPoolSize, keepAliveTime, TimeUnit.SECONDS, emailQueue,new ThreadPoolExecutor.AbortPolicy());@Overrideprotected void doGet(HttpServletRequest req, HttpServletResponse resp)throws ServletException, IOException {doPost(req, resp);}@Overrideprotected void doPost(HttpServletRequest req, HttpServletResponse resp)throws ServletException, IOException {//要发送的内容String content = req.getParameter("msg");//打印当前活动线程和队列大小System.out.println("--当前线程池大小【"+ threadPool.getPoolSize() + "】，当前队列大小【"+emailQueue.size()+"】");//加入队列threadPool.execute(new SendThread(content));//返回结果PrintWriter out = resp.getWriter();out.println("over");}@Overridepublic void destroy() {//关闭线程池threadPool.shutdown();super.destroy();}}

处理发送邮件的线程类SendThread.java:

package servlet;/** * 发送邮件线程 * @author gandalf * */public class SendThread implements Runnable{private String content;public SendThread (String content){this.content = content;}@Overridepublic void run() {try {//发送邮件。。。。Thread.sleep(1000);System.out.println("sendMail:"+content);} catch (InterruptedException e) {e.printStackTrace();}}}

web.xml配置：

 <servlet>      <servlet-name>sendMsg</servlet-name>      <servlet-class>servlet.SendEmailServlet</servlet-class>  </servlet>    <servlet-mapping>      <servlet-name>sendMsg</servlet-name>      <url-pattern>/sendMsg.do</url-pattern>  </servlet-mapping>

测试类，通过GET方式，向127.0.0.1/projectName/sendMsg.do发送请求：

package test;import java.io.BufferedReader;import java.io.InputStreamReader;import java.net.HttpURLConnection;import java.net.URL;public class ThreadPoolTest1 {public static void main(String[] args) {for(int i=0; i< 20; i++){new MyThread(i+"-t1").run();new MyThread(i+"-t2").run();new MyThread(i+"-t3").run();new MyThread(i+"-t4").run();}}}class MyThread implements Runnable{private String name;public MyThread(String name){this.name = name;}@Overridepublic void run() {try {Thread.sleep(500);System.out.println(name+"-----");URL getUrl = new URL("http://127.0.0.1/ThreadPool/sendMsg.do?msg=sendemailNO:"+name);    HttpURLConnection connection = (HttpURLConnection) getUrl                .openConnection();        // 进行连接，但是实际上get request要在下一句的connection.getInputStream()函数中才会真正发到服务器        connection.connect();        // 取得输入流，并使用Reader读取        BufferedReader reader = new BufferedReader(new InputStreamReader(connection.getInputStream(),"utf-8"));//设置编码,否则中文乱码                String lines;        while ((lines = reader.readLine()) != null){            System.out.println(lines);        }        reader.close();        // 断开连接        connection.disconnect();} catch (Exception e) {e.printStackTrace();}}}

测试结果：

--当前线程池大小【0】，当前队列大小【0】--当前线程池大小【1】，当前队列大小【0】sendMail:sendemailNO:0-t1--当前线程池大小【1】，当前队列大小【0】--当前线程池大小【1】，当前队列大小【1】sendMail:sendemailNO:0-t2--当前线程池大小【1】，当前队列大小【1】--当前线程池大小【1】，当前队列大小【2】sendMail:sendemailNO:0-t3--当前线程池大小【1】，当前队列大小【2】--当前线程池大小【1】，当前队列大小【3】sendMail:sendemailNO:0-t4--当前线程池大小【1】，当前队列大小【3】--当前线程池大小【1】，当前队列大小【4】sendMail:sendemailNO:1-t1--当前线程池大小【1】，当前队列大小【4】--当前线程池大小【1】，当前队列大小【5】sendMail:sendemailNO:1-t2--当前线程池大小【1】，当前队列大小【5】--当前线程池大小【1】，当前队列大小【6】sendMail:sendemailNO:1-t3--当前线程池大小【1】，当前队列大小【6】--当前线程池大小【1】，当前队列大小【7】sendMail:sendemailNO:1-t4--当前线程池大小【1】，当前队列大小【7】--当前线程池大小【1】，当前队列大小【8】sendMail:sendemailNO:2-t1sendMail:sendemailNO:2-t2sendMail:sendemailNO:2-t3