java的线程池的使用

1、线程池的创建

　　1、首先创建一个类，然后实现Runnable接口

public class ExectorTest implements Runnable {}

　　2、首先声明一个线程池的全局变量

public class ExectorTest implements Runnable {
        //线程池
        private ExecutorService executorPool;
}

　　3、然后在run()方法中，创建线程池实例，创建线程池的时候，切记创建守护线程，这样可以防止你的服务停止后，服务的线程还没停止，就是tomcat的进程还在的情况出现。

public class ExectorTest implements Runnable {
        //线程池
        private ExecutorService executorPool;

        @Override
        public void run() {
                //  创建线程池，设置为守护进程，可以和主线程一起关闭
               this.executorPool = Executors.newFixedThreadPool(this.numThreads, new ThreadFactory() {
               @Override
               public Thread newThread(Runnable r) {
                    Thread thread = Executors.defaultThreadFactory().newThread(r);
                    thread.setDaemon(true);
                    return thread;
               }
           });
        }
}

　　4、然后我们需要循环需要处理的方法个数，在循环中调用线程池的方法

public class ExectorTest implements Runnable {
        //线程池
        private ExecutorService executorPool;

        @Override
        public void run() {
                //  创建线程池，设置为守护进程，可以和主线程一起关闭
               this.executorPool = Executors.newFixedThreadPool(this.numThreads, new ThreadFactory() {
               @Override
               public Thread newThread(Runnable r) {
                    Thread thread = Executors.defaultThreadFactory().newThread(r);
                    thread.setDaemon(true);
                    return thread;
               }
           });  

               //循环处理的方法
               List<String> handleList = new ArrayList<String>();
               for (String handler:handleList) {
                   this.executorPool.submit(new Handler());
               }
        }
}

　　5、将处理的方法贴上

public class ExectorTest implements Runnable {
        //线程池
        private ExecutorService executorPool;

        @Override
        public void run() {
                //  创建线程池，设置为守护进程，可以和主线程一起关闭
               this.executorPool = Executors.newFixedThreadPool(this.numThreads, new ThreadFactory() {
               @Override
               public Thread newThread(Runnable r) {
                    Thread thread = Executors.defaultThreadFactory().newThread(r);
                    thread.setDaemon(true);
                    return thread;
               }
           });  

               //循环处理的方法
               List<String> handleList = new ArrayList<String>();
               for (String handler:handleList) {
                   this.executorPool.submit(new Handler());
               }
        }

         /**
           * 数据处理线程
           */
        public static class Handler implements Runnable {

              public Handler() {}

              @Override
              public void run() {
                  //处理数据的方法
              }
        }
}

2、线程池的关闭

　　6、最后补全停止线程池的方法，@PreDestroy方法是在spring销毁之前会调用的方法

public class ExectorTest implements Runnable {
        //线程池
        private ExecutorService executorPool;

        @Override
        public void run() {
                //  创建线程池，设置为守护进程，可以和主线程一起关闭
               this.executorPool = Executors.newFixedThreadPool(this.numThreads, new ThreadFactory() {
               @Override
               public Thread newThread(Runnable r) {
                    Thread thread = Executors.defaultThreadFactory().newThread(r);
                    thread.setDaemon(true);
                    return thread;
               }
           });  

               //循环处理的方法
               List<String> handleList = new ArrayList<String>();
               for (String handler:handleList) {
                   this.executorPool.submit(new Handler());
               }
        }

         /**
           * 数据处理线程
           */
        public static class Handler implements Runnable {

              public Handler() {}

              @Override
              public void run() {
                  //处理数据的方法
              }
        }

        @PreDestroy
        public void shutdown() {
            // 关闭线程池，会等待线程的执行完成
            if (this.executorPool != null) {
                //  关闭线程池
                this.executorPool.shutdown();

                //  等待关闭完成, 等待五秒
                try {
                    if (!this.executorPool.awaitTermination(5, TimeUnit.SECONDS)) {
                        log.info("Timed out waiting for consumer threads to shut down, exiting uncleanly!!");
                    }
                } catch (InterruptedException e) {
                    log.info("Interrupted during shutdown, exiting uncleanly!!");
                }
            }

        }
}