Executors创建线程池的几种方式以及使用

Java通过Executors提供四种线程池，分别为：

 

1.newCachedThreadPool创建一个可缓存线程池，如果线程池长度超过处理需要，可灵活回收空闲线程，若无可回收，则新建线程。

 

2.newFixedThreadPool 创建一个定长线程池，可控制线程最大并发数，超出的线程会在队列中等待。

3.newScheduledThreadPool 创建一个定长线程池，支持定时及周期性任务执行。

 

4.newSingleThreadExecutor 创建一个单线程化的线程池，它只会用唯一的工作线程来执行任务，保证所有任务按照指定顺序(FIFO, LIFO, 优先级)执行。

 

 

直接上代码：

 

 1 import lombok.experimental.Delegate;
 2 
 3 import java.util.concurrent.ExecutorService;
 4 import java.util.concurrent.Executors;
 5 
 6 public class ThreadUtil {
 7 
 8     //维护一个单例线程
 9     private static final ThreadUtil threadUtil = new ThreadUtil();
10     
11     // 代理模式  这样可以直接调用父类中的方法
12     // public interface ExecutorService extends Executor
13     //public interface Executor {
14 
15     /**
16      * Executes the given command at some time in the future.  The command
17      * may execute in a new thread, in a pooled thread, or in the calling
18      * thread, at the discretion of the {@code Executor} implementation.
19      *
20      * @param command the runnable task
21      * @throws RejectedExecutionException if this task cannot be
22      * accepted for execution
23      * @throws NullPointerException if command is null
24      */
25     void execute(Runnable command);
26     }
27     
28     // 1.采用newCachedThreadPool创建线程池
29     @Delegate 
30     public ExecutorService cachedThreadPool = Executors.newCachedThreadPool();
31     
32     //2.采用newFixedThreadPool创建线程池
33     @Delegate
34     public ExecutorService service = Executors.newFixedThreadPool(3);
35     
36     //3.采用newScheduledThreadPool 创建一个定长线程池 支持定时及周期性任务执行。
37     // 使用方法： ThreadUtil.getInstance().schedule(new TestThread(),3, TimeUnit.SECONDS);
38     @Delegate
39     public ScheduledExecutorService newScheduledThreadPool = Executors.newScheduledThreadPool(2);
40     
41 
42     //4.采用newSingleThreadExecutor 创建一个单线程化的线程池
43     @Delegate
44     public ExecutorService newSingleThreadExecutor = Executors.newSingleThreadExecutor();
45 
46     public static ThreadUtil getInstance() {
47         return threadUtil;
48     }
49 
50 }

 1 @Override
 2 public String sendMsg() throws Exception {
 3     
 4     //把业务内容放在类中
 5     ThreadUtil.getInstance().execute(new TestThread());
 6     
 7     //或者这样直接写业务内容
 8     ThreadUtil.getInstance().execute( () -> {
 9 
10             System.out.println("222");
11 
12              // 打印线程的内存地址
13              System.out.println(System.identityHashCode(Thread.currentThread()));
14 
15              System.out.println(Thread.currentThread().getName());
16         }
17     );
18     return "ok";
19 }
20 
21 private class TestThread implements Runnable{
22 
23     @Override
24     public void run() {
25         System.out.println("111");
26 
27         System.out.println(Thread.currentThread().getName());
28 
29         System.out.println(System.identityHashCode(Thread.currentThread()));
30     }
31 }