多线程（二）——四种线程池举例

太过爱你忘了你带给我的痛 2024-04-19 11:40 141阅读 0赞

### 一、可缓存的线程池——newCachedThreadPool ###

package thread.pool;
    
    import java.util.concurrent.ExecutorService;
    import java.util.concurrent.Executors;
    
    /**
     * 该类使用了缓存线程池,体现了线程池重复利用的特点
     * 用到的知识点有：匿名内部类只能使用外部被final修饰的变量
     * @author Administrator
     *
     */
    public class Test1 {
    	public static void main(String[] args) {
    		ExecutorService newCachedThreadPool = Executors.newCachedThreadPool();
    		for (int i = 0; i < 10; i++) {
    			int temp = i;
    			newCachedThreadPool.execute(new Runnable() {
    				@Override
    				public void run() {
    					System.out.println("线程"+Thread.currentThread().getName() + ",i:"+ temp);
    					
    				}
    			});
    		}
    		
    	}
    }

![watermark_type_ZmFuZ3poZW5naGVpdGk_shadow_10_text_aHR0cHM6Ly9ibG9nLmNzZG4ubmV0L1N1bl9vZl9SYWlueQ_size_16_color_FFFFFF_t_70][]

总结：线程池为无限大，当执行第二个任务时第一个任务已经完成，会复用执行第一个任务的线程，而不是每次创建新线程

### 二、可固定长度的线程池——**newFixedThreadPool** ###

package thread.pool;
    
    import java.util.concurrent.ExecutorService;
    import java.util.concurrent.Executors;
    
    /**
     * @author Administrator
     *
     */
    public class Test2 {
    	public static void main(String[] args) {
    		ExecutorService newCachedThreadPool = Executors.newFixedThreadPool(5);
    		for (int i = 0; i < 15; i++) {
    			int temp = i;
    			newCachedThreadPool.execute(new Runnable() {
    				@Override
    				public void run() {
    					System.out.println("线程"+Thread.currentThread().getName() + ",i:"+ temp);
    				}
    			});
    		}
    		
    	}
    }

![watermark_type_ZmFuZ3poZW5naGVpdGk_shadow_10_text_aHR0cHM6Ly9ibG9nLmNzZG4ubmV0L1N1bl9vZl9SYWlueQ_size_16_color_FFFFFF_t_70 1][]

总结：在指定长度内，线程一直重复利用

### 三、定时线程池——newScheduledThreadPool ###

package thread.pool;
    
    import java.util.concurrent.Executors;
    import java.util.concurrent.ScheduledExecutorService;
    import java.util.concurrent.TimeUnit;
    
    /**
     * @author Administrator
     *
     */
    public class Test3 {
    	public static void main(String[] args) {
    		ScheduledExecutorService newScheduledThreadPool = Executors.newScheduledThreadPool(3);
    		for (int i = 0; i < 10; i++) {
    			int temp = i;
    			newScheduledThreadPool.schedule(new Runnable() {
    				@Override
    				public void run() {
    					System.out.println("线程"+Thread.currentThread().getName() + ",i:"+ temp);
    				}
    			},3,TimeUnit.SECONDS);
    		}
    	}
    }

![watermark_type_ZmFuZ3poZW5naGVpdGk_shadow_10_text_aHR0cHM6Ly9ibG9nLmNzZG4ubmV0L1N1bl9vZl9SYWlueQ_size_16_color_FFFFFF_t_70 2][]

四、单线程的线程池——newSingleThreadExecutor

package thread.pool;
    
    import java.util.concurrent.ExecutorService;
    import java.util.concurrent.Executors;
    
    /**
     * @author Administrator
     *
     */
    public class Test3 {
    	public static void main(String[] args) {
    		ExecutorService newScheduledThreadPool = Executors.newSingleThreadExecutor();
    		for (int i = 0; i < 10; i++) {
    			int temp = i;
    			newScheduledThreadPool.execute(new Runnable() {
    				@Override
    				public void run() {
    					System.out.println("线程"+Thread.currentThread().getName() + ",i:"+ temp);
    				}
    			});
    		}
    	}
    }

![watermark_type_ZmFuZ3poZW5naGVpdGk_shadow_10_text_aHR0cHM6Ly9ibG9nLmNzZG4ubmV0L1N1bl9vZl9SYWlueQ_size_16_color_FFFFFF_t_70 3][]

![watermark_type_ZmFuZ3poZW5naGVpdGk_shadow_10_text_aHR0cHM6Ly9ibG9nLmNzZG4ubmV0L1N1bl9vZl9SYWlueQ_size_16_color_FFFFFF_t_70 4][]

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