Java Thread join() 的用法

最新推荐文章于 2023-06-19 18:34:43 发布

转载最新推荐文章于 2023-06-19 18:34:43 发布 · 291 阅读

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本文详细解析了Java线程中的join()方法如何实现线程同步，通过示例展示了如何使用join()确保多线程任务按顺序执行。

Java Thread中， join() 方法主要是让调用改方法的thread完成run方法里面的东西后，在执行join()方法后面的代码。

package test;

class ThreadTesterA implements Runnable {  
	  
    private int counter;  
  
    public void run() {  
        while (counter <= 10) {  
            System.out.println("Counter = " + counter + " ");  
            counter++;  
        }  
        System.out.println();  
    }  
}  
  
class ThreadTesterB implements Runnable {  
  
    private int i;  
  
    public void run() {  
        while (i <= 10) {  
            System.out.println("i = " + i + " ");  
            i++;  
        }  
        System.out.println();  
    }  
}  
  
public class ThreadTester {  
    public static void main(String[] args) throws InterruptedException {  
        Thread t1 = new Thread(new ThreadTesterA());  
        Thread t2 = new Thread(new ThreadTesterB());  
        t1.start();  
        t1.join(); // wait t1 to be finished  
        t2.start();  
        t2.join(); // in this program, this may be removed  
    }  
}

如果去掉t1.join()这个语句过后，输出的书序是乱的，加上这个语句过后，就会按照顺序输出，从某种意义上说实现了同步。

Counter = 0 
Counter = 1 
Counter = 2 
Counter = 3 
Counter = 4 
Counter = 5 
Counter = 6 
Counter = 7 
Counter = 8 
Counter = 9 
Counter = 10 

i = 0 
i = 1 
i = 2 
i = 3 
i = 4 
i = 5 
i = 6 
i = 7 
i = 8 
i = 9 
i = 10