文章介绍4种办法，简略易懂，通过4个demo抛砖引玉。
1、在子线程中通过join()办法指定程序
通过join()办法使以后线程“阻塞”，期待指定线程执行结束后继续执行。
举例：在线程thread2中，加上一句thread1.join()，其意义在于，以后线程2运行到此行代码时会进入阻塞状态，直到线程thread1执行结束后，线程thread2才会持续运行，这就保障了线程thread1与线程thread2的运行程序。
public class ThreadJoinDemo {
public static void main(String[] args) throws InterruptedException {
final Thread thread1 = new Thread(new Runnable() {
@Override
public void run() {
System.out.println("关上冰箱！");
}
});
final Thread thread2 = new Thread(new Runnable() {
@Override
public void run() {
try {
thread1.join();
} catch (InterruptedException e) {
e.printStackTrace();
}
System.out.println("拿出一瓶牛奶！");
}
});
final Thread thread3 = new Thread(new Runnable() {
@Override
public void run() {
try {
thread2.join();
} catch (InterruptedException e) {
e.printStackTrace();
}
System.out.println("关上冰箱！");
}
});
//上面三行代码程序可随便调整，程序运行后果不受影响，因为咱们在子线程中通过“join()办法”曾经指定了运行程序。
thread3.start();
thread2.start();
thread1.start();
}
}运行后果：
关上冰箱！
拿出一瓶牛奶！
关上冰箱！2、在主线程中通过join()办法指定程序
简略说一下子线程与主线程的区别，子线程指的是产生在Thread外部的代码，主线程指的是产生在main函数中的代码，咱们能够在main函数中通过join()办法让主线程阻塞期待以达到指定程序执行的目标。
public class ThreadMainJoinDemo {
public static void main(String[] args) throws InterruptedException {
final Thread thread1 = new Thread(new Runnable() {
@Override
public void run() {
System.out.println("关上冰箱！");
}
});
final Thread thread2 = new Thread(new Runnable() {
@Override
public void run() {
System.out.println("拿出一瓶牛奶！");
}
});
final Thread thread3 = new Thread(new Runnable() {
@Override
public void run() {
System.out.println("关上冰箱！");
}
});
thread1.start();
thread1.join();
thread2.start();
thread2.join();
thread3.start();
}
}根底就不介绍了，多线程系列我博客教程写了很多了，这里举荐大家看看吧：https://www.javastack.cn/cate…
输入后果：
关上冰箱！
拿出一瓶牛奶！
关上冰箱！3、通过倒数计时器CountDownLatch实现
CountDownLatch通过计数器提供了更灵便的管制，只有检测到计数器为0以后线程就能够往下执行而不必管相应的thread是否执行结束。
public class ThreadCountDownLatchDemo {
private static CountDownLatch countDownLatch1 = new CountDownLatch(1);
private static CountDownLatch countDownLatch2 = new CountDownLatch(1);
public static void main(String[] args) {
final Thread thread1 = new Thread(new Runnable() {
@Override
public void run() {
System.out.println("关上冰箱！");
countDownLatch1.countDown();
}
});
final Thread thread2 = new Thread(new Runnable() {
@Override
public void run() {
try {
countDownLatch1.await();
System.out.println("拿出一瓶牛奶！");
countDownLatch2.countDown();
} catch (InterruptedException e) {
e.printStackTrace();
}
}
});
final Thread thread3 = new Thread(new Runnable() {
@Override
public void run() {
try {
countDownLatch2.await();
System.out.println("关上冰箱！");
} catch (InterruptedException e) {
e.printStackTrace();
}
}
});
//上面三行代码程序可随便调整，程序运行后果不受影响
thread3.start();
thread1.start();
thread2.start();
}
}输入后果：
关上冰箱！
拿出一瓶牛奶！
关上冰箱！4、通过创立单一化线程池newSingleThreadExecutor()实现
单线程化线程池(newSingleThreadExecutor)的长处，串行执行所有工作。
public class ThreadPoolDemo {
static ExecutorService executorService = Executors.newSingleThreadExecutor();
public static void main(String[] args) {
final Thread thread1 = new Thread(new Runnable() {
@Override
public void run() {
System.out.println("关上冰箱！");
}
});
final Thread thread2 =new Thread(new Runnable() {
@Override
public void run() {
System.out.println("拿出一瓶牛奶！");
}
});
final Thread thread3 = new Thread(new Runnable() {
@Override
public void run() {
System.out.println("关上冰箱！");
}
});
executorService.submit(thread1);
executorService.submit(thread2);
executorService.submit(thread3);
executorService.shutdown(); //应用结束记得敞开线程池
}
}输入后果：
关上冰箱！
拿出一瓶牛奶！
关上冰箱！起源：blog.csdn.net/jqc874789596/article/details/100557300
近期热文举荐：
1.1,000+ 道 Java面试题及答案整顿(2022最新版)
2.劲爆！Java 协程要来了。。。
3.Spring Boot 2.x 教程，太全了！
4.别再写满屏的爆爆爆炸类了，试试装璜器模式，这才是优雅的形式！！
5.《Java开发手册（嵩山版）》最新公布，速速下载！
感觉不错，别忘了顺手点赞+转发哦！
发表回复