这一章节我们来讨论一下join。
1.什么是join？
阻塞当前线程，让.join的线程先做完。然后再继续当前线程
以下是api的解释：
A.join,在API中的解释是,阻塞当前线程B,直到A运行完毕并死掉,再运行B。
2.样例：
package com.ray.ch17;
public class Test {
public static void main(String[] args) throws InterruptedException {
System.out.println(Thread.currentThread().getName() + " start");
SleepThread sleepThread = new SleepThread("sleep");
Thread.sleep(2000);
JoinThread joinThread = new JoinThread(sleepThread, "join");
// joinThread.join();
System.out.println(Thread.currentThread().getName() + " end");
}
}
class SleepThread extends Thread {
public SleepThread(String name) {
super(name);
start();
}
@Override
public void run() {
try {
for (int i = 0; i < 5; i++) {
System.out.println(getName() + " SleepThread");
Thread.sleep(1000);
}
} catch (InterruptedException e) {
e.printStackTrace();
}
}
}
class JoinThread extends Thread {
private SleepThread sleepThread;
public JoinThread(SleepThread sleepThread, String name) {
super(name);
this.sleepThread = sleepThread;
start();
}
@Override
public void run() {
try {
System.out.println(getName() + " join start");
sleepThread.join();
System.out.println(getName() + " join end");
} catch (InterruptedException e) {
e.printStackTrace();
}
}
}
输出：
main start
sleep SleepThread
sleep SleepThread
sleep SleepThread
main end
join join start
sleep SleepThread
sleep SleepThread
join join end
package com.ray.ch17;
public class Test {
public static void main(String[] args) throws InterruptedException {
System.out.println(Thread.currentThread().getName() + " start");
SleepThread sleepThread = new SleepThread("sleep");
Thread.sleep(2000);
JoinThread joinThread = new JoinThread(sleepThread, "join");
joinThread.join();
System.out.println(Thread.currentThread().getName() + " end");
}
}
class SleepThread extends Thread {
public SleepThread(String name) {
super(name);
start();
}
@Override
public void run() {
try {
for (int i = 0; i < 5; i++) {
System.out.println(getName() + " SleepThread");
Thread.sleep(1000);
}
} catch (InterruptedException e) {
e.printStackTrace();
}
}
}
class JoinThread extends Thread {
private SleepThread sleepThread;
public JoinThread(SleepThread sleepThread, String name) {
super(name);
this.sleepThread = sleepThread;
start();
}
@Override
public void run() {
try {
System.out.println(getName() + " join start");
sleepThread.join();
System.out.println(getName() + " join end");
} catch (InterruptedException e) {
e.printStackTrace();
}
}
}
输出：
main start
sleep SleepThread
sleep SleepThread
sleep SleepThread
join join start
sleep SleepThread
sleep SleepThread
join join end
main end
上面两个代码的不同主要是体如今joinThread.join();是否被凝视。
对照上面的两个代码的输出，主要不同在于main end 的位置。当joinThread.join();的时候，因为须要先阻塞main方法的线程，先完毕joinThread所在线程，因此main end的位置会出现上面的变化。
还有一方面。我们从sleep和join两个线程输出的文字的位置也能够推导出上面的结论。
总结：这一章节我们简介了一下join。
这一章节就到这里，谢谢。
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