線程--join()方法的介紹

一、join()方法，官方描述waits for this thread to die 等待目前執行緒死亡；

## 

原始碼：

//無參，預設呼叫join(0)

public final void join() throws InterruptedException {

join(0);

}

 

//傳入兩時間millis 毫秒+nanos奈秒，表示等等millis+nanos,最後還是呼叫了方法3

public final synchronized void join(long millis, int nanos)

throws InterruptedException {

 

if (millis < 0) {

throw new IllegalArgumentException("timeout value is negative");

}

 

if (nanos < 0 || nanos > 999999) {

throw new IllegalArgumentException(

"nanosecond timeout value out of range");

}

 

if (nanos >= 500000 || (nanos != 0 && millis = = 0)) {

millis++;

}

 

join(millis);

}

#//方法3：傳入等時間，單位為毫秒，底層呼叫Object的wait(time)

public final synchronized void join(long millis)

throws InterruptedException {

long base = System.currentTimeMillis();

long now = 0;

 

if (millis < 0) {

throw new IllegalArgumentException("timeout value is negative");

}

 

##if (millis == 0) {

#while (isAlive()) {

wait(0);//表示一直等待，指導線程死亡

}

} else {

while ( isAlive()) {

long delay = millis - now;

#if (delay <= 0) {

break;

#}

wait(delay);

now = System.currentTimeMillis() - base;

}

##}

##}

# 

 

二、應用，例如幾個執行緒要依照一定順序執行

 

public class ThreadJoin extends Thread {

 

 

public void run(){

#try {

this.sleep(500);

System.out.println("["+new Date()+"]"+this.getName());

# 

} catch (InterruptedException e) {

e.printStackTrace();

}

}

# 

 

public static void main(String[] args) throws Exception {

int length = 5;

##Thread[] threads = new Thread[length];

for(int i=0; i

threads[i] = new ThreadJoin();

threads[i].start() ;

threads[i].join();//每個執行緒開啟後都會呼叫join

}

long endTime=System.currentTimeMillis();

}

}

/*

output:

[Sun Jun 11 13:40:42 CST 2017]Thread-0

[Sun Jun 11 13:40:43 CST 2017]Thread-1

[Sun Jun 11 13:40:43 CST 2017]Thread-2

[Sun Jun 11 13:40:44 CST 2017]Thread-3

[Sun Jun 11 13:40:44 CST 2017]Thread-4

 

## 

 

如果把join()註解

結果可能每次都不一樣

[Sun Jun 11 13:51:09 CST 2017]Thread-2

[Sun Jun 11 13:51:09 CST 2017]Thread-4

[Sun Jun 11 13:51:09 CST 2017]Thread-1

[Sun Jun 11 13 :51:09 CST 2017]Thread-3

[Sun Jun 11 13:51:09 CST 2017]Thread-0

#*/

### ## ####做事不能急，給自己一個大方向後總得一步一步來#############

以上是線程--join()方法的介紹的詳細內容。更多資訊請關注PHP中文網其他相關文章！

陳述：

本文內容由網友自願投稿，版權歸原作者所有。本站不承擔相應的法律責任。如發現涉嫌抄襲或侵權的內容，請聯絡admin@php.cn