blocks|key|1512707|text|如果可能，更简单的解决方案是先启动B，然后启动b.join();，然后在客户端代码中对A执行相同的操作：|type|unstyled|depth|inlineStyleRanges|offset|length|style|CODE|entityRanges|data|1512708|b.start();
b.join();
a.start();
a.join();|code-block|syntax|javascript|1512709|启动一个线程是没有意义的，因为它只是启动并连接到另一个踏步上，然后再继续。|1512710|entityMap^0|H|1|N|9|17|1|0|0|0^^$0|@$1|2|3|4|5|6|7|O|8|@$9|P|A|Q|B|C]|$9|R|A|S|B|C]|$9|T|A|U|B|C]]|D|@]|E|$]]|$1|F|3|G|5|H|7|V|8|@]|D|@]|E|$I|J]]|$1|K|3|L|5|6|7|W|8|@]|D|@]|E|$]]|$1|M|3|-4|5|6|7|X|8|@]|D|@]|E|$]]]|N|$]]

If possible, a simpler solution would be to start <code>B</code> first, then <code>b.join();</code>, and do the same for <code>A</code> in the client code:

<pre><code>b.start();
b.join();
a.start();
a.join();
</code></pre>

There is no sense in starting a thread for it to just fire up and join on another tread before proceeding.

blocks|key|492140|text|同样的交易：|type|unstyled|depth|inlineStyleRanges|entityRanges|data|492141|class+A+extends+Thread{
++++private+Thread+someThread;
++++A(Thread+t){
++++++++someThread=t;
++++}
++++public+void+run(){
++++++++someThread.start();
++++++++someThread.join();
++++++++//+proceed
++++}
}
class+B+extends+Thread{
++++public+void+run(){
++++++++....
++++}
}|code-block|syntax|javascript|492142|entityMap^0|0|0^^$0|@$1|2|3|4|5|6|7|I|8|@]|9|@]|A|$]]|$1|B|3|C|5|D|7|J|8|@]|9|@]|A|$E|F]]|$1|G|3|-4|5|6|7|K|8|@]|9|@]|A|$]]]|H|$]]

Same deal:

<pre><code>class A extends Thread{
 private Thread someThread;
 A(Thread t){
 someThread=t;
 }
 public void run(){
 someThread.start();
 someThread.join();
 // proceed
 }
}
class B extends Thread{
 public void run(){
 ....
 }
}
</code></pre>

blocks|key|4558829|text|class+A+extends+Thread{

++++private+Thread+someThread;

++++B(Thread+t){
++++++++someThread=t;
++++}
++++public+void+run(){
++++++++someThread.join()
++++++++//do+stuff
++++}
}

class+B+extends+Thread{

++++public+void+run(){
++++++++....
++++}
}|type|code-block|depth|inlineStyleRanges|entityRanges|data|syntax|javascript|4558830|unstyled|entityMap^0|0^^$0|@$1|2|3|4|5|6|7|G|8|@]|9|@]|A|$B|C]]|$1|D|3|-4|5|E|7|H|8|@]|9|@]|A|$]]]|F|$]]

<pre><code>class A extends Thread{

 private Thread someThread;

 B(Thread t){
 someThread=t;
 }
 public void run(){
 someThread.join()
 //do stuff
 }
}

class B extends Thread{

 public void run(){
 ....
 }
}
</code></pre>

blocks|key|4558850|text|Thread+b+=+new+B();
b.start();
b.join();|type|code-block|depth|inlineStyleRanges|entityRanges|data|syntax|javascript|4558851|但是你为什么要这么做呢？线程的思想是并行地做事情。为什么要启动一个线程，然后立即等待它完成？只需在A中执行B中的内容即可。|unstyled|4558852|entityMap^0|0|0^^$0|@$1|2|3|4|5|6|7|I|8|@]|9|@]|A|$B|C]]|$1|D|3|E|5|F|7|J|8|@]|9|@]|A|$]]|$1|G|3|-4|5|F|7|K|8|@]|9|@]|A|$]]]|H|$]]

<pre><code>Thread b = new B();
b.start();
b.join();
</code></pre>

But why would you want to? The idea of threads is to do things in parallel. Why would you start a thread and immediately wait for it to finish? Just execute the stuff from B in place in A.

blocks|key|4558911|text|您可以使用join()来等待任何线程。|type|unstyled|depth|inlineStyleRanges|entityRanges|data|4558912|final+Thread+a+=+Thread.currentThread();
new+Thread(new+Runnable()+{
++++public+void+run()+{
++++++++//+do+something
++++++++a.join();
++++++++//+calling+thread+finished.
++++}
+}).start();
+//+do+something.|code-block|syntax|javascript|4558913|entityMap^0|0|0^^$0|@$1|2|3|4|5|6|7|I|8|@]|9|@]|A|$]]|$1|B|3|C|5|D|7|J|8|@]|9|@]|A|$E|F]]|$1|G|3|-4|5|6|7|K|8|@]|9|@]|A|$]]]|H|$]]

You can use join() to wait for any thread.

<pre><code>final Thread a = Thread.currentThread();
new Thread(new Runnable() {
 public void run() {
 // do something
 a.join();
 // calling thread finished.
 }
 }).start();
 // do something.
</code></pre>

blocks|key|1512741|text|找到下面的例子，了解如何反向执行线程。|type|unstyled|depth|inlineStyleRanges|entityRanges|data|1512742|对于这种情况，我们可以使用join方法。|1512743|++++package+interview.thread;
+++++public+class+RevarseThreadExcute+{
++++public+static+void+main(String[]+args)+throws+InterruptedException+{
+++Thread+t3+=+new+Thread(new+Runnable()+{
++++@Override
++++++++++++public+void+run()+{

++++++++++++++++for+(int+i+=+0;+i+<+10;+i%2B%2B)+{
++++++++++++++++++++System.out.println("Thread+3+="+%2B+i);

++++++++++++++++}
++++++++++++}
++++++++});
++++++++Thread+t2+=+new+Thread(new+Runnable()+{

++++++++++++@Override
++++++++++++public+void+run()+{
+++++++++++++++try+{
++++++++++++++++t3.join();
++++++++++++}+catch+(InterruptedException+e)+{
++++++++++++++++//+TODO+Auto-generated+catch+block
++++++++++++++++e.printStackTrace();
++++++++++++}
++++++++++++++++for+(int+i+=+0;+i+<+10;+i%2B%2B)+{
++++++++++++++++++++System.out.println("Thread+2+="+%2B+i);

++++++++++++++++}
++++++++++++}
++++++++});

++++++++Thread+t1+=+new+Thread(new+Runnable()+{

++++++++++++@Override
++++++++++++public+void+run()+{
++++++++++++++++try+{
++++++++++++++++++++t3.join();
++++++++++++++++++++t2.join();
++++++++++++++++}+catch+(InterruptedException+e)+{
++++++++++++++++++++//+TODO+Auto-generated+catch+block
++++++++++++++++++++e.printStackTrace();
++++++++++++++++}
++++++++++++++++for+(int+i+=+0;+i+<+10;+i%2B%2B)+{
++++++++++++++++++++System.out.println("Thread+1+="+%2B+i);

++++++++++++++++}
++++++++++++}
++++++++});

++++++++t1.start();
++++++++t2.start();
++++++++t3.start();
++++}


}|code-block|syntax|javascript|1512744|输出：|1512745|Thread+3+=0
Thread+3+=1
Thread+3+=2
Thread+3+=3
Thread+3+=4
Thread+3+=5
Thread+3+=6
Thread+3+=7
Thread+3+=8
Thread+3+=9
Thread+2+=0
Thread+2+=1
Thread+2+=2
Thread+2+=3
Thread+2+=4
Thread+2+=5
Thread+2+=6
Thread+2+=7
Thread+2+=8
Thread+2+=9
Thread+1+=0
Thread+1+=1
Thread+1+=2
Thread+1+=3
Thread+1+=4
Thread+1+=5
Thread+1+=6
Thread+1+=7
Thread+1+=8
Thread+1+=9|1512746|entityMap^0|0|0|0|0|0^^$0|@$1|2|3|4|5|6|7|O|8|@]|9|@]|A|$]]|$1|B|3|C|5|6|7|P|8|@]|9|@]|A|$]]|$1|D|3|E|5|F|7|Q|8|@]|9|@]|A|$G|H]]|$1|I|3|J|5|6|7|R|8|@]|9|@]|A|$]]|$1|K|3|L|5|F|7|S|8|@]|9|@]|A|$G|H]]|$1|M|3|-4|5|6|7|T|8|@]|9|@]|A|$]]]|N|$]]

Find below example for how to reverse execute the thread.?

We can use join method for this case.

<pre><code> package interview.thread;
 public class RevarseThreadExcute {
 public static void main(String[] args) throws InterruptedException {
 Thread t3 = new Thread(new Runnable() {
 @Override
 public void run() {

 for (int i = 0; i &lt; 10; i++) {
 System.out.println("Thread 3 =" + i);

 }
 }
 });
 Thread t2 = new Thread(new Runnable() {

 @Override
 public void run() {
 try {
 t3.join();
 } catch (InterruptedException e) {
 // TODO Auto-generated catch block
 e.printStackTrace();
 }
 for (int i = 0; i &lt; 10; i++) {
 System.out.println("Thread 2 =" + i);

 }
 }
 });

 Thread t1 = new Thread(new Runnable() {

 @Override
 public void run() {
 try {
 t3.join();
 t2.join();
 } catch (InterruptedException e) {
 // TODO Auto-generated catch block
 e.printStackTrace();
 }
 for (int i = 0; i &lt; 10; i++) {
 System.out.println("Thread 1 =" + i);

 }
 }
 });

 t1.start();
 t2.start();
 t3.start();
 }


}
</code></pre>

outpot:

<pre><code>Thread 3 =0
Thread 3 =1
Thread 3 =2
Thread 3 =3
Thread 3 =4
Thread 3 =5
Thread 3 =6
Thread 3 =7
Thread 3 =8
Thread 3 =9
Thread 2 =0
Thread 2 =1
Thread 2 =2
Thread 2 =3
Thread 2 =4
Thread 2 =5
Thread 2 =6
Thread 2 =7
Thread 2 =8
Thread 2 =9
Thread 1 =0
Thread 1 =1
Thread 1 =2
Thread 1 =3
Thread 1 =4
Thread 1 =5
Thread 1 =6
Thread 1 =7
Thread 1 =8
Thread 1 =9
</code></pre>

I know that I can use the following to have thread B waiting for thread A to finish before proceeding:

<pre><code>class A extends Thread{
 public void run(){
 ....
 }
}
class B extends Thread{
 private Thread someThread;
 B(Thread t){
 someThread=t;
 }
 public void run(){
 someThread.join();
 ...//then proceed
 }
}
</code></pre>

But how can I do this in the <code>run()</code> of <code>A</code> to call <code>B</code> and then wait it finish before proceeding? That is, I want something like

<pre><code>class A extends Thread{
 private Thread someThread;
 B(Thread t){
 someThread=t;
 }
 public void run(){
 //*how to start B and wait it finish?
 ...//then proceed
 }
}
class B extends Thread{
 public void run(){
 ....
 }
}
</code></pre>

reverse using of Thread.join() in java

翻译质量差，导致语言生硬或混乱。

没有提供实际的解决方法或示例。

解答不清晰，无法理解或解决问题。

页面排版不美观，阅读体验差。

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我知道我可以使用以下代码让线程B等待线程A完成，然后再继续：class A extends Thread{    public void run(){        ....    }}class B extends Thread{    private Thread someThread;    B(Thread t){        someThread=t;    }    public v

问在java中反向使用Thread.join()
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回答 6

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问在java中反向使用Thread.join()
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