先上代码

新建一个thread,代码如下:

package com.thread.test;

public class mythread extends thread {

private string name;

public mythread(string name) {

this.name = name;

}

@override

public void run() {

for (int i = 0; i < 100; i++) {

system.out.println(name+"["+i+"]");

}

super.run();

}

}

之后新建测试类,代码如下:

package com.thread.test;

/*

* 0-50执行的是主线程,50-100执行的是a线程,并且将a线程完全执行完后才继续执行主线程

*/

public class threaddemo{

public static void main(string[] args) {

mythread t = new mythread("a");

t.start();

for (int i = 0; i < 100; i++) {

if (i>50) {

try {

t.join();

} catch (interruptedexception e) {

e.printstacktrace();

}

}

system.out.println("主线程"+"["+i+"]");

}

}

}

下面是java platform se8 api中对thread中join方法的解释:

public final void join(long millis)

throws interruptedexceptionwaits at most millis milliseconds for this thread to die. a timeout of 0 means to wait forever.

this implementation uses a loop of this.wait calls conditioned on this.isalive. as a thread terminates the this.notifyall method is invoked. it is recommended that applications not use wait, notify, or notifyall on thread instances.

parameters:

millis - the time to wait in milliseconds

throws:

illegalargumentexception - if the value of millis is negative

interruptedexception - if any thread has interrupted the current thread. the interrupted status of the current thread is cleared when this exception is thrown.

先上代码

新建一个thread,代码如下:

package com.thread.test;

public class mythread extends thread {

private string name;

public mythread(string name) {

this.name = name;

}

@override

public void run() {

for (int i = 0; i < 100; i++) {

system.out.println(name+"["+i+"]");

}

super.run();

}

}

之后新建测试类,代码如下:

package com.thread.test;

/*

* 0-50执行的是主线程,50-100执行的是a线程,并且将a线程完全执行完后才继续执行主线程

*/

public class threaddemo{

public static void main(string[] args) {

mythread t = new mythread("a");

t.start();

for (int i = 0; i < 100; i++) {

if (i>50) {

try {

t.join();

} catch (interruptedexception e) {

e.printstacktrace();

}

}

system.out.println("主线程"+"["+i+"]");

}

}

}

下面是java platform se8 api中对thread中join方法的解释:

public final void join(long millis)

throws interruptedexceptionwaits at most millis milliseconds for this thread to die. a timeout of 0 means to wait forever.

this implementation uses a loop of this.wait calls conditioned on this.isalive. as a thread terminates the this.notifyall method is invoked. it is recommended that applications not use wait, notify, or notifyall on thread instances.

parameters:

millis - the time to wait in milliseconds

throws:

illegalargumentexception - if the value of millis is negative

interruptedexception - if any thread has interrupted the current thread. the interrupted status of the current thread is cleared when this exception is thrown.

我自己的理解就是会强行进入使用join方法的线程，其他线程等待该线程完全执行完后才会进来。

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