格式:以加入A线程为例
线程对象B.join() 无参数,则A线程一直暂停,直到B线程运行结束。
线程对象B.join(时间t) 有参数,则A线程每隔t时间暂停一次,直到B线程运行结束。
关于while(true)无限循环,参考https://blog.csdn.net/m1598306557/article/details/78176576
案例:线程A达到20%时,线程B加入
public class Demo extends JFrame {
private Thread threadA;//定义线程
private Thread threadB;
final JProgressBar progressBar1 = new JProgressBar();//进度条
final JProgressBar progressBar2 = new JProgressBar(); public Demo() {
setBounds(100, 100, 200, 100);
setDefaultCloseOperation(WindowConstants.EXIT_ON_CLOSE);
getContentPane().add(progressBar1, BorderLayout.NORTH);
getContentPane().add(progressBar2, BorderLayout.SOUTH);
progressBar1.setStringPainted(true);//显示数字
progressBar2.setStringPainted(true);
//使用匿名内部类实现Runnable接口
threadA = new Thread(new Runnable() {
int count = 0;//进度数据 public void run() {
while (true) {//无限循环,一般在不知道循环次数时使用
progressBar1.setValue(++count);
try {
Thread.sleep(100);//休眠0.1s
if (count==20){
threadB.join();//线程B加入,
}
} catch (InterruptedException e) {
e.printStackTrace();
}
if (count == 100)
break;
}
}
});
threadA.start(); threadB = new Thread(new Runnable() {
int count = 0;//进度数据 public void run() {
while (true) {
progressBar2.setValue(++count);
try {
Thread.sleep(100);
} catch (InterruptedException e) {
e.printStackTrace();
}
if (count == 100)
break;
}
}
});
threadB.start(); setVisible(true);
} public static void main(String[] args) {
new Demo();
}
}