這里的join（）方法的作用到底是什么，如何實現(xiàn)讓進城快速結束呢？

代碼如下：（加粗加下劃線斜體部分...）

public class Stage extends Thread {
?@Override
?public void run() {
??ArmyRunnable armyTaskOfSuiDynasty=new ArmyRunnable();
??ArmyRunnable armyTaskOfRevolt=new ArmyRunnable();
??
??
??//創(chuàng)建軍隊線程
??Thread armyOfSuiDynasty=new Thread(armyTaskOfSuiDynasty, "隋軍");
??Thread armyOfRevolt=new Thread(armyTaskOfRevolt, "農(nóng)民起義軍");
??
??//啟動線程，讓軍隊開始作戰(zhàn)
??armyOfRevolt.start();
??armyOfSuiDynasty.start();
??
??try {
??Thread.sleep(50);
?} catch (InterruptedException e) {
??// TODO Auto-generated catch block
??e.printStackTrace();
?}
???armyTaskOfSuiDynasty.keeRunning=false;
?armyTaskOfRevolt.keeRunning=false;
?
?try {
??armyOfRevolt.join();
//??armyOfSuiDynasty.join();
?} catch (InterruptedException e) {
??// TODO Auto-generated catch block
??e.printStackTrace();
?}
?}
?public static void main(String[] args) {
??// TODO Auto-generated method stub
??/*new Stage().start();*/
??Stage st=new Stage();
??st.start();
?}
}