线程按顺序执行

public static void main(String[] args) {
//方法一，join()方法，强制性加入，使当前线程让出cpu,直到调用该方法的线程执行完：
final Thread t1 = new Thread(new Runnable() {

public void run() {
System.out.println("t1");
}
});
final Thread t2= new Thread(new Runnable() {

public void run() {
try {
t1.join();
System.out.println("t2");
} catch (InterruptedException e) {
e.printStackTrace();
}
}
});
final Thread t3 = new Thread(new Runnable() {
public void run() {
try {
t2.join();
System.out.println("t3");
} catch (Exception e) {
e.printStackTrace();
}

}
});

t2.start();
t3.start();
t1.start();
//方法二，newSingleThreadExecutor 线程池法：
final Thread t11 = new Thread(new Runnable() {

public void run() {
System.out.println("t11");
}
});
final Thread t22= new Thread(new Runnable() {

public void run() {
System.out.println("t22");
}
});
final Thread t33 = new Thread(new Runnable() {
public void run() {
System.out.println("t33");
}
});
ExecutorService executor = Executors.newSingleThreadExecutor();
executor.submit(t11);
executor.submit(t22);
executor.submit(t33);
executor.shutdown();

}