初学者入门
把这些代码当示例存下来
Runnable

java//Create multiple threads.
class NewThread implements Runnable {
        String name; // name of thread
        Thread t;
        NewThread(String threadname) {
             name = threadname;
             t = new Thread(this, name);
             System.out.println("New thread: " + t);
             t.start(); // Start the thread
             }

     // This is the entry point for thread.
     public void run() {
         try {
             for(int i = 5; i > 0; i--) {
                System.out.println(name + ": " + i);
                Thread.sleep(1000);
                 }
             } catch (InterruptedException e) {
             System.out.println(name + "Interrupted");
             }
         System.out.println(name + " exiting.");
     }
    }

public class TestDemo {
 public static void main(String args[]) {
     new NewThread("One"); // start threads
     new NewThread("Two");
     new NewThread("Three");
     try {
         // wait for other threads to end
         Thread.sleep(10000);
     } catch (InterruptedException e) {
         System.out.println("Main thread Interrupted");
     }
     System.out.println("Main thread exiting.");
 }
}

Thread方式

javaclass NewThread extends Thread {
    NewThread() {
        // Create a new, second thread
        super("Demo Thread");
        System.out.println("Child thread: " + this);
        start(); // Start the thread
    }

    // This is the entry point for the second thread.
    public void run() {
        try {
            for(int i = 5; i > 0; i--) {
                System.out.println("Child Thread: " + i);
                Thread.sleep(500);
            }
        } catch (InterruptedException e) {
            System.out.println("Child interrupted.");
        }
        System.out.println("Exiting child thread.");
    }
}

class ExtendThread {
    public static void main(String args[]) {
        new NewThread(); // create a new thread
        try {
            for(int i = 5; i > 0; i--) {
                System.out.println("Main Thread: " + i);
                Thread.sleep(1000);
           }
        } catch (InterruptedException e) {
            System.out.println("Main thread interrupted.");
        }
        System.out.println("Main thread exiting.");
    }
}