【程序练习题】Java多线程

模拟三个老师同时分发80份学习笔记，每个老师相当于一个线程

public class Thread_subnotes {
    public static void main(String[] args) {
        TeacherToNotes t = new TeacherToNotes();
        new Thread(t, "老师1").start();
        new Thread(t, "老师2").start();
        new Thread(t, "老师3").start();
    }
}

class TeacherToNotes implements Runnable {
    private int notes = 80;
    public void run() {
        do {
            dispatchNotes(); // 调用售票方法
        } while (notes > 0);
    }
    private synchronized void dispatchNotes() {
        if (notes > 0) {
            try {
                Thread.sleep(10); // 经过的线程休眠10毫秒
            } catch (InterruptedException e) {
                e.printStackTrace();
            }
            System.out.println(Thread.currentThread().getName() + "---发出的笔记" + notes--);
        }
    }
}

编写10个线程，第一个线程从1加到10，第二个线程从11加到20…第十个线程从91加到100，最后再把十个线程结果相加。

public class Thread_add extends Thread {
    private int orginNum;
    public static int sum;

    public Thread_add(int startNum) {
        this.orginNum = startNum;
    }

    public static synchronized void add(int num) {
        sum += num;
    }

    public void run() {
        int sum = 0;
        for (int i = 0; i < 10; i++) {
            sum += orginNum + i;
        }
        add(sum);
    }

    public static void main(String[] args) throws Exception {
        Thread[] threadArray = new Thread[10];
        for (int i = 0; i < 10; i++) {
            threadArray[i] = new Thread_add(10 * i + 1);
            threadArray[i].start();//由jvm去调用run
            System.out.println("线程" + (i + 1) + "从：" + (10 * i + 1) + "开始");
        }
        for (int i = 0; i < 10; i++) {
            threadArray[i].join();
            System.out.println("Sum is : " + sum);
        }
    }
}