多线程基础算法:让10个线程按顺序打印出0123456789

思路：
1.起始变量：0和10（或者9）
2.10个线程，每个线程绑定一个数字
代码实现如下：

class Main {

    //锁
    private static Object lock = new Object();

    static int startNum = 0;
    static int endNum = 10;

    public static void main(String[] args) {

        ThreadPrint[] arr = new ThreadPrint[endNum];
        //不按打印顺序创建线程
        for (int i = arr.length - 1; i >= 0; i--) {
            arr[i] = new ThreadPrint(i);
            arr[i].start();
        }
    }

    private static class ThreadPrint extends Thread {

        private int printNum;   //获取自己需要打印的数字

        ThreadPrint(int printNum) {
            this.printNum = printNum;
        }
        @Override
        public void run() {
            synchronized (lock) {

                while (startNum < endNum) {
                    if (startNum == printNum) {

                        System.out.print(printNum);
                        startNum++;

                        if(startNum == endNum) {
                            System.out.print("\n打印结束");
                        }
                        lock.notifyAll();
                    } else {
                        try {
                            lock.wait();
                        } catch (InterruptedException e) {
                            //线程被打断
                            e.printStackTrace();
                        }
                    }
                }

            }
        }
    }
}