多线程循环输出两个数组（多线程实践）

用两个线程将两个数组轮流输出(数组可能不等长)。输入a1[1,2,3,4],a2[5,6,7,8,9] 输出1,5,2,6,3,7,4,8

轮流输出两个数的实现方法有多种，最简单的可以采用Synchronized来同步实现，如果这是面试场合的题目的话，恐怕不是面试官想要的答案，因为同步意味着效率不高，在这给出利用volatile可见性来实现的轮流输出的功能

public class Main {
    //开关
    volatile boolean sw = true;
    //判断是否有数组已输出完
    volatile boolean over = false;

    public static void main(String[] args) {
        int[] a1 = new int[]{1, 2, 3, 4};
        int[] a2 = new int[]{5, 6, 7, 8, 9};
        Main test = new Main();
        test.process(a1, a2);
    }

    private void process(int[] a1, int[] a2) {
        Thread t1 = new Thread(() -> {
            for (int i = 0; i < a1.length; i++) {
                while (sw != true && over == false) {
                    //自旋；可以加睡眠时间
                }
                if (sw == true) {
                    try {
                        Thread.sleep(100);
                    } catch (InterruptedException e) {
                        e.printStackTrace();
                    }
                    System.out.println(a1[i]);
                    sw = false;
                }
            }
            over = true;
        });
        Thread t2 = new Thread(() -> {
            for (int i = 0; i < a2.length; i++) {
                while (sw != false && over == false) {
                    //自旋
                }
                if (sw == false || over == true) {
                    try {
                        Thread.sleep(100);
                    } catch (InterruptedException e) {
                        e.printStackTrace();
                    }
                    System.out.println(a2[i]);
                    sw = true;
                }
            }
            over = true;
        });
        t1.start();
        t2.start();
    }