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();    }