WebSocket的进阶理解-CFANZ编程社区

一、内存图

1.堆、栈、方法区的配合示意图

2.一个数组的内存图

    public static void main(String[] args) {
        int[] arr1 = new int[3];
        System.out.println(arr1);
        System.out.println(arr1[1]);
        arr1[1] =100;
        System.out.println(arr1[1]);
    }

3.两个数组的内存图

    public static void main(String[] args) {
        int[] arr1 = new int[3];
        System.out.println(arr1);
        System.out.println(arr1[1]);
        arr[1] =100;
        System.out.println(arr1[1]);

        int[] arr2 = new int[3];
        System.out.println(arr2);//地址值
        System.out.println(arr2[1]);
        arr2[1] = 200;
        System.out.println("arr1[1] = " + arr1[1]);
        System.out.println("arr2[1] = " + arr2[1]);
    }

4.两个数组指向同一片空间内存图

    public static void main(String[] args) {
        int[] arr1 = new int[3];
        System.out.println(arr1);
        arr1[1] =100;

        int[] arr2 = arr1;
        System.out.println(arr2);//地址值
        arr2[1] = 200;
        System.out.println("arr1[1] = " + arr1[1]);
        System.out.println("arr2[1] = " + arr2[1]);
    }

二、二维数组

1.二维数组的定义格式

    public static void main(String[] args) {
        int[][] arr1 = new int[2][2];
        int[][] arr2 = new int[2][];

        System.out.println();
        String[][] arr3 = {{"唐僧","孙悟空","猪八戒","沙和尚"},{"刘备","关羽","张飞"},{"宋江"},{"贾宝玉","林黛玉"}};
    }

注：动态初始化数组长度必须定死，静态初始化数组长度不用定义好，每一个一维数组的长度根据实际存储的数据数来确定

2.获取二维数组的长度

    public static void main(String[] args) {
        String[][] arr1 = {{"唐僧","孙悟空","猪八戒","沙和尚"},{"刘备","关羽","张飞"},{"宋江"},{"贾宝玉","林黛玉"}};
        for (int i = 0; i < arr1.length; i++) {
            //获取每一个一维数组的长度
            System.out.println(arr1[i].length);
        }
    }

3.获取、存储二维数组中元素及遍历

    public static void main(String[] args) {
        //获取二维数组中的元素
        String[][] arr1 = {{"唐僧","孙悟空","猪八戒","沙和尚"},{"刘备","关羽","张飞"},{"宋江"},{"贾宝玉","林黛玉"}};
        System.out.println(arr1[0][1]);
        System.out.println(arr1[1][0]);
        System.out.println(arr1[2][0]);
        System.out.println(arr1[3][0]);
    }

多行列数对齐操作：ALT键不放鼠标下拉

    public static void main(String[] args) {
        String[][] arr1 = {{"唐僧","孙悟空","猪八戒","沙和尚"},{"刘备","关羽","张飞"},{"宋江"},{"贾宝玉","林黛玉"}};
        for (int i = 0; i < arr1.length; i++) {
            //获取每一个一维数组的长度
            System.out.print(arr1[i].length +" ");
            for (int j = 0; j < arr1[i].length; j++) {
                System.out.print(arr1[i][j]+" ");
            }
            System.out.println();
        }
    }