• 注意一点，数组每行可以不等长
• 可以两种写法，直接枚举初始化，或者new type [len1][len2]...

import java.util.Arrays;public class Myarray {public static void main(String[] args){// 一维数组声明int arr1 [] = new int[3];int [] arr2 = {4,5,6};arr1[0] = 0;arr1[1] = 1;arr1[2] = 2;for(int i = 0; i < arr1.length; ++i) {System.out.println(arr1[i]);System.out.println(arr2[i]);}// API arraycopyint source [] = {1,2,3}, dest [] = {4,5,6,7};System.arraycopy(source, 1, dest, 2, 2);// 从source 的 pos 1 开始 拷贝到 dest 的 pos 2， 复制 len = 2 个for(int i : dest)System.out.println(i);// 4,5,2,3// sortArrays.sort(dest);for(int i : dest)System.out.println(i);// 2,3,4,5// 二维数组int arr2d1 [][] = {{1,2},{3},{4,5}};//可以每行不一样长for(int i = 0; i <arr2d1.length; ++i){for(int v : arr2d1[i])System.out.print(v);System.out.print("\n");}int [][] arr2d2 = new int [2][3];//2行3列for(int i = 0; i <arr2d2.length; ++i){for(int v : arr2d2[i])System.out.print(v);//不初始化，默认为 0System.out.print("\n");}// 多维数组int arr3d1 [][][] = {{{1,2},{3}},{{4,5},{6,7},{8}}};int [][][] arr3d2 = new int [2][3][4];}
}