java - 二维数组转字符串输出（Arrays.deepToString()）

import java.util.Arrays;

public class DeepToStr {
    public static void main(String[] args) {
        final int SIZE = 4;
        int[][] matrix = new int[4][4];
        for (int i = 0; i < SIZE; i++) {
            for (int j = 0; j < SIZE; j++) {
                if (i == j) {
                    matrix[i][j] = 4;
                } else if (i < j) {
                    matrix[i][j] = 0;
                } else {
                    matrix[i][j] = 1;
                }
            }
        }
        System.out.println(Arrays.deepToString(matrix));
    }
}

输出结果：

[[4, 0, 0, 0], [1, 4, 0, 0], [1, 1, 4, 0], [1, 1, 1, 4]]