我必须创建一个DeepParray2String方法，它需要一个二维int数组“x”并返回它的字符串表示形式

Question

public String deepArray2String(int[][] a1){

    StringBuffer result = new StringBuffer();
    for (int i = 0; i < a1.length; i++) {
        for (int j = 0; j < a1[i].length; j++) {
            result.append("[" + a1[i][j] + "]");
            if (j == a1.length && i != a1.length-1) {
                result.append(",");
            }
        }
    }
    return result;
}

System.out.println(deepArray2String(new int[][]{{1},{2},{4}}））；

输出应为[1]、[2]、[4]]

System.out.println(deepArray2String(new int[][]{{1},{2,3}}））；

System.out.println(deepArray2String(new int[][]{{5,3},{1},{-1,1}}））；

输出应为[[5,3],[1],[-1,1]]

Answer 1

没有必要推倒重来，Java已经在Java.util.Arrays中构建了一个静态方法来实现这一点。自动装箱意味着它可以处理任何基元类型的数组。

import java.util.Arrays;
import org.junit.Test;
import lombok.extern.slf4j.Slf4j;

@Slf4j
public class ExampleTest {

    @Test
    public void test() {
        log.info(Arrays.deepToString(new int[][] { { 1 }, { 2 }, { 4 } }));    
        log.info(Arrays.deepToString(new int[][] { { 1 }, { 2, 3 } }));    
        log.info(Arrays.deepToString(new int[][] {}));
        log.info(Arrays.deepToString(new int[][] { { 5, 3 }, { 1 }, { -1, 1 } }));
    }
}

结果

[main] INFO coaching.arrays.ExampleTest - [[1], [2], [4]]
[main] INFO coaching.arrays.ExampleTest - [[1], [2, 3]]
[main] INFO coaching.arrays.ExampleTest - []
[main] INFO coaching.arrays.ExampleTest - [[5, 3], [1], [-1, 1]]

参数的工作方式完全相同。

@Test
public void test() {
    int[][] a = new int[][] { { 1 }, { 2 }, { 4 } };
    log.info(Arrays.deepToString(a));

    int[][] a2 = new int[][] { { 1 }, { 2, 3 } };
    log.info(Arrays.deepToString(a2));

    int[][] a3 = new int[][] {};
    log.info(Arrays.deepToString(a3));

    int[][] a4 = new int[][] { { 5, 3 }, { 1 }, { -1, 1 } };
    log.info(Arrays.deepToString(a4));
}