Java –如何打印数组

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在本文中,我们将向您展示几种打印Java数组的方法。

1. Arrays.toString 这是打印数组的最简单方法– Arrays.toString (自JDK 1.5起)

PrintArray.java

代码语言:javascript代码运行次数:0运行复制package com.mkyong.utils.print;

import java.util.Arrays;

public class PrintArray {

public static void main(String[] args) {

// array

String[] arrayStr = new String[]{"Java", "Node", "Python", "Ruby"};

System.out.println(Arrays.toString(arrayStr));

// Output : [Java, Node, Python, Ruby]

int[] arrayInt = {1, 3, 5, 7, 9};

System.out.println(Arrays.toString(arrayInt));

// Output : [1, 3, 5, 7, 9]

// 2d array, need Arrays.deepToString

String[][] deepArrayStr = new String[][]{

{"mkyong1", "mkyong2"}, {"mkyong3", "mkyong4"}};

System.out.println(Arrays.toString(deepArrayStr));

// Output : [[Ljava.lang.String;@23fc625e, [Ljava.lang.String;@3f99bd52]

System.out.println(Arrays.deepToString(deepArrayStr));

// Output : [[mkyong1, mkyong2], [mkyong3, mkyong4]

int[][] deepArrayInt = new int[][]{

{1, 3, 5, 7, 9}, {2, 4, 6, 8, 10}};

System.out.println(Arrays.toString(deepArrayInt));

// Output : [[I@3a71f4dd, [I@7adf9f5f]

System.out.println(Arrays.deepToString(deepArrayInt));

// Output : [[1, 3, 5, 7, 9], [2, 4, 6, 8, 10]]

}

} 输出量

代码语言:javascript代码运行次数:0运行复制[Java, Node, Python, Ruby]

[1, 3, 5, 7, 9]

[[Ljava.lang.String;@23fc625e, [Ljava.lang.String;@3f99bd52]

[[mkyong1, mkyong2], [mkyong3, mkyong4]]

[[I@3a71f4dd, [I@7adf9f5f]

[[1, 3, 5, 7, 9], [2, 4, 6, 8, 10]] 2. JDK 8流 在JDK 8中,我们可以将其转换为Stream并进行打印。

PrintArray.java

代码语言:javascript代码运行次数:0运行复制package com.mkyong.utils.print;

import java.util.Arrays;

public class PrintArray {

public static void main(String[] args) {

// array

String[] arrayStr = new String[]{"Java", "Node", "Python", "Ruby"};

Arrays.stream(arrayStr).forEach(System.out::println);

int[] arrayInt = {1, 3, 5, 7, 9};

Arrays.stream(arrayInt).forEach(System.out::println);

//2d array

String[][] deepArrayStr = new String[][]{

{"mkyong1", "mkyong2"}, {"mkyong3", "mkyong4"}};

Arrays.stream(deepArrayStr).flatMap(x -> Arrays.stream(x)).forEach(System.out::println);

int[][] deepArrayInt = new int[][]{

{1, 3, 5, 7, 9}, {2, 4, 6, 8, 10}};

Arrays.stream(deepArrayInt).flatMapToInt(x -> Arrays.stream(x)).forEach(System.out::println);

}

} 输出量

代码语言:javascript代码运行次数:0运行复制Java

Node

Python

Ruby

1

3

5

7

9

mkyong1

mkyong2

mkyong3

mkyong4

1

3

5

7

9

2

4

6

8

10 3.杰森 这是我最喜欢的方法,请使用Jackson2库以JSON格式的字符串打印任何内容。

PrintUtils.java

代码语言:javascript代码运行次数:0运行复制package com.mkyong.utils.print;

import com.fasterxml.jackson.core.JsonProcessingException;

import com.fasterxml.jackson.databind.ObjectMapper;

public class PrintUtils {

private static final ObjectMapper om = new ObjectMapper();

public static void print(Object object) {

String result;

try {

result = om.writerWithDefaultPrettyPrinter().writeValueAsString(object);

System.out.println(result);

} catch (JsonProcessingException e) {

e.printStackTrace();

}

}

} PrintArray.java

代码语言:javascript代码运行次数:0运行复制package com.mkyong.utils.print;

public class PrintArray {

public static void main(String[] args) {

//array

String[] arrayStr = new String[]{"Java", "Node", "Python", "Ruby"};

PrintUtils.print(arrayStr);

int[] arrayInt = {1, 3, 5, 7, 9};

PrintUtils.print(arrayInt);

//2d array

String[][] deepArrayStr = new String[][]{

{"mkyong1", "mkyong2"}, {"mkyong3", "mkyong4"}};

PrintUtils.print(deepArrayStr);

int[][] deepArrayInt = new int[][]{

{1, 3, 5, 7, 9}, {2, 4, 6, 8, 10}};

PrintUtils.print(deepArrayInt);

}

} 输出量

代码语言:javascript代码运行次数:0运行复制[ "Java", "Node", "Python", "Ruby" ]

[ 1, 3, 5, 7, 9 ]

[ [ "mkyong1", "mkyong2" ], [ "mkyong3", "mkyong4" ] ]

[ [ 1, 3, 5, 7, 9 ], [ 2, 4, 6, 8, 10 ] ] 参考文献 Steam Javasoc 数组JavaDoc 杰克逊2将Java对象转换为JSON 杰克逊2官方网站 标签:

数组

Java

翻译自: https://mkyong.com/java/java-how-to-print-an-array/

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