映射< String，String&gt ;，如何同时打印"key string"和"key string".和“值字符串"一起

问题描述

限时删除！！

我是Java的新手，正在尝试学习Maps的概念.

I'm new to Java and is trying to learn the concept of Maps.

我想出了下面的代码.但是，我想同时打印出键字符串"和值字符串".

I have came up with the code below. However, I want to print out the "key String" and "value String" at the same time.

ProcessBuilder pb1 = new ProcessBuilder();
Map<String, String> mss1 = pb1.environment();
System.out.println(mss1.size());

for (String key: mss1.keySet()){
    System.out.println(key);
}

我只能找到只打印键字符串"的方法.

I could only find method that print only the "key String".

推荐答案

有多种方法可以实现此目的.这是三个.

There are various ways to achieve this. Here are three.

    Map<String, String> map = new HashMap<String, String>();
    map.put("key1", "value1");
    map.put("key2", "value2");
    map.put("key3", "value3");

    System.out.println("using entrySet and toString");
    for (Entry<String, String> entry : map.entrySet()) {
        System.out.println(entry);
    }
    System.out.println();

    System.out.println("using entrySet and manual string creation");
    for (Entry<String, String> entry : map.entrySet()) {
        System.out.println(entry.getKey() + "=" + entry.getValue());
    }
    System.out.println();

    System.out.println("using keySet");
    for (String key : map.keySet()) {
        System.out.println(key + "=" + map.get(key));
    }
    System.out.println();

输出

using entrySet and toString
key1=value1
key2=value2
key3=value3

using entrySet and manual string creation
key1=value1
key2=value2
key3=value3

using keySet
key1=value1
key2=value2
key3=value3

这篇关于映射< String，String&gt ;，如何同时打印"key string"和"key string".和“值字符串"一起的文章就介绍到这了，希望我们推荐的答案对大家有所帮助，也希望大家多多支持！

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