Java遍历Map集合的三种方法

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package com.xqnode;import java.util.*;/** * 遍历map集合的三种方法 * Created by xiaqing on 2017/10/21. */public class RunMain {    public static void main(String[] args){        System.out.println("Hello World!");        Map<String,Object> map = new HashMap <>();        map.put("a","a");        map.put("b",1);        map.put("c",false);        //方法一        Iterator <String> keyIterator = map.keySet().iterator();        while(keyIterator.hasNext()){            String key = keyIterator.next();            Object value = map.get(key);            System.out.println("key:"+key+",value:"+value);        }        //方法二        Iterator <Map.Entry <String, Object>> entryIterator = map.entrySet().iterator();        while (entryIterator.hasNext()){            Map.Entry <String, Object> mapEntry = entryIterator.next();            String key = mapEntry.getKey();            Object value = mapEntry.getValue();            System.out.println("key:"+key+",value:"+value);        }        //方法三        Collection <Object> values = map.values();        for (Object o: values) {            System.out.println(o);        }    }}

Java8 lambda表达式：

map.forEach((k,v) -> System.out.println("key:"+k+",value:"+v));

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