map 遍历的几种方法

public static void main(String[] args) {Map<String,String> map = new HashMap<String,String>();map.put("a", "1");map.put("b", "2");map.put("c", "3");map.put("d", "4");map.put("e", "5");//同时遍历key跟value值,推荐使用for (Map.Entry<String,String> entry : map.entrySet()) {System.out.println(entry.getKey()+";"+entry.getValue());}//只遍历key值for (String key : map.keySet()) {System.out.println(key);}//只遍历value值for (String value : map.values()) {System.out.println(value);}//通过遍历key值获取value值,效率最低,不推荐使用for (String key : map.keySet()) {String value = map.get(key);System.out.println(key+";"+value);}//jdk8 map.forEach方法List<String> list = new ArrayList<String>(map.size());map.forEach((key,value) -> {list.add(value);});System.out.println(list);}