Java map 优雅的元素遍历方式说明

public static void main(String[] args) {
    // map init
    Map<String, String> map = new HashMap<>();
    map.put("k", "v");
 
    /*=====处理函数只有单条语句=====*/
    map.forEach((k, v) -> System.out.println(k + v));
 
    /*=====处理函数有多个步骤=======*/
    map.forEach((k, v) -> {
      System.out.println(111);
      System.out.println(k + v);
    });
  }

public static void main(String[] args) {
//		Map<String, Object> map = new HashMap<String, Object>();
		Map<String, Object> map = new LinkedHashMap<String, Object>();
		map.put("username","zhaokuo");
		map.put("password", "123456");
		map.put("email", "zhaokuo719@163.com");
		map.put("sex", "男");
		
		//第一种 用for循环的方式
		for (Map.Entry<String, Object> m :map.entrySet()) {
			System.out.println(m.getKey()+"\t"+m.getValue());
		}
		
		//利用迭代 （Iterator）
		Set set=map.entrySet();
		Iterator iterator=set.iterator();
		while(iterator.hasNext()){
				Map.Entry<String, Object> enter=(Entry<String, Object>) iterator.next();
				System.out.println(enter.getKey()+"\t"+enter.getValue());
		}
		//利用KeySet 迭代
		Iterator it = map.keySet().iterator();
		while(it.hasNext()){
			 String key;  
		   String value;  
		   key=it.next().toString();  
		   value=(String) map.get(key);  
		   System.out.println(key+"--"+value);  
		}
		//利用EnterySet迭代
		Iterator i=map.entrySet().iterator();     
		System.out.println( map.entrySet().size());  
		String key;     
		String value;  
		while(i.hasNext()){  
		    Map.Entry entry = (Map.Entry)i.next();     
		    key=entry.getKey().toString();     
		    value=entry.getValue().toString();     
		    System.out.println(key+"===="+value);          
		} 
		
		System.out.println(getKeyByValue(map, "zhaokuo"));
	}

//根据Value取Key
	public static String getKeyByValue(Map map, Object value) {
		String keys="";
		Iterator it = map.entrySet().iterator();
		while (it.hasNext()) {
			Map.Entry entry = (Entry) it.next();
			Object obj = entry.getValue();
			if (obj != null && obj.equals(value)) {
				keys=(String) entry.getKey();
			}
 
 
		}
		return keys;
		}