遍历Map的几种方法

		Map<String,String> map=new HashMap<String,String>();
		map.put("username", "qq");
		map.put("passWord", "123");
		map.put("userID", "1");
		map.put("email", "qq@qq.com");

 第一种用for循环

		for(Map.Entry<String, String> entry:map.entrySet())
		{
			System.out.println(entry.getKey()+"--->"+entry.getValue());
		}

  第二种用迭代

Set set = map.entrySet();     
        Iterator i = set.iterator();     
        while(i.hasNext()){  
        	 Map.Entry<String, String> entry1=(Map.Entry<String, String>)i.next();
        	 
               
              System.out.println(entry1.getKey()+"=="+entry1.getValue());
        }

 用keySet()迭代

Iterator it=map.keySet().iterator();
		while(it.hasNext())
		{
			String key;
			String value;
			key=it.next().toString();
			value=map.get(key);
			System.out.println(key+"--"+value);
		}

用entrySet()迭代

Iterator it=map.entrySet().iterator();    
		  System.out.println( map.entrySet().size());
		String key;    
		   
		String value;    
		   
		while(it.hasNext()){    
		   
		    Map.Entry entry = (Map.Entry)it.next();    
		   
		    key=entry.getKey().toString();    
		   
		    value=entry.getValue().toString();    
		   
		    System.out.println(key+"===="+value);    
		   
		}