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");  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"); 

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

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());  }  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()); } 

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);  }  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); } 

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);           }