Several methods of Java Traversal map sample code _java

Several methods of traversing map in Java

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"); 

The first type is used for loops

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 ()); 
} 

The second type uses iterations

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 ()); 
} 

Iterating with keyset ()

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); 
} 

Iterating with EntrySet ()

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);           
}  

 

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