java中遍历MAP的几种方法

快来打我* 2022-09-25 12:23 178阅读 0赞

java中遍历MAP的几种方法   
Java代码   
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");   
第一种用for循环   
Java代码   
  
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());   
\}   
  
第二种用迭代   
Java代码   
  
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());   
\}   
用keySet()迭代   
Java代码   
  
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);   
\}   
  
用entrySet()迭代   
Java代码   
  
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);                       
\}