java中遍历MAP的几种方法

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);                     
}   

 

上述是转载网址： http://rain-2372.iteye.com/blog/1615615

 

下述代码是自己增加：

 

System.out.println("==================================================");

// 定义Map 
Map<String, Object> mapTestValue1 = new HashMap<String , Object>();
Map<String, Object> mapTestValue2 = new HashMap<String , Object>();
Map<String, Object> mapTestValue3 = new HashMap<String , Object>();

mapTestValue1.put("111", "1111");
mapTestValue2.put("222", "2222");
mapTestValue3.put("333", "3333");

// 定义Map 嵌套Map<String , Object> 对象

// 第一种定义方式
Map<String , Map<String, Object>> mapObject = FastMap.newInstance();
// 第二种定义方式
Map<String , Map<String, Object>> mapObject2 = new HashMap<String, Map<String, Object>>() ;

// 将Map 作为Value 加载到Map对象中
mapObject.put("11", mapTestValue1);
mapObject.put("22", mapTestValue2);
mapObject.put("33", mapTestValue3);

// 遍历map数据 使用Set格式进行接收
Set<Entry<String, Map<String, Object>>> setMap = mapObject.entrySet();

for (Entry<String , Map<String , Object>> setEntry : setMap) {
String key = setEntry.getKey() ;
System.out.println("setEntry.getKey() : " + setEntry.getKey() + " , setEntry.getValue() : " + setEntry.getValue() );

Map<String , Object> mapKeyValue = setEntry.getValue() ;
// System.out.println("mapKeyValue.getKey() : " + mapKeyValue. + " , mapKeyValue.getValue() : " + mapKeyValue.getValue() );
System.out.println("111 : " + mapKeyValue.get("111"));
System.out.println("222 : " + mapKeyValue.get("222"));
System.out.println("333 : " + mapKeyValue.get("333"));
}