Map集合的遍历方法

import java.util.Collection;
import java.util.HashMap;
import java.util.Iterator;
import java.util.Map;
import java.util.Set;

public class TestC{
	
      public static void main(String[] args) {
            Map map = new HashMap();
            map.put(1, 123);
            map.put(2, 187);
            map.put(3, 44);
            System.out.println(map);
      
            //遍历所有的key集：keySet()
            Set keySet = map.keySet();
      
            Iterator iterator = keySet.iterator(); 
	    while(iterator.hasNext()){
		  System.out.println(iterator.next());
	    }
       
            //遍历所有的value集：values()
            Collection values = map.values();

            for(Object obj: values){
    	        System.out.println(obj);
            }

            //遍历所有的key-value
            Set set = map.keySet();
            Iterator iterator1 = set.iterator(); 
	    while(iterator1.hasNext()){
		  Object key = iterator1.next();
		  Object value = map.get(key);
		  System.out.print("["+key+","+value+"]"+",");
	    }
 
      }
}

运行结果：

{1=123, 2=187, 3=44}
1
2
3
123
187
44
[1,123],[2,187],[3,44],