map的keySet演示

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

public class map {
	public static void main(String[] args){
		Map<Integer,String> map = new HashMap<Integer,String>();
		method_2(map);
	}
	
	public static void method_2(Map<Integer,String> map){
		map.put(3, "xiaoming");
		map.put(8, "xiaoqiang");
		map.put(5, "dazhang");
		map.put(9, "wuming");
		
		Set<Integer> keySet = map.keySet();
		Iterator<Integer> it = keySet.iterator();
		
		while(it.hasNext()){
			Integer key = it.next();
			String value = map.get(key);
			System.out.println(key+":"+value);
		}
	}
}

3:xiaoming

5:dazhang

8:xiaoqiang

9:wuming