Map集合

package test4;

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

public class test13 {

	public static void main(String[] args) {
		// TODO Auto-generated method stub
    //method();
		Map<Integer,String> map =new HashMap<Integer,String>();
		method(map);
	}

	private static void method(Map<Integer,String> map) {
		// TODO Auto-generated method stub
		System.out.println(map.put(1, "a1"));
		System.out.println(map.put(2, "a2"));
		map.put(2, "b2");
		map.put(2, "c2");
		//map.remove(1);
		System.out.println(map.get(2));
		System.out.println(map.containsKey(2)+""+map.containsValue("c2")+""+map.isEmpty());
		System.out.println(map);
		System.out.println(map.size());
		Set<Integer> keySet = map.keySet();
		Iterator<Integer> it =  keySet.iterator();
		
		while(it.hasNext()){
			Integer i = it.next();
			System.out.println(i);
		}
		   Set<Map.Entry<Integer,String>> entrySet = map.entrySet();
		   Iterator<Map.Entry<Integer,String>> it2 =   entrySet.iterator();
	     while(it2.hasNext()){
		   Map.Entry<Integer, String> me =it2.next();
		   Integer i = me.getKey();
		   String s = me.getValue();
		   System.out.println(i+" : "+s);
	   }
	     Collection<String> str =  map.values();
	     Iterator<String>   it3 =     str.iterator();
	     while(it3.hasNext()){
	    	 System.out.println( it3.next() );
	     }
	}

}