Map.putAll用法

/**
 * @(#)Map_putAllTest.java
 *
 * Map_putAllTest application
 *
 * @author 
 * @version 1.00 2013/10/12
 */
 
import java.util.HashMap;
	public class Map_putAllTest {
		public static void main(String[] args){
		   //两个map具有不同的key
		   HashMap map1=new HashMap(); 
		   map1.put("1", "A"); 
		   HashMap map2 = new HashMap(); 
		   map2.put("2", "B"); 
		   map2.put("3", "C"); 
		   map1.putAll(map2); 
		   System.out.println(map1);
		   //两个map具有重复的key
		   HashMap map3=new HashMap(); 
		   map3.put("1", "A"); 
		   HashMap map4 = new HashMap(); 
		   map4.put("1", "B"); 
		   map4.put("3", "C"); 
		   map3.putAll(map4); 
		   System.out.println(map3);
			}
		

Output:

{3=C, 2=B, 1=A}
{3=C, 1=B}