Java 集合 hashmap内容复制

import java.util.HashMap;
class HashMapDemo{ 
  public static void main(String[] args) {
     // Create a HashMap
     HashMap<Integer, String> hmap = new HashMap<Integer, String>();

     //add elements to HashMap
     hmap.put(1, "AA");
     hmap.put(2, "BB");
     hmap.put(3, "CC");
     hmap.put(4, "DD");

     // Create another HashMap
     HashMap<Integer, String> hmap2 = new HashMap<Integer, String>();

     // Adding elements to the recently created HashMap
     hmap2.put(11, "Hello");
     hmap2.put(22, "Hi");

     // Copying one HashMap "hmap" to another HashMap "hmap2"
     hmap2.putAll(hmap);

     // Displaying HashMap "hmap2" content
     System.out.println("HashMap 2 contains: "+ hmap2);
  }
}

HashMap 2 contains: {1=AA, 2=BB, 3=CC, 4=DD, 22=Hi, 11=Hello}