尚學堂

import java.util.*;
public class TestMap {
  public static void main(String args[]) {
    Map m1 = new HashMap(); 
    Map m2 = new TreeMap();
    //m1.put("one",new Integer(1));<span style="white-space:pre">	</span>//爲什麼一定要放進去Integer對象呢？這是因爲Map接口規定，裏面存放的必須是成對的對象，以便放在棧空間裏
    m1.put("one", 1);<span style="white-space:pre">			</span>//但是在現在版本的JDK中可以這麼寫，這叫自動打包自動解包
    //m1.put("two",new Integer(2));
    m1.put("two", 2);
    //m1.put("three",new Integer(3));
    m1.put("three", 3);
    //m2.put("A",new Integer(1));
   	m2.put("A", 1);
    //m2.put("B",new Integer(2));
    m2.put("B", 2);
    System.out.println(m1.size());
    System.out.println(m1.containsKey("one"));
    System.out.println
        //(m2.containsValue(new Integer(1)));
        (m2.containsValue(1));
    if(m1.containsKey("two")) {
      //int i = ((Integer)m1.get("two")).intValue();
      int i = (Integer)m1.get("two");
      System.out.println(i);
    }
    Map m3 = new HashMap(m1);
    m3.putAll(m2);
    System.out.println(m3);
  }
}