import java.util.*;
public class TestHashtable {
   
    public static void main(String [] args){
        Hashtable numbers= new Hashtable();
        numbers.put(new MyKey("zhangsan",18),new Integer(1));
        numbers.put(new MyKey("lisi",19),new Integer(2));
        numbers.put(new MyKey("wangwu",20),new Integer(3));
        Enumeration e = numbers.keys();
        while(e.hasMoreElements()){
            MyKey key = (MyKey)e.nextElement();
            System.out.print(key + "=");
            System.out.println(numbers.get(key));
        }
         MyKey key1 = new MyKey("zhangsan",18);
         System.out.println(numbers.get( key1 ));
         MyKey key2 = (Hashtable)new MyKey("lisi",110);//为什么不能用这种转换呢
        
        System.out.println(numbers.get( key1 ));     //我理解成这样就不用在MyKey中写Hashcode方法了 因为 已经强制转换成Hashtable已经有这个方法
}
// -----------------------------------------------------------------
public class MyKey  {
    private String name = null;
    private int age = 0;
   
    public boolean equals(Object obj){
        if(obj instanceof MyKey){
            MyKey objTemp = (MyKey)obj;
            if(name.equals(objTemp.name) && age == objTemp.age){
                return true;
            }
            else{
                return false;
            }
        }
        else{
            return false;
        }
    }

    public int hashCode(){
        return name.hashCode() + age;
    }

    public MyKey(String s ,int i ){
        this.name = s;
        this.age = i;
    }
    public String toString(){
        return name + "XP" + age;
    }
}