import java.util.*;public class HashTableDemo{    public static void main(String[] args)    {        Hashtable numbers = new Hashtable();        numbers.put("one",new Integer(1));        numbers.put("two",new Integer(2));        numbers.put("three",new Integer(3));        Integer n = (Integer)numbers.get("two");        if(n != null)        {            System.out.println("two = " +n);        }    }}

运行结果：

two = 2