java.util.Hashtable.containsKey()方法

package com.codingdict;

import java.util.*;

public class HashTableDemo {
   public static void main(String args[]) {

      // create hash table
      Hashtable htable = new Hashtable();

      // put values into the table
      htable.put(1, "A");
      htable.put(2, "B");
      htable.put(3, "C");
      htable.put(4, "D");

      // check if table contains key "3"
      boolean isavailable = htable.containsKey(3);

      // display search result
      System.out.println("Hash table contains key '3': "+isavailable);      
   }    
}