java.util.WeakHashMap.containsKey() 方法

package com.codingdict;

import java.util.Map;
import java.util.WeakHashMap;

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

      Map<String, String> weakHashMap = new WeakHashMap<String, String>();

      // put keys and values in the Map      
      weakHashMap.put("1", "first");
      weakHashMap.put("2", "two");
      weakHashMap.put("3", "three");

      // check key value
      System.out.println("Checking value for key 1");
      System.out.println(weakHashMap.containsKey("1"));
   }    
}