package com.jbx.hash; import java.util.HashMap; import java.util.Hashtable; public class TestHashMap { public static void main(String[] args) { HashMap<String, String> hashMap = new HashMap<String,String>(); hashMap.put("null", "hashmap_key为什么可以为空字符串呢?"); hashMap.put(null, null); //是否包含null这个key true System.out.println(hashMap.containsKey(null)); //是否包含null这个value true System.out.println(hashMap.containsValue(null)); System.out.println(hashMap.get("null")); // System.out.println(hashMap.get(null)); Hashtable<String,String> hashtable2 = new Hashtable<String,String>(); hashtable2.put("null", "hashtable key为什么可以为空字符串呢?"); hashtable2.put("hj", "null"); System.out.println(hashtable2.containsValue("null"));//true System.out.println(hashtable2.contains("null"));//true System.out.println(hashtable2.containsKey("hj"));//true System.out.println(hashtable2.get("null")); System.out.println(hashtable2.get("hj")); } }
HASHMAP测试
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转载自lovemojienv.iteye.com/blog/2393976
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