在hashmap中将字符串与keyvalue进行比较时忽略大小写

Question

我试图检查我的hashmap键集是否包含字符串'buffSB.toString()'.但我想比较忽略的情况(上部或下部).

static StringBuilder buffSB = new StringBuilder(); 

buffSB.append(alphabet);

Map<String, String> pref =  new Datamatch().main();  // Getting the Hashmap from other class

if(pref.containsKey(buffSB.toString()))             //This is where I need to ignore case while searching string in the map key set 
  { 
      String val = pref.get(buffSB.toString());
  }

任何帮助将不胜感激!!!

Answer 1

如果您看到 HashMap getKey 方法的实现，您必须传递正确的键来生成哈希值并从该存储桶中获取实际值。

    if (key == null)
        return getForNullKey();
    int hash = hash(key.hashCode());
    for (Entry<K,V> e = table[indexFor(hash, table.length)];
         e != null;
         e = e.next) {
        Object k;
        if (e.hash == hash && ((k = e.key) == key || key.equals(k)))
            return e.value;
    }
    return null;

三种解决方案

    Map<String, String> pref = new TreeMap<String, String>(String.CASE_INSENSITIVE_ORDER);

或者

    Map<String, String> map = new CaseInsensitiveMap<String, String>();

或者

    Looping through map with the ignore case