带有字节数组键和字符串值的HashMap - containsKey（）函数不起作用

问题描述

我正在使用HashMap：byte []键和String值。但我意识到，即使我把相同的对象（相同的字节数组和相同的字符串值）通过使用

   > byte [] （或任何数组）不能作为 HashMap 中的键正常工作，因为数组不会覆盖 equals ，所以两个数组只有在引用同一个对象时才会被认为是相等的。
 
 
 
  byte [] 在一些自定义类中覆盖 hashCode 和等于，并将该自定义类用作HashMap的关键字。
 
I'm using a HashMap: byte[] key and String value. But I realize that even I put the same object (same byte array and same string value) by using
myList.put(TheSameByteArray, TheSameStringValue)
into HashMap, the table still inserts a new object with different HashMapEntry. Then function containsKey() cannot work.
Can someone explains this for me? How can I fix this? Thanks. (Android Java)
@Override public boolean containsKey(Object key) {
    if (key == null) {
        return entryForNullKey != null;
    }

    int hash = Collections.secondaryHash(key);
    HashMapEntry<K, V>[] tab = table;
    for (HashMapEntry<K, V> e = tab[hash & (tab.length - 1)];
            e != null; e = e.next) {
        K eKey = e.key;
        if (eKey == key || (e.hash == hash && key.equals(eKey))) {
            return true;
        }
    }
    return false;
}
 解决方案 
A byte[] (or any array) can't work properly as a key in a HashMap, since arrays don't override equals, so two arrays will be considered equal only if they refer to the same object.
You'll have to wrap your byte[] in some custom class that overrides hashCode and equals, and use that custom class as the key to your HashMap.
                        
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