@Override
	protected Object customKey(Object key) {
		if (null != key && key instanceof CharSequence) {
			key = key.toString().toLowerCase();
		}
		return key;
	}
@ Override protected Object customKey ( Object key ) { if ( null != key && key instanceof CharSequence ) { key = key . toString ( ) . toLowerCase ( ) ; } return key ; }
将Key转为小写

@param key KEY
@return 小写KEY