public class HashMap<K,V> extends AbstractMap<K,V> implements Map<K,V>, Cloneable, Serializable

public class TreeMap<K,V>
??? extends AbstractMap<K,V>
??? implements SortedMap<K,V>, Cloneable, java.io.Serializable

Obviously,TreeMap store elements sorted.But for the chinese word ,the default Comparator don't? do it rightly,so you must write your Comparator .this is an example from web:

importjava.text.CollationKey;

import java.text.Collator;

import java.util.Comparator;

?

/**

?*@author www.inspiresky.com

?*

?*/

publicclass CollatorComparator implements Comparator {

Collator collator = Collator.getInstance();

?

publicint compare(Object element1, Object element2) {

??? CollationKey key1 = collator.getCollationKey(element1.toString());

??? CollationKey key2 = collator.getCollationKey(element2.toString());

??? return key1.compareTo(key2);

}

}

? to use this CollatorComparator ,use TreeMap constructor
Mothod :

?public TreeMap(Comparator<? super K> c) {
??????? this.comparator = c;
??? }