过滤黑名单

最近公司需要个过滤黑名单的程序，到javaeye上看了下，大家搞的太难了，看不大懂，就写了个简单的。
一个树，每个节点有个hashmap,一个iskeyword,通过isKeyWord来判断是否关键字，如果不是通过hashmap向下找寻,如果hashmap找不到,从root节点重新找
import java.util.*;



public class Trie {
   
    private Vertex root;
   
    public static void main(String[] args){
    Trie t = new Trie();
    t.addWord("中");
    t.addWord("中华");
    t.addWord("中华人");
    t.addWord("胡");
    System.out.println(t.isExistWords("啊uhfgdigdfg时发生大幅度上升的方式的答复 "));
    System.out.println(t.isExistWords("中啊uhfgdigdfg时发生大幅度上升的方式的答复 "));
    System.out.println(t.isExistWords("胡啊uhfgdigdfg时发生大幅度上升的方式的答复 "));
    }
   
   
    protected class Vertex {
    protected String value;
        protected boolean isKeyWord;
        protected Map edges;

        Vertex(String value,boolean inital) {
        isKeyWord = false;
            this.value = value;
            if(inital) edges = new HashMap();
        }
       
    }
   
    public Trie () {
        root = new Vertex("root",true);
    }

   
    public boolean isExistWords(String word) {
        return isExistWords(root, word);
    }   
    private boolean isExistWords(Vertex vertex, String wordSegment) {
    if(vertex.isKeyWord) return true;
    if (wordSegment.length() == 0) {
    if(!vertex.isKeyWord)
    return false;
    }
        char c = wordSegment.charAt(0);
        Vertex v = (Vertex) vertex.edges.get(String.valueOf(c));
        if (v == null) {
            return isExistWords(root, wordSegment.substring(1));
        } else {
            return isExistWords(v, wordSegment.substring(1));
        }       
    }
   
    public void addWord(String word) {
        addWord(root, word);
    }
   
    private void addWord(Vertex vertex, String word) {
    if (word.length() != 0) {
            char c = word.charAt(0);
            Vertex v = new Vertex(String.valueOf(c),false);
            if (!vertex.edges.keySet().contains(String.valueOf(c))) {
            v.edges = new HashMap();
                vertex.edges.put(String.valueOf(c), v);
            }else{
            v = (Vertex) vertex.edges.get(String.valueOf(c));
            }
            addWord(v, word.substring(1));
        }else{
        vertex.isKeyWord = true;
        }
    }
     

}