原理解释文章：https://blog.csdn.net/beiyetengqing/article/details/7856113
代码应用：
wordTrie.txt(工具类)：

package com.xq.algorithm;import java.util.ArrayList;
import java.util.List;/*** * <p>Title:</p>* <p>Description: 单词Trie树* </p>* @createDate：2013-10-17* @author xq* @version 1.0*/
public class WordTrie {/**trie树根*/private TrieNode root = new TrieNode();/**英文字符串正则匹配*/static String  englishPattern="^[A-Za-z]+$";/**中文正则匹配*/static String chinesePattern="[\u4e00-\u9fa5]";static int ARRAY_LENGTH=26;static String zeroString="";/*** * @Title: addWord* @Description: add word* @param @param word    * @return void   * @throws*/public void addWord(String word) {if(word==null || "".equals(word.trim())){throw new IllegalArgumentException("word can not be null!");}if(!word.matches(englishPattern)){throw new IllegalArgumentException("word must be english!");}addWord(root, word);}/*** * @Title: addWord* @Description:add word to node* @param @param node* @param @param word    * @return void   * @throws*/private void addWord(TrieNode node, String word) {if (word.length() == 0) { // if all characters of the word has been// addednode.count++;node.nodeState=1;} else {node.prefixCount++;char c = word.charAt(0);c = Character.toLowerCase(c);int index = c - 'a';if(index>=0 && index<ARRAY_LENGTH){if (node.next[index] == null) { node.next[index] = new TrieNode();}// go the the next characteraddWord(node.next[index], word.substring(1));}}}/*** * @Title: prefixSearchWord* @Description: 前缀搜索* @param @param word* @param @return    * @return List<String>   * @throws*/public List<String> prefixSearchWord(String word){if(word==null || "".equals(word.trim())){return new ArrayList<String>();}if(!word.matches(englishPattern)){return new ArrayList<String>();}char c = word.charAt(0);c = Character.toLowerCase(c);int index = c - 'a';if(root.next!=null && root.next[index]!=null){return depthSearch(root.next[index],new ArrayList<String>(),word.substring(1),""+c,word);}else{return new ArrayList<String>();}}/*** * @Title: searchWord* @Description: 搜索单词,以a-z为根,分别向下递归搜索* @param @param word* @param @return    * @return List<String>   * @throws*/public List<String> searchWord(String word){if(word==null || "".equals(word.trim())){return new ArrayList<String>();}if(!word.matches(englishPattern)){return new ArrayList<String>();}char c = word.charAt(0);c = Character.toLowerCase(c);int index = c - 'a';List<String> list=new ArrayList<String>();if(root.next==null){return list;}for(int i=0;i<ARRAY_LENGTH;i++){int j='a'+i;char temp=(char)j;if(root.next[i]!=null){if(index==i){fullSearch(root.next[i],list,word.substring(1),""+temp,word);}else{fullSearch(root.next[i],list,word,""+temp,word);}}}return list;}/*** * @Title: fullSearch* @Description: 匹配到对应的字母,则以该字母为字根,继续匹配完所有的单词。* @param @param node* @param @param list 保存搜索到的字符串* @param @param word 搜索的单词.匹配到第一个则减去一个第一个,连续匹配,直到word为空串.若没有连续匹配,则恢复到原串。* @param @param matchedWord 匹配到的单词* @param @return    * @return List<String>   * @throws*/private List<String> fullSearch(TrieNode node,List<String> list,String word,String matchedWord,String inputWord){if(node.nodeState==1  && word.length()==0){list.add(matchedWord);}if(word.length() != 0){char c = word.charAt(0);c = Character.toLowerCase(c);int index = c - 'a';for(int i=0;i<ARRAY_LENGTH;i++){if(node.next[i]!=null){int j='a'+i;char temp=(char)j;if(index==i){//连续匹配fullSearch(node.next[i], list, word.substring(1), matchedWord+temp,inputWord);}else{//未连续匹配,则重新匹配fullSearch(node.next[i], list, inputWord, matchedWord+temp,inputWord);}}}}else{if(node.prefixCount>0){for(int i=0;i<ARRAY_LENGTH;i++){if(node.next[i]!=null){int j='a'+i;char temp=(char)j;fullSearch(node.next[i], list, zeroString, matchedWord+temp,inputWord);}}}}return list;}/*** * @Title: depthSearch* @Description: 深度遍历子树* @param @param node* @param @param list 保存搜索到的字符串* @param @param word 搜索的单词.匹配到第一个则减去一个第一个,连续匹配,直到word为空串.若没有连续匹配,则恢复到原串。* @param @param matchedWord 匹配到的单词* @param @return    * @return List<String>   * @throws*/private List<String> depthSearch(TrieNode node,List<String> list,String word,String matchedWord,String inputWord){if(node.nodeState==1 && word.length()==0){list.add(matchedWord);}if(word.length() != 0){char c = word.charAt(0);c = Character.toLowerCase(c);int index = c - 'a';//继续完全匹配,直到word为空串,否则未找到if(node.next[index]!=null){depthSearch(node.next[index], list, word.substring(1), matchedWord+c,inputWord);}}else{if(node.prefixCount>0){//若匹配单词结束,但是trie中的单词并没有完全找到,需继续找到trie中的单词结束.//node.prefixCount>0表示trie中的单词还未结束for(int i=0;i<ARRAY_LENGTH;i++){if(node.next[i]!=null){int j='a'+i;char temp=(char)j;depthSearch(node.next[i], list, zeroString, matchedWord+temp,inputWord);}}}}return list;}class TrieNode {/*** trie tree word count*/int count=0;/*** trie tree prefix count*/int prefixCount=0;/*** 指向各个子树的指针,存储26个字母[a-z]*/TrieNode[] next=new TrieNode[26];/*** 当前TrieNode状态 ,默认 0 , 1表示从根节点到当前节点的路径表示一个词*/int nodeState = 0;TrieNode(){count=0;prefixCount=0;next=new TrieNode[26];nodeState = 0;}}
}

测试类：

package com.xq.algorithm;import java.util.List;public class WordTrieMain {public static void main(String[] args){test();}public static void test1(){WordTrie trie=new WordTrie();trie.addWord("ibiyzbi");System.out.println("----------------------------------------");List<String> words=trie.searchWord("bi");for(String s: words){System.out.println(s);}}public static void test(){WordTrie trie=new WordTrie();trie.addWord("abi");trie.addWord("ai");trie.addWord("aqi");trie.addWord("biiiyou");trie.addWord("dqdi");trie.addWord("ji");trie.addWord("li");trie.addWord("liqing");trie.addWord("liqq");trie.addWord("liqqq");trie.addWord("qi");trie.addWord("qibi");trie.addWord("i");trie.addWord("ibiyzbi");List<String> list=trie.prefixSearchWord("li");for(String s: list){System.out.println(s);}System.out.println("----------------------------------------");List<String> li=trie.searchWord("i");for(String s: li){System.out.println(s);}System.out.println("----------------------------------------");List<String> words=trie.searchWord("bi");for(String s: words){System.out.println(s);}System.out.println("----------------------------------------");List<String> lst=trie.searchWord("q");for(String s: lst){System.out.println(s);}}
}