ictclas4j for lucene analyzer,
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原文出处：http://blog.chenlb.com/2009/01/ictclas4j-for-lucene-analyzer.html
在 lucene 的中文分词域里，有好几个分词选择，有：je、paoding、IK。最近想把 ictclas 拿来做 lucene 的中文分词。网上看了下资料，觉得 ictclas4j 是比较好的选择，作者博客相关文章：http://blog.csdn.net/sinboy/category/207165.aspx 。ictclas4j 目前是0.9.1版，项目地址：http://code.google.com/p/ictclas4j/ ，下载地址：http://ictclas4j.googlecode.com/files/ictclas4j_0.9.1.rar 。
下载 ictclas4j 看了下源码，正找示例，org.ictclas4j.run.SegMain 可以运行。分词的核心逻辑在org.ictclas4j.segment.Segment 的 split(String src) 方法中。运行 SegMain 的结果是一串字符串（带有词性标注），细看了 Segment 与 org.ictclas4j.bean.SegResult 没看到一个个分好的词。这样就比较难以扩展成为 lucene 的分词器。555，接下还是 hack 一下。
hack 的突破口的它的最终结果，在 SegResult 类里的 finalResult 字段记录。 在Segment.split(String src) 生成。慢慢看代码找到 outputResult(ArrayList
1、修改 Segment：
1)把原来的outputResult(ArrayList
// 根据分词路径生成分词结果
private String outputResult(ArrayList wrList, ArrayList words) {
String result = null;
String temp=null;
char[] pos = new char[2];
if (wrList != null && wrList.size() > 0) {
result = "";
for (int i = 0; i < wrList.size(); i++) {
SegNode sn = wrList.get(i);
if (sn.getPos() != POSTag.SEN_BEGIN && sn.getPos() != POSTag.SEN_END) {
int tag = Math.abs(sn.getPos());
pos[0] = (char) (tag / 256);
pos[1] = (char) (tag % 256);
temp=""+pos[0];
if(pos[1]>0)
temp+=""+pos[1];
result += sn.getSrcWord() + "/" + temp + " ";
if(words != null) { //chenlb add
words.add(sn.getSrcWord());
}
}
}
}
return result;
}
2)原来的outputResult(ArrayList
//chenlb move to outputResult(ArrayList wrList, ArrayList words)
private String outputResult(ArrayList wrList) {
return outputResult(wrList, null);
}
3)修改调用outputResult(ArrayList
public SegResult split(String src) {
SegResult sr = new SegResult(src);// 分词结果
String finalResult = null;
if (src != null) {
finalResult = "";
int index = 0;
String midResult = null;
sr.setRawContent(src);
SentenceSeg ss = new SentenceSeg(src);
ArrayList sens = ss.getSens();
ArrayList words = new ArrayList(); //chenlb add
for (Sentence sen : sens) {
logger.debug(sen);
long start=System.currentTimeMillis();
MidResult mr = new MidResult();
mr.setIndex(index++);
mr.setSource(sen.getContent());
if (sen.isSeg()) {
// 原子分词
AtomSeg as = new AtomSeg(sen.getContent());
ArrayList atoms = as.getAtoms();
mr.setAtoms(atoms);
System.err.println("[atom time]:"+(System.currentTimeMillis()-start));
start=System.currentTimeMillis();
// 生成分词图表,先进行初步分词，然后进行优化，最后进行词性标记
SegGraph segGraph = GraphGenerate.generate(atoms, coreDict);
mr.setSegGraph(segGraph.getSnList());
// 生成二叉分词图表
SegGraph biSegGraph = GraphGenerate.biGenerate(segGraph, coreDict, bigramDict);
mr.setBiSegGraph(biSegGraph.getSnList());
System.err.println("[graph time]:"+(System.currentTimeMillis()-start));
start=System.currentTimeMillis();
// 求N最短路径
NShortPath nsp = new NShortPath(biSegGraph, segPathCount);
ArrayList> bipath = nsp.getPaths();
mr.setBipath(bipath);
System.err.println("[NSP time]:"+(System.currentTimeMillis()-start));
start=System.currentTimeMillis();
for (ArrayList onePath : bipath) {
// 得到初次分词路径
ArrayList segPath = getSegPath(segGraph, onePath);
ArrayList firstPath = AdjustSeg.firstAdjust(segPath);
String firstResult = outputResult(firstPath);
mr.addFirstResult(firstResult);
System.err.println("[first time]:"+(System.currentTimeMillis()-start));
start=System.currentTimeMillis();
// 处理未登陆词，进对初次分词结果进行优化
SegGraph optSegGraph = new SegGraph(firstPath);
ArrayList sns = clone(firstPath);
personTagger.recognition(optSegGraph, sns);
transPersonTagger.recognition(optSegGraph, sns);
placeTagger.recognition(optSegGraph, sns);
mr.setOptSegGraph(optSegGraph.getSnList());
System.err.println("[unknown time]:"+(System.currentTimeMillis()-start));
start=System.currentTimeMillis();
// 根据优化后的结果，重新进行生成二叉分词图表
SegGraph optBiSegGraph = GraphGenerate.biGenerate(optSegGraph, coreDict, bigramDict);
mr.setOptBiSegGraph(optBiSegGraph.getSnList());
// 重新求取N－最短路径
NShortPath optNsp = new NShortPath(optBiSegGraph, segPathCount);
ArrayList> optBipath = optNsp.getPaths();
mr.setOptBipath(optBipath);
// 生成优化后的分词结果，并对结果进行词性标记和最后的优化调整处理
ArrayList adjResult = null;
for (ArrayList optOnePath : optBipath) {
ArrayList optSegPath = getSegPath(optSegGraph, optOnePath);
lexTagger.recognition(optSegPath);
String optResult = outputResult(optSegPath, words); //chenlb changed
mr.addOptResult(optResult);
adjResult = AdjustSeg.finaAdjust(optSegPath, personTagger, placeTagger);
String adjrs = outputResult(adjResult);
System.err.println("[last time]:"+(System.currentTimeMillis()-start));
start=System.currentTimeMillis();
if (midResult == null)
midResult = adjrs;
break;
}
}
sr.addMidResult(mr);
} else {
midResult = sen.getContent();
words.add(midResult); //chenlb add
}
finalResult += midResult;
midResult = null;
}
sr.setWords(words); //chenlb add
sr.setFinalResult(finalResult);
DebugUtil.output2html(sr);
logger.info(finalResult);
}
return sr;
}
4)Segment中的构造方法，词典路径分隔可以改为"/"
5)同时修改了一个漏词的 bug，请看：ictclas4j的一个bug
2、修改 SegResult：
添加以下内容：
private ArrayList words; //记录分词后的词结果，chenlb add
/**
* 添加词条。
* @param word null 不添加
* @author chenlb 2009-1-21 下午05:01:25
*/
public void addWord(String word) {
if(words == null) {
words = new ArrayList();
}
if(word != null) {
words.add(word);
}
}
public ArrayList getWords() {
return words;
}
public void setWords(ArrayList words) {
this.words = words;
}
下面是创建 ictclas4j 的 lucene analyzer
1、新建一个ICTCLAS4jTokenizer类：
package com.chenlb.analysis.ictclas4j;
import java.io.IOException;
import java.io.Reader;
import java.util.ArrayList;
import org.apache.lucene.analysis.Token;
import org.apache.lucene.analysis.Tokenizer;
import org.ictclas4j.bean.SegResult;
import org.ictclas4j.segment.Segment;
/**
* ictclas4j 切词
*
* @author chenlb 2009-1-23 上午11:39:10
*/
public class ICTCLAS4jTokenizer extends Tokenizer {
private static Segment segment;
private StringBuilder sb = new StringBuilder();
private ArrayList words;
private int startOffest = 0;
private int length = 0;
private int wordIdx = 0;
public ICTCLAS4jTokenizer() {
words = new ArrayList();
}
public ICTCLAS4jTokenizer(Reader input) {
super(input);
char[] buf = new char[8192];
int d = -1;
try {
while((d=input.read(buf)) != -1) {
sb.append(buf, 0, d);
}
} catch (IOException e) {
e.printStackTrace();
}
SegResult sr = seg().split(sb.toString()); //分词
words = sr.getWords();
}
public Token next(Token reusableToken) throws IOException {
assert reusableToken != null;
length = 0;
Token token = null;
if(wordIdx < words.size()) {
String word = words.get(wordIdx);
length = word.length();
token = reusableToken.reinit(word, startOffest, startOffest+length);
wordIdx++;
startOffest += length;
}
return token;
}
private static Segment seg() {
if(segment == null) {
segment = new Segment(1);
}
return segment;
}
}
2、新建一个ICTCLAS4jFilter类：
package com.chenlb.analysis.ictclas4j;
import org.apache.lucene.analysis.Token;
import org.apache.lucene.analysis.TokenFilter;
import org.apache.lucene.analysis.TokenStream;
/**
* 标点符等， 过虑.
*
* @author chenlb 2009-1-23 下午03:06:00
*/
public class ICTCLAS4jFilter extends TokenFilter {
protected ICTCLAS4jFilter(TokenStream input) {
super(input);
}
public final Token next(final Token reusableToken) throws java.io.IOException {
assert reusableToken != null;
for (Token nextToken = input.next(reusableToken); nextToken != null; nextToken = input.next(reusableToken)) {
String text = nextToken.term();
switch (Character.getType(text.charAt(0))) {
case Character.LOWERCASE_LETTER:
case Character.UPPERCASE_LETTER:
// English word/token should larger than 1 character.
if (text.length()>1) {
return nextToken;
}
break;
case Character.DECIMAL_DIGIT_NUMBER:
case Character.OTHER_LETTER:
// One Chinese character as one Chinese word.
// Chinese word extraction to be added later here.
return nextToken;
}
}
return null;
}
}
3、新建一个ICTCLAS4jAnalyzer类：
package com.chenlb.analysis.ictclas4j;
import java.io.Reader;
import org.apache.lucene.analysis.Analyzer;
import org.apache.lucene.analysis.LowerCaseFilter;
import org.apache.lucene.analysis.StopFilter;
import org.apache.lucene.analysis.TokenStream;
/**
* ictclas4j 的 lucene 分析器
*
* @author chenlb 2009-1-23 上午11:39:39
*/
public class ICTCLAS4jAnalyzer extends Analyzer {
private static final long serialVersionUID = 1L;
// 可以自定义添加更多的过虑的词（高频无多太用处的词）
private static final String[] STOP_WORDS = {
"and", "are", "as", "at", "be", "but", "by",
"for", "if", "in", "into", "is", "it",
"no", "not", "of", "on", "or", "such",
"that", "the", "their", "then", "there", "these",
"they", "this", "to", "was", "will", "with",
"的"
};
public TokenStream tokenStream(String fieldName, Reader reader) {
TokenStream result = new ICTCLAS4jTokenizer(reader);
result = new ICTCLAS4jFilter(new StopFilter(new LowerCaseFilter(result), STOP_WORDS));
return result;
}
}
下面来测试下分词效果：
文本内容：
京华时报1月23日报道 昨天，受一股来自中西伯利亚的强冷空气影响，本市出现大风降温天气，白天最高气温只有零下7摄氏度，同时伴有6到7级的偏北风。
原分词结果：
京华/nz 时/ng 报/v 1月/t 23日/t 报道/v 昨天/t ，/w 受/v 一/m 股/q 来自/v 中/f 西伯利亚/ns 的/u 强/a 冷空气/n 影响/vn ，/w 本市/r 出现/v 大风/n 降温/vn 天气/n ，/w 白天/t 最高/a 气温/n 只/d 有/v 零下/s 7/m 摄氏度/q ，/w 同时/c 伴/v 有/v 6/m 到/v 7/m 级/q 的/u 偏/a 北风/n 。/w
analyzer：
[京华] [时] [报] [1月] [23日] [报道] [昨天] [受] [一] [股] [来自] [中] [西伯利亚] [强] [冷空气] [影响] [本市] [出现] [大风] [降温] [天气] [白天] [最高] [气温] [只] [有] [零下] [7] [摄氏度] [同时] [伴] [有] [6] [到] [7] [级] [偏] [北风]
我改过的源码可以下载：ictclas4j-091-for-lucene-src
依赖的jar：commons-lang-2.1.jar,log4j-1.2.12.jar,lucene-core-2.4.jar