143 lines
4.7 KiB
Java
143 lines
4.7 KiB
Java
/*
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* IK 中文分词 版本 8.4.0
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* IK Analyzer release 8.4.0
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*
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* Licensed to the Apache Software Foundation (ASF) under one or more
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* contributor license agreements. See the NOTICE file distributed with
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* this work for additional information regarding copyright ownership.
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* The ASF licenses this file to You under the Apache License, Version 2.0
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* (the "License"); you may not use this file except in compliance with
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* the License. You may obtain a copy of the License at
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*
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* http://www.apache.org/licenses/LICENSE-2.0
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*
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* Unless required by applicable law or agreed to in writing, software
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* distributed under the License is distributed on an "AS IS" BASIS,
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* WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
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* See the License for the specific language governing permissions and
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* limitations under the License.
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*
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* 源代码由林良益(linliangyi2005@gmail.com)提供
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* 版权声明 2012，乌龙茶工作室
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* provided by Linliangyi and copyright 2012 by Oolong studio
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*
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* 8.4.0版本 由 Magese (magese@live.cn) 更新
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* release 8.4.0 update by Magese(magese@live.cn)
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*
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*/
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package org.wltea.analyzer.query;
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import org.apache.lucene.analysis.standard.StandardAnalyzer;
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import org.apache.lucene.queryparser.classic.ParseException;
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import org.apache.lucene.queryparser.classic.QueryParser;
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import org.apache.lucene.search.Query;
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import org.wltea.analyzer.core.IKSegmenter;
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import org.wltea.analyzer.core.Lexeme;
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import java.io.IOException;
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import java.io.StringReader;
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import java.util.ArrayList;
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import java.util.List;
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/**
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* Single Word Multi Char Query Builder
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* IK分词算法专用
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*
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* @author linliangyi
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*/
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class SWMCQueryBuilder {
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/**
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* 生成SWMCQuery
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*
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* @return Lucene Query
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*/
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static Query create(String fieldName, String keywords) {
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if (fieldName == null || keywords == null) {
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throw new IllegalArgumentException("参数 fieldName 、 keywords 不能为null.");
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}
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//1.对keywords进行分词处理
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List<Lexeme> lexemes = doAnalyze(keywords);
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//2.根据分词结果，生成SWMCQuery
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return getSWMCQuery(fieldName, lexemes);
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}
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/**
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* 分词切分，并返回结链表
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*/
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private static List<Lexeme> doAnalyze(String keywords) {
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List<Lexeme> lexemes = new ArrayList<>();
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IKSegmenter ikSeg = new IKSegmenter(new StringReader(keywords), true);
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try {
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Lexeme l;
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while ((l = ikSeg.next()) != null) {
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lexemes.add(l);
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}
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} catch (IOException e) {
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e.printStackTrace();
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}
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return lexemes;
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}
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/**
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* 根据分词结果生成SWMC搜索
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*/
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private static Query getSWMCQuery(String fieldName, List<Lexeme> lexemes) {
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//构造SWMC的查询表达式
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StringBuilder keywordBuffer = new StringBuilder();
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//精简的SWMC的查询表达式
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StringBuilder keywordBuffer_Short = new StringBuilder();
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//记录最后词元长度
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int lastLexemeLength = 0;
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//记录最后词元结束位置
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int lastLexemeEnd = -1;
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int shortCount = 0;
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int totalCount = 0;
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for (Lexeme l : lexemes) {
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totalCount += l.getLength();
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//精简表达式
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if (l.getLength() > 1) {
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keywordBuffer_Short.append(' ').append(l.getLexemeText());
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shortCount += l.getLength();
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}
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if (lastLexemeLength == 0) {
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keywordBuffer.append(l.getLexemeText());
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} else if (lastLexemeLength == 1 && l.getLength() == 1
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&& lastLexemeEnd == l.getBeginPosition()) {//单字位置相邻，长度为一，合并)
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keywordBuffer.append(l.getLexemeText());
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} else {
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keywordBuffer.append(' ').append(l.getLexemeText());
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}
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lastLexemeLength = l.getLength();
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lastLexemeEnd = l.getEndPosition();
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}
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//借助lucene queryparser 生成SWMC Query
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QueryParser qp = new QueryParser(fieldName, new StandardAnalyzer());
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qp.setDefaultOperator(QueryParser.AND_OPERATOR);
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qp.setAutoGeneratePhraseQueries(true);
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if ((shortCount * 1.0f / totalCount) > 0.5f) {
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try {
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return qp.parse(keywordBuffer_Short.toString());
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} catch (ParseException e) {
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e.printStackTrace();
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}
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} else {
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if (keywordBuffer.length() > 0) {
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try {
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return qp.parse(keywordBuffer.toString());
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} catch (ParseException e) {
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e.printStackTrace();
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}
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}
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}
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return null;
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}
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}
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