Luence入门

ゞ浴缸里的玫瑰 2022-01-29 07:29 229阅读 0赞

# 前言 #

全文检索是比较常见的一种查询方式，在互联网行业更为常见。以luence为入门点，进行学习。这篇博客只是个人的学习笔记，不正确的地方希望指出。

# luence检索的思路简单总结 #

![在这里插入图片描述][watermark_type_ZmFuZ3poZW5naGVpdGk_shadow_10_text_aHR0cHM6Ly9ibG9nLmNzZG4ubmV0L0FMZWFycnJpbmc_size_16_color_FFFFFF_t_70]

# 开发代码 #

package com;
    
    import org.apache.lucene.analysis.standard.StandardAnalyzer;
    import org.apache.lucene.document.Document;
    import org.apache.lucene.document.Field;
    import org.apache.lucene.index.IndexWriter;
    import org.apache.lucene.queryParser.MultiFieldQueryParser;
    import org.apache.lucene.queryParser.QueryParser;
    import org.apache.lucene.search.*;
    import org.junit.Test;
    
    import java.io.BufferedReader;
    import java.io.File;
    import java.io.FileReader;
    
    /**
     * @author lf
     * @Title: LuenceTest
     * @Description: TODO
     * @date 2019/5/21 11:13
     */
    public class LuenceTest {
    
        String indexPath = "D:\\pyg_work\\project\\my-test\\src\\main\\resources\\luenceIndexFile";//索引库位置(文件夹)
        StandardAnalyzer standardAnalyzer = new StandardAnalyzer();//分词器
        String filePath = "D:\\pyg_work\\project\\my-test\\src\\main\\resources\\myWorlds.txt";//资源文件位置
        /**
         * 　　* @Description: 采集文档，创建索引库
         * 　　* @date 2019/5/21 11:13
         *
         */
        @Test
        public void createIndex() throws Exception {
            //1.file -->doc（采集资源数据）
            File file = new File(filePath);
            Document doc = new Document();
            doc.add(new Field("name",file.getName(),Field.Store.YES, Field.Index.ANALYZED));//Field.Index.ANALYZED 建立索引，对该字段分词
            doc.add(new Field("content",readFile(file),Field.Store.YES, Field.Index.ANALYZED));
            doc.add(new Field("size",file.length()+"",Field.Store.YES, Field.Index.NOT_ANALYZED));//Field.Index.NOT_ANALYZED 建立索引，但是不对该字段分词
            doc.add(new Field("path",file.getAbsolutePath(),Field.Store.YES, Field.Index.NO));//Field.Index.NO 不建立索引
    
            //2.建立索引 indexWriter 维护索引库的对象（对document对象进行增删改）
            boolean createIndex = true; //是否重新创建索引库
            IndexWriter indexWriter = new IndexWriter(indexPath, standardAnalyzer, createIndex, IndexWriter.MaxFieldLength.UNLIMITED);//IndexWriter.MaxFieldLength.UNLIMITED) 指对前多少个词进行建立索引
            indexWriter.addDocument(doc);//文档添加到索引库
            indexWriter.close();
        }
    
        private String readFile(File file) throws Exception{
            BufferedReader reader = new BufferedReader(new FileReader(file));
            StringBuffer content = new StringBuffer();
            for(String line=null; (line = reader.readLine())!=null;){
                content.append(line).append("\n");
            }
            return content.toString();
        }
    
        /**
         * 　　* @Description: 从索引库中搜索
         * 　　* @date 2019/5/21 11:14
         *
         */
        @Test
        public void search() throws Exception{
            //1.构建查询对象
            String queryString = "world";//需要查询的信息
            String[] fileds = {"name","content"};//需要查询的索引字段
            QueryParser queryParser = new MultiFieldQueryParser(fileds,standardAnalyzer);
            Query query = queryParser.parse(queryString);
    
            //2.进行查询
            IndexSearcher indexSearcher = new IndexSearcher(indexPath); //指定索引库位置 构建索引库查询操作对象
            Filter filter = null; //过滤器
            int docSize = 100000; //一次查询文档数目
            TopDocs topDocs = indexSearcher.search(query, filter, docSize);
            System.out.println("总共有条【"+topDocs.totalHits+"】匹配结果");
    
            //3.打印结果
            ScoreDoc[] scoreDocs = topDocs.scoreDocs;
            for(ScoreDoc scoreDoc : scoreDocs){
                int docIndex = scoreDoc.doc; //文档内部编号
                Document doc = indexSearcher.doc(docIndex);//根据文档编号获取对应文档
    
                System.out.println("------------------------");
                System.out.println("name:"+doc.get("name"));
                System.out.println("content:"+doc.get("content"));
                System.out.println("size:"+doc.get("size"));
                System.out.println("path:"+doc.get("path"));
            }
    
        }
    }

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