Lucene入门及实际项目应用场景

导入maven依赖

<dependency>
    <groupId>org.apache.lucene</groupId>
    <artifactId>lucene-core</artifactId>
    <version>5.3.1</version>
</dependency>
<dependency>
    <groupId>org.apache.lucene</groupId>
    <artifactId>lucene-queryparser</artifactId>
    <version>5.3.1</version>
</dependency>
<dependency>
    <groupId>org.apache.lucene</groupId>
    <artifactId>lucene-analyzers-common</artifactId>
    <version>5.3.1</version>
</dependency>

Helloword实现

生成索引

目的：索引数据目录，在指定目录生成索引文件

1、构造方法 实例化IndexWriter

　　 获取索引文件存放地址对象

　　获取输出流

　　设置输出流的对应配置

　　给输出流配置设置分词器

2、关闭索引输出流

3、索引指定路径下的所有文件

4、索引指定的文件

5、获取文档（索引文件中包含的重要信息，key-value的形式）

6、测试

package com.liuwenwu.lucene;

import java.io.File;
import java.io.FileReader;
import java.nio.file.Paths;

import org.apache.lucene.analysis.Analyzer;
import org.apache.lucene.analysis.standard.StandardAnalyzer;
import org.apache.lucene.document.Document;
import org.apache.lucene.document.Field;
import org.apache.lucene.document.TextField;
import org.apache.lucene.index.IndexWriter;
import org.apache.lucene.index.IndexWriterConfig;
import org.apache.lucene.store.FSDirectory;

/**
 * 配合Demo1.java进行lucene的helloword实现
 * @author Administrator
 *
 */
public class IndexCreate {
    private IndexWriter indexWriter;

    /**
     * 1、构造方法 实例化IndexWriter
     * @param indexDir
     * @throws Exception
     */
    public IndexCreate(String indexDir) throws Exception{
//        获取索引文件的存放地址对象
        FSDirectory dir = FSDirectory.open(Paths.get(indexDir));
//        标准分词器（针对英文）
        Analyzer analyzer = new StandardAnalyzer();
//        索引输出流配置对象
        IndexWriterConfig conf = new IndexWriterConfig(analyzer);
        indexWriter = new IndexWriter(dir, conf);
    }

    /**
     * 2、关闭索引输出流
     * @throws Exception
     */
    public void closeIndexWriter()  throws Exception{
        indexWriter.close();
    }

    /**
     * 3、索引指定路径下的所有文件
     * @param dataDir
     * @return
     * @throws Exception
     */
    public int index(String dataDir) throws Exception{
        File[] files = new File(dataDir).listFiles();
        for (File file : files) {
            indexFile(file);
        }
        return indexWriter.numDocs();
    }

    /**
     * 4、索引指定的文件
     * @param file
     * @throws Exception
     */
    private void indexFile(File file) throws Exception{
        System.out.println("被索引文件的全路径："+file.getCanonicalPath());
        Document doc = getDocument(file);
        indexWriter.addDocument(doc);
    }

    /**
     * 5、获取文档（索引文件中包含的重要信息，key-value的形式）
     * @param file
     * @return
     * @throws Exception
     */
    private Document getDocument(File file) throws Exception{
        Document doc = new Document();
        doc.add(new TextField("contents", new FileReader(file)));
//        Field.Store.YES是否存储到硬盘
        doc.add(new TextField("fullPath", file.getCanonicalPath(),Field.Store.YES));
        doc.add(new TextField("fileName", file.getName(),Field.Store.YES));
        return doc;
    }
}

package com.liuwenwu.lucene;

/**
 * 生成索引测试
 * @author Administrator
 *
 */
public class Demo1 {
    public static void main(String[] args) {
//        索引文件将要存放的位置
        String indexDir = "F:\\y2\\lucene\\demo1";
//        数据源地址
        String dataDir = "F:\\y2\\lucene\\demo1\\data";
        IndexCreate ic = null;
        try {
            ic = new IndexCreate(indexDir);
            long start = System.currentTimeMillis();
            int num = ic.index(dataDir);
            long end = System.currentTimeMillis();
            System.out.println("检索指定路径下"+num+"个文件，一共花费了"+(end-start)+"毫秒");
        } catch (Exception e) {
            e.printStackTrace();
        }finally {
            try {
                ic.closeIndexWriter();
            } catch (Exception e) {
                e.printStackTrace();
            }
        }
    }
}

结果：

使用索引

从索引文件中拿数据

1、获取输入流（通过dirReader）

2、获取索引搜索对象（通过输入流来拿）

3、获取查询对象（通过查询解析器来获取，解析器是通过分词器获取）

4、获取包含关键字排前面的文档对象集合

5、可以获取对应文档的内容

package com.liuwenwu.lucene;

import java.nio.file.Paths;

import org.apache.lucene.analysis.Analyzer;
import org.apache.lucene.analysis.standard.StandardAnalyzer;
import org.apache.lucene.document.Document;
import org.apache.lucene.index.DirectoryReader;
import org.apache.lucene.index.IndexReader;
import org.apache.lucene.queryparser.classic.QueryParser;
import org.apache.lucene.search.IndexSearcher;
import org.apache.lucene.search.Query;
import org.apache.lucene.search.ScoreDoc;
import org.apache.lucene.search.TopDocs;
import org.apache.lucene.store.FSDirectory;

/**
 * 配合Demo2.java进行lucene的helloword实现
 * @author Administrator
 *
 */
public class IndexUse {
    /**
     * 通过关键字在索引目录中查询
     * @param indexDir    索引文件所在目录
     * @param q    关键字
     */
    public static void search(String indexDir, String q) throws Exception{
        FSDirectory indexDirectory = FSDirectory.open(Paths.get(indexDir));
//        注意:索引输入流不是new出来的，是通过目录读取工具类打开的
        IndexReader indexReader = DirectoryReader.open(indexDirectory);
//        获取索引搜索对象
        IndexSearcher indexSearcher = new IndexSearcher(indexReader);
        Analyzer analyzer = new StandardAnalyzer();
//        查询解析器
        QueryParser queryParser = new QueryParser("contents", analyzer);
//        获取符合关键字的查询对象
        Query query = queryParser.parse(q);

        long start=System.currentTimeMillis();
//        获取关键字出现的前十次
        TopDocs topDocs = indexSearcher.search(query , 10);
        long end=System.currentTimeMillis();
        System.out.println("匹配 "+q+" ，总共花费"+(end-start)+"毫秒"+"查询到"+topDocs.totalHits+"个记录");

        for (ScoreDoc scoreDoc : topDocs.scoreDocs) {
            int docID = scoreDoc.doc;
//            索引搜索对象通过文档下标获取文档
            Document doc = indexSearcher.doc(docID);
            System.out.println("通过索引文件："+doc.get("fullPath")+"拿数据");
        }

        indexReader.close();
    }
}

package com.liuwenwu.lucene;

/**
 * 查询索引测试
 * @author Administrator
 *
 */
public class Demo2 {
    public static void main(String[] args) {
//        索引文件地址
        String indexDir = "F:\\y2\\lucene\\demo1";
//        搜索条件
        String q = "EarlyTerminating-Collector";
        try {
            IndexUse.search(indexDir, q);
        } catch (Exception e) {
            e.printStackTrace();
        }
    }
}

结果：

构建索引

package com.liuwenwu.lucene;

import java.nio.file.Paths;

import org.apache.lucene.analysis.Analyzer;
import org.apache.lucene.analysis.standard.StandardAnalyzer;
import org.apache.lucene.document.Document;
import org.apache.lucene.document.Field;
import org.apache.lucene.document.StringField;
import org.apache.lucene.document.TextField;
import org.apache.lucene.index.IndexWriter;
import org.apache.lucene.index.IndexWriterConfig;
import org.apache.lucene.index.Term;
import org.apache.lucene.store.FSDirectory;
import org.junit.Before;
import org.junit.Test;

/**
 * 构建索引
 *     对索引的增删改
 * @author Administrator
 *
 */
public class Demo3 {
    private String ids[]={"1","2","3"};
    private String citys[]={"qingdao","nanjing","shanghai"};
    private String descs[]={
            "Qingdao is a beautiful city.",
            "Nanjing is a city of culture.",
            "Shanghai is a bustling city."
    };
    private FSDirectory dir;

    /**
     * 每次都生成索引文件
     * @throws Exception
     */
    @Before
    public void setUp() throws Exception {
        dir  = FSDirectory.open(Paths.get("F:\\y2\\lucene\\demo2\\indexDir"));
        IndexWriter indexWriter = getIndexWriter();
        for (int i = 0; i < ids.length; i++) {
            Document doc = new Document();
            doc.add(new StringField("id", ids[i], Field.Store.YES));
            doc.add(new StringField("city", citys[i], Field.Store.YES));
            doc.add(new TextField("desc", descs[i], Field.Store.NO));
            indexWriter.addDocument(doc);
        }
        indexWriter.close();
    }

    /**
     * 获取索引输出流
     * @return
     * @throws Exception
     */
    private IndexWriter getIndexWriter()  throws Exception{
        Analyzer analyzer = new StandardAnalyzer();
        IndexWriterConfig conf = new IndexWriterConfig(analyzer);
        return new IndexWriter(dir, conf );
    }

    /**
     * 测试写了几个索引文件
     * @throws Exception
     */
    @Test
    public void getWriteDocNum() throws Exception {
        IndexWriter indexWriter = getIndexWriter();
        System.out.println("索引目录下生成"+indexWriter.numDocs()+"个索引文件");
    }

    /**
     * 打上标记，该索引实际并未删除
     * @throws Exception
     */
    @Test
    public void deleteDocBeforeMerge() throws Exception {
        IndexWriter indexWriter = getIndexWriter();
        System.out.println("最大文档数："+indexWriter.maxDoc());
        indexWriter.deleteDocuments(new Term("id", "1"));
        indexWriter.commit();

        System.out.println("最大文档数："+indexWriter.maxDoc());
        System.out.println("实际文档数："+indexWriter.numDocs());
        indexWriter.close();
    }

    /**
     * 对应索引文件已经删除,但是该版本的分词会保留
     * @throws Exception
     */
    @Test
    public void deleteDocAfterMerge() throws Exception {
//        https://blog.csdn.net/asdfsadfasdfsa/article/details/78820030
//        org.apache.lucene.store.LockObtainFailedException: Lock held by this virtual machine:indexWriter是单例的、线程安全的，不允许打开多个。
        IndexWriter indexWriter = getIndexWriter();
        System.out.println("最大文档数："+indexWriter.maxDoc());
        indexWriter.deleteDocuments(new Term("id", "1"));
        indexWriter.forceMergeDeletes(); //强制删除
        indexWriter.commit();

        System.out.println("最大文档数："+indexWriter.maxDoc());
        System.out.println("实际文档数："+indexWriter.numDocs());
        indexWriter.close();
    }

    /**
     * 测试更新索引
     * @throws Exception
     */
    @Test
    public void testUpdate()throws Exception{
        IndexWriter writer=getIndexWriter();
        Document doc=new Document();
        doc.add(new StringField("id", "1", Field.Store.YES));
        doc.add(new StringField("city","qingdao",Field.Store.YES));
        doc.add(new TextField("desc", "dsss is a city.", Field.Store.NO));
        writer.updateDocument(new Term("id","1"), doc);
        writer.close();
    }
}

新增索引

控制台

删除索引

控制台输出

合并前

合并后

注意：

大数据时用合并前的删除，知识给索引文件打标，定时清理打标的索引文件。

数据量不是特别大的时候，可以及时删除索引文件。

修改索引

通过可视化工具可发现

注意：5.3的版本修改前的分词不会消失。

文档域加权

相关代码

package com.liuwenwu.lucene;

import java.nio.file.Paths;

import org.apache.lucene.analysis.Analyzer;
import org.apache.lucene.analysis.standard.StandardAnalyzer;
import org.apache.lucene.document.Document;
import org.apache.lucene.document.Field;
import org.apache.lucene.document.StringField;
import org.apache.lucene.document.TextField;
import org.apache.lucene.index.DirectoryReader;
import org.apache.lucene.index.IndexReader;
import org.apache.lucene.index.IndexWriter;
import org.apache.lucene.index.IndexWriterConfig;
import org.apache.lucene.index.Term;
import org.apache.lucene.search.IndexSearcher;
import org.apache.lucene.search.Query;
import org.apache.lucene.search.ScoreDoc;
import org.apache.lucene.search.TermQuery;
import org.apache.lucene.search.TopDocs;
import org.apache.lucene.store.Directory;
import org.apache.lucene.store.FSDirectory;
import org.junit.Before;
import org.junit.Test;

/**
 * 文档域加权
 * @author Administrator
 *
 */
public class Demo4 {
    private String ids[]={"1","2","3","4"};
    private String authors[]={"Jack","Marry","John","Json"};
    private String positions[]={"accounting","technician","salesperson","boss"};
    private String titles[]={"Java is a good language.","Java is a cross platform language","Java powerful","You should learn java"};
    private String contents[]={
            "If possible, use the same JRE major version at both index and search time.",
            "When upgrading to a different JRE major version, consider re-indexing. ",
            "Different JRE major versions may implement different versions of Unicode,",
            "For example: with Java 1.4, `LetterTokenizer` will split around the character U+02C6,"
    };

    private Directory dir;//索引文件目录

    @Before
    public void setUp()throws Exception {
        dir = FSDirectory.open(Paths.get("F:\\y2\\lucene\\demo3\\indexDir"));
        IndexWriter writer = getIndexWriter();
        for (int i = 0; i < authors.length; i++) {
            Document doc = new Document();
            doc.add(new StringField("id", ids[i], Field.Store.YES));
            doc.add(new StringField("author", authors[i], Field.Store.YES));
            doc.add(new StringField("position", positions[i], Field.Store.YES));

            TextField textField = new TextField("title", titles[i], Field.Store.YES);

//            Json投钱做广告，把排名刷到第一了
            if("boss".equals(positions[i])) {
                textField.setBoost(2f);//设置权重，默认为1
            }

            doc.add(textField);
//            TextField会分词，StringField不会分词
            doc.add(new TextField("content", contents[i], Field.Store.NO));
            writer.addDocument(doc);
        }
        writer.close();

    }

    private IndexWriter getIndexWriter() throws Exception{
        Analyzer analyzer = new StandardAnalyzer();
        IndexWriterConfig conf = new IndexWriterConfig(analyzer);
        return new IndexWriter(dir, conf);
    }

    @Test
    public void index() throws Exception{
        IndexReader reader = DirectoryReader.open(dir);
        IndexSearcher searcher = new IndexSearcher(reader);
        String fieldName = "title";
        String keyWord = "java";
        Term t = new Term(fieldName, keyWord);
        Query query = new TermQuery(t);
        TopDocs hits = searcher.search(query, 10);
        System.out.println("关键字：‘"+keyWord+"’命中了"+hits.totalHits+"次");
        for (ScoreDoc scoreDoc : hits.scoreDocs) {
            Document doc = searcher.doc(scoreDoc.doc);
            System.out.println(doc.get("author"));
        }
    }

}

文档域加权前结果

文档域加权后结果变成

注意：关键字加权有利于排名的提升。

索引搜索功能

特定项搜索

代码

package com.liuwenwu.lucene;

import java.io.IOException;
import java.nio.file.Paths;

import org.apache.lucene.analysis.standard.StandardAnalyzer;
import org.apache.lucene.document.Document;
import org.apache.lucene.index.DirectoryReader;
import org.apache.lucene.index.IndexReader;
import org.apache.lucene.index.Term;
import org.apache.lucene.queryparser.classic.ParseException;
import org.apache.lucene.queryparser.classic.QueryParser;
import org.apache.lucene.search.IndexSearcher;
import org.apache.lucene.search.NumericRangeQuery;
import org.apache.lucene.search.ScoreDoc;
import org.apache.lucene.search.TermQuery;
import org.apache.lucene.search.TopDocs;
import org.apache.lucene.store.FSDirectory;
import org.junit.Before;
import org.junit.Test;

/**
 * 特定项搜索
 * 查询表达式（queryParser）
 * @author Administrator
 *
 */
public class Demo5 {
    @Before
    public void setUp() {
        // 索引文件将要存放的位置
        String indexDir = "F:\\y2\\lucene\\demo4";
        // 数据源地址
        String dataDir = "F:\\y2\\lucene\\demo4\\data";
        IndexCreate ic = null;
        try {
            ic = new IndexCreate(indexDir);
            long start = System.currentTimeMillis();
            int num = ic.index(dataDir);
            long end = System.currentTimeMillis();
            System.out.println("检索指定路径下" + num + "个文件，一共花费了" + (end - start) + "毫秒");

        } catch (Exception e) {
            e.printStackTrace();
        } finally {
            try {
                ic.closeIndexWriter();
            } catch (Exception e) {
                e.printStackTrace();
            }
        }
    }

    /**
     * 特定项搜索
     */
    @Test
    public void testTermQuery() {
        String indexDir = "F:\\y2\\lucene\\demo4";

        String fld = "contents";
        String text = "indexformattoooldexception";
//        特定项片段名和关键字
        Term t  = new Term(fld , text);
        TermQuery tq = new TermQuery(t  );
        try {
            FSDirectory indexDirectory = FSDirectory.open(Paths.get(indexDir));
//            注意:索引输入流不是new出来的，是通过目录读取工具类打开的
            IndexReader indexReader = DirectoryReader.open(indexDirectory);
//            获取索引搜索对象
            IndexSearcher is = new IndexSearcher(indexReader);

            TopDocs hits = is.search(tq, 100);
//            System.out.println(hits.totalHits);
            for(ScoreDoc scoreDoc: hits.scoreDocs) {
                Document doc = is.doc(scoreDoc.doc);
                System.out.println("文件"+doc.get("fullPath")+"中含有该关键字");

            }
        } catch (IOException e) {
            e.printStackTrace();
        }
    }

    /**
     * 查询表达式（queryParser）
     */
    @Test
    public void testQueryParser() {
        String indexDir = "F:\\y2\\lucene\\demo4";
//        获取查询解析器（通过哪种分词器去解析哪种片段）
        QueryParser queryParser = new QueryParser("contents", new StandardAnalyzer());
        try {
            FSDirectory indexDirectory = FSDirectory.open(Paths.get(indexDir));
//            注意:索引输入流不是new出来的，是通过目录读取工具类打开的
            IndexReader indexReader = DirectoryReader.open(indexDirectory);
//            获取索引搜索对象
            IndexSearcher is = new IndexSearcher(indexReader);

//            由解析器去解析对应的关键字
            TopDocs hits = is.search(queryParser.parse("indexformattoooldexception") , 100);
            for(ScoreDoc scoreDoc: hits.scoreDocs) {
                Document doc = is.doc(scoreDoc.doc);
                System.out.println("文件"+doc.get("fullPath")+"中含有该关键字");

            }
        } catch (IOException e) {
            e.printStackTrace();
        } catch (ParseException e) {
            // TODO Auto-generated catch block
            e.printStackTrace();
        }
    }

}

控制台结果

Lucene查看工具

查询表达式（queryParser）

    /**
     * 查询表达式（queryParser）
     */
    @Test
    public void testQueryParser() {
        String indexDir = "F:\\y2\\lucene\\demo4";
//        获取查询解析器（通过哪种分词器去解析哪种片段）
        QueryParser queryParser = new QueryParser("contents", new StandardAnalyzer());
        try {
            FSDirectory indexDirectory = FSDirectory.open(Paths.get(indexDir));
//            注意:索引输入流不是new出来的，是通过目录读取工具类打开的
            IndexReader indexReader = DirectoryReader.open(indexDirectory);
//            获取索引搜索对象
            IndexSearcher is = new IndexSearcher(indexReader);

//            由解析器去解析对应的关键字
            TopDocs hits = is.search(queryParser.parse("indexformattoooldexception") , 100);
            for(ScoreDoc scoreDoc: hits.scoreDocs) {
                Document doc = is.doc(scoreDoc.doc);
                System.out.println("文件"+doc.get("fullPath")+"中含有该关键字");

            }
        } catch (IOException e) {
            e.printStackTrace();
        } catch (ParseException e) {
            // TODO Auto-generated catch block
            e.printStackTrace();
        }
    }

注意：与特定项搜索结果一样的。但是，特定项搜索是没有指定分词器的。

分页功能

方案一

一次全部查出来到session中，分页的时候从session中那集合截取显示。优势是只要查询一次，缺陷是占用内存。并发的可能性很高。得到命中文档数组，通过下标拿命中文档，从而获取内容。

方案二

每次上一页下一页都是一次查询，占用时间。但是通常少有人点击下一页、得到命中文档数组，通过下标拿命中文档，从而获取内容。

推荐：使用第二种方案

其他查询方法

指定数字范围查询（numbericRangeQuery）

package com.liuwenwu.lucene;

import java.nio.file.Paths;

import org.apache.lucene.analysis.Analyzer;
import org.apache.lucene.analysis.standard.StandardAnalyzer;
import org.apache.lucene.document.Document;
import org.apache.lucene.document.Field;
import org.apache.lucene.document.IntField;
import org.apache.lucene.document.StringField;
import org.apache.lucene.document.TextField;
import org.apache.lucene.index.DirectoryReader;
import org.apache.lucene.index.IndexReader;
import org.apache.lucene.index.IndexWriter;
import org.apache.lucene.index.IndexWriterConfig;
import org.apache.lucene.index.Term;
import org.apache.lucene.search.BooleanClause;
import org.apache.lucene.search.BooleanQuery;
import org.apache.lucene.search.IndexSearcher;
import org.apache.lucene.search.NumericRangeQuery;
import org.apache.lucene.search.PrefixQuery;
import org.apache.lucene.search.ScoreDoc;
import org.apache.lucene.search.TopDocs;
import org.apache.lucene.store.FSDirectory;
import org.junit.Before;
import org.junit.Test;

/**
 * 指定数字范围查询
 * 指定字符串开头字母查询（prefixQuery）
 * @author Administrator
 *
 */
public class Demo6 {
    private int ids[]={1,2,3};
    private String citys[]={"qingdao","nanjing","shanghai"};
    private String descs[]={
            "Qingdao is a beautiful city.",
            "Nanjing is a city of culture.",
            "Shanghai is a bustling city."
    };
    private FSDirectory dir;

    /**
     * 每次都生成索引文件
     * @throws Exception
     */
    @Before
    public void setUp() throws Exception {
        dir  = FSDirectory.open(Paths.get("F:\\y2\\lucene\\demo2\\indexDir"));
        IndexWriter indexWriter = getIndexWriter();
        for (int i = 0; i < ids.length; i++) {
            Document doc = new Document();
            doc.add(new IntField("id", ids[i], Field.Store.YES));
            doc.add(new StringField("city", citys[i], Field.Store.YES));
            doc.add(new TextField("desc", descs[i], Field.Store.YES));
            indexWriter.addDocument(doc);
        }
        indexWriter.close();
    }

    /**
     * 获取索引输出流
     * @return
     * @throws Exception
     */
    private IndexWriter getIndexWriter()  throws Exception{
        Analyzer analyzer = new StandardAnalyzer();
        IndexWriterConfig conf = new IndexWriterConfig(analyzer);
        return new IndexWriter(dir, conf );
    }

    /**
     * 指定数字范围查询
     * @throws Exception
     */
    @Test
    public void testNumericRangeQuery()throws Exception{
        IndexReader reader = DirectoryReader.open(dir);
        IndexSearcher is = new IndexSearcher(reader);

        NumericRangeQuery<Integer> query=NumericRangeQuery.newIntRange("id", 1, 2, true, true);
        TopDocs hits=is.search(query, 10);
        for(ScoreDoc scoreDoc:hits.scoreDocs){
            Document doc=is.doc(scoreDoc.doc);
            System.out.println(doc.get("id"));
            System.out.println(doc.get("city"));
            System.out.println(doc.get("desc"));
        }
    }

    /**
     * 指定字符串开头字母查询（prefixQuery）
     * @throws Exception
     */
    @Test
    public void testPrefixQuery()throws Exception{
        IndexReader reader = DirectoryReader.open(dir);
        IndexSearcher is = new IndexSearcher(reader);

        PrefixQuery query=new PrefixQuery(new Term("city","n"));
        TopDocs hits=is.search(query, 10);
        for(ScoreDoc scoreDoc:hits.scoreDocs){
            Document doc=is.doc(scoreDoc.doc);
            System.out.println(doc.get("id"));
            System.out.println(doc.get("city"));
            System.out.println(doc.get("desc"));
        }
    }

    /**
     * 组合查询
     * @throws Exception
     */
    @Test
    public void testBooleanQuery()throws Exception{
        IndexReader reader = DirectoryReader.open(dir);
        IndexSearcher is = new IndexSearcher(reader);

        NumericRangeQuery<Integer> query1=NumericRangeQuery.newIntRange("id", 1, 2, true, true);
        PrefixQuery query2=new PrefixQuery(new Term("city","n"));
        BooleanQuery.Builder booleanQuery=new BooleanQuery.Builder();
        booleanQuery.add(query1,BooleanClause.Occur.MUST);
        booleanQuery.add(query2,BooleanClause.Occur.MUST);
        TopDocs hits=is.search(booleanQuery.build(), 10);
        for(ScoreDoc scoreDoc:hits.scoreDocs){
            Document doc=is.doc(scoreDoc.doc);
            System.out.println(doc.get("id"));
            System.out.println(doc.get("city"));
            System.out.println(doc.get("desc"));
        }
    }
}

指定字符串开头字母查询（prefixQuery）

    /**
     * 指定字符串开头字母查询（prefixQuery）
     * @throws Exception
     */
    @Test
    public void testPrefixQuery()throws Exception{
        IndexReader reader = DirectoryReader.open(dir);
        IndexSearcher is = new IndexSearcher(reader);

        PrefixQuery query=new PrefixQuery(new Term("city","n"));
        TopDocs hits=is.search(query, 10);
        for(ScoreDoc scoreDoc:hits.scoreDocs){
            Document doc=is.doc(scoreDoc.doc);
            System.out.println(doc.get("id"));
            System.out.println(doc.get("city"));
            System.out.println(doc.get("desc"));
        }
    }

组合查询（booleanQuery）重点

Must、must not、should

    /**
     * 组合查询
     * @throws Exception
     */
    @Test
    public void testBooleanQuery()throws Exception{
        IndexReader reader = DirectoryReader.open(dir);
        IndexSearcher is = new IndexSearcher(reader);

        NumericRangeQuery<Integer> query1=NumericRangeQuery.newIntRange("id", 1, 2, true, true);
        PrefixQuery query2=new PrefixQuery(new Term("city","n"));
        BooleanQuery.Builder booleanQuery=new BooleanQuery.Builder();
        booleanQuery.add(query1,BooleanClause.Occur.MUST);
        booleanQuery.add(query2,BooleanClause.Occur.MUST);
        TopDocs hits=is.search(booleanQuery.build(), 10);
        for(ScoreDoc scoreDoc:hits.scoreDocs){
            Document doc=is.doc(scoreDoc.doc);
            System.out.println(doc.get("id"));
            System.out.println(doc.get("city"));
            System.out.println(doc.get("desc"));
        }
    }

中文分词&&高亮显示

private Integer ids[]={1,2,3};
    private String citys[]={"青岛","南京","上海"};
    private String descs[]={
            "青岛是个美丽的城市。",
            "南京是个有文化的城市。",
            "上海市个繁华的城市。"
    };

为了查看高亮显示效果

南京是一个文化的城市南京，简称宁，是江苏省会，地处中国东部地区，长江下游，濒江近海。全市下辖11个区，总面积6597平方公里，2013年建成区面积752.83平方公里，常住人口818.78万，其中城镇人口659.1万人。[1-4] “江南佳丽地，金陵帝王州”，南京拥有着6000多年文明史、近2600年建城史和近500年的建都史，是中国四大古都之一，有“六朝古都”、“十朝都会”之称，是中华文明的重要发祥地，历史上曾数次庇佑华夏之正朔，长期是中国南方的政治、经济、文化中心，拥有厚重的文化底蕴和丰富的历史遗存。[5-7] 南京是国家重要的科教中心，自古以来就是一座崇文重教的城市，有“天下文枢”、“东南第一学”的美誉。截至2013年，南京有高等院校75所，其中211高校8所，仅次于北京上海；国家重点实验室25所、国家重点学科169个、两院院士83人，均居中国第三。[8-10] 。",

使用标准分词器对中文进行分词的结果如下

把每个字都当作了一个词，并没有达到我们想要的效果，也就是说标准分词器StandardAnalyzer已经不能满足我们的开发需要了。

中文分词

依赖

<dependency>
    <groupId>org.apache.lucene</groupId>
    <artifactId>lucene-analyzers-smartcn</artifactId>
    <version>5.3.1</version>
</dependency>

将标准分词器换成中文分词器

结果如下：

高亮显示

依赖

<dependency>
    <groupId>org.apache.lucene</groupId>
    <artifactId>lucene-highlighter</artifactId>
    <version>5.3.1</version>
</dependency>

高亮显示的步奏：

1、通过查询对象，获取查询得分对象

2、通过得分对象，获取对应的片段

3、实例化一个html格式化对象

4、通过html格式化实例和查询得分实例，来实例化Lucene提供的高亮显示类对象。

5、将前面获取到的得分片段，设置到高亮显示的的实例对象中。

6、通过分词器获取TokenStream令牌流对象

7、通过令牌和原有的片段，去拿高亮展示后的片段

相关代码：

package com.liuwenwu.lucene;

import java.io.StringReader;
import java.nio.file.Paths;

import org.apache.lucene.analysis.Analyzer;
import org.apache.lucene.analysis.TokenStream;
import org.apache.lucene.analysis.cn.smart.SmartChineseAnalyzer;
import org.apache.lucene.analysis.standard.StandardAnalyzer;
import org.apache.lucene.document.Document;
import org.apache.lucene.document.Field;
import org.apache.lucene.document.IntField;
import org.apache.lucene.document.StringField;
import org.apache.lucene.document.TextField;
import org.apache.lucene.index.DirectoryReader;
import org.apache.lucene.index.IndexReader;
import org.apache.lucene.index.IndexWriter;
import org.apache.lucene.index.IndexWriterConfig;
import org.apache.lucene.queryparser.classic.QueryParser;
import org.apache.lucene.search.IndexSearcher;
import org.apache.lucene.search.Query;
import org.apache.lucene.search.ScoreDoc;
import org.apache.lucene.search.TopDocs;
import org.apache.lucene.search.highlight.Highlighter;
import org.apache.lucene.search.highlight.QueryScorer;
import org.apache.lucene.search.highlight.SimpleHTMLFormatter;
import org.apache.lucene.search.highlight.SimpleSpanFragmenter;
import org.apache.lucene.store.FSDirectory;
import org.junit.Before;
import org.junit.Test;

/**
 * 中文分词器
 * 高亮显示
 * @author ASUS
 *
 */
public class Demo7 {
    private Integer ids[] = { 1, 2, 3 };
    private String citys[] = { "青岛", "南京", "上海" };
    // private String descs[]={
    // "青岛是个美丽的城市。",
    // "南京是个有文化的城市。",
    // "上海市个繁华的城市。"
    // };
    private String descs[] = { "青岛是个美丽的城市。",
            "南京是一个文化的城市南京，简称宁，是江苏省会，地处中国东部地区，长江下游，濒江近海。全市下辖11个区，总面积6597平方公里，2013年建成区面积752.83平方公里，常住人口818.78万，其中城镇人口659.1万人。[1-4] “江南佳丽地，金陵帝王州”，南京拥有着6000多年文明史、近2600年建城史和近500年的建都史，是中国四大古都之一，有“六朝古都”、“十朝都会”之称，是中华文明的重要发祥地，历史上曾数次庇佑华夏之正朔，长期是中国南方的政治、经济、文化中心，拥有厚重的文化底蕴和丰富的历史遗存。[5-7] 南京是国家重要的科教中心，自古以来就是一座崇文重教的城市，有“天下文枢”、“东南第一学”的美誉。截至2013年，南京有高等院校75所，其中211高校8所，仅次于北京上海；国家重点实验室25所、国家重点学科169个、两院院士83人，均居中国第三。[8-10]",
            "上海市个繁华的城市。" };

    private FSDirectory dir;

    /**
     * 每次都生成索引文件
     *
     * @throws Exception
     */
    @Before
    public void setUp() throws Exception {
        dir = FSDirectory.open(Paths.get("F:\\y2\\lucene\\demo2\\indexDir"));
        IndexWriter indexWriter = getIndexWriter();
        for (int i = 0; i < ids.length; i++) {
            Document doc = new Document();
            doc.add(new IntField("id", ids[i], Field.Store.YES));
            doc.add(new StringField("city", citys[i], Field.Store.YES));
            doc.add(new TextField("desc", descs[i], Field.Store.YES));
            indexWriter.addDocument(doc);
        }
        indexWriter.close();
    }

    /**
     * 获取索引输出流
     *
     * @return
     * @throws Exception
     */
    private IndexWriter getIndexWriter() throws Exception {
//        Analyzer analyzer = new StandardAnalyzer();
        Analyzer analyzer = new SmartChineseAnalyzer();
        IndexWriterConfig conf = new IndexWriterConfig(analyzer);
        return new IndexWriter(dir, conf);
    }

    /**
     * luke查看索引生成
     *
     * @throws Exception
     */
    @Test
    public void testIndexCreate() throws Exception {

    }

    /**
     * 测试高亮
     *
     * @throws Exception
     */
    @Test
    public void testHeight() throws Exception {
        IndexReader reader = DirectoryReader.open(dir);
        IndexSearcher searcher = new IndexSearcher(reader);

        SmartChineseAnalyzer analyzer = new SmartChineseAnalyzer();
        QueryParser parser = new QueryParser("desc", analyzer);
        // Query query = parser.parse("南京文化");
        Query query = parser.parse("南京文明");
        TopDocs hits = searcher.search(query, 100);

        // 查询得分项
        QueryScorer queryScorer = new QueryScorer(query);
        // 得分项对应的内容片段
        SimpleSpanFragmenter fragmenter = new SimpleSpanFragmenter(queryScorer);
        // 高亮显示的样式
        SimpleHTMLFormatter htmlFormatter = new SimpleHTMLFormatter("<span color='red'><b>", "</b></span>");
        // 高亮显示对象
        Highlighter highlighter = new Highlighter(htmlFormatter, queryScorer);
        // 设置需要高亮显示对应的内容片段
        highlighter.setTextFragmenter(fragmenter);

        for (ScoreDoc scoreDoc : hits.scoreDocs) {
            Document doc = searcher.doc(scoreDoc.doc);
            String desc = doc.get("desc");
            if (desc != null) {
                // tokenstream是从doucment的域（field)中抽取的一个个分词而组成的一个数据流，用于分词。
                TokenStream tokenStream = analyzer.tokenStream("desc", new StringReader(desc));
                System.out.println("高亮显示的片段：" + highlighter.getBestFragment(tokenStream, desc));
            }
            System.out.println("所有内容：" + desc);
        }

    }

}

控制台结果：

南京文明结果：

高亮显示的片段：城镇人口659.1万人。[1-4] “江南佳丽地，金陵帝王州”，<span color='red'><b>南京</b></span>拥有着6000多年<span color='red'><b>文明</b></span>史、近2600年建城史和近500年的建都史，是中国四大古都之一，有“六朝古都”、“十朝都会”之称，是中华<span color='red'><b>文明</b></span>的
所有内容：南京是一个文化的城市南京，简称宁，是江苏省会，地处中国东部地区，长江下游，濒江近海。全市下辖11个区，总面积6597平方公里，2013年建成区面积752.83平方公里，常住人口818.78万，其中城镇人口659.1万人。[1-4] “江南佳丽地，金陵帝王州”，南京拥有着6000多年文明史、近2600年建城史和近500年的建都史，是中国四大古都之一，有“六朝古都”、“十朝都会”之称，是中华文明的重要发祥地，历史上曾数次庇佑华夏之正朔，长期是中国南方的政治、经济、文化中心，拥有厚重的文化底蕴和丰富的历史遗存。[5-7] 南京是国家重要的科教中心，自古以来就是一座崇文重教的城市，有“天下文枢”、“东南第一学”的美誉。截至2013年，南京有高等院校75所，其中211高校8所，仅次于北京上海；国家重点实验室25所、国家重点学科169个、两院院士83人，均居中国第三。[8-10]

Lucene中各个核心类的作用：https://blog.csdn.net/kevinelstri/article/details/52317977

综合案例

核心代码

<properties>
        <httpclient.version>4.5.2</httpclient.version>
        <jsoup.version>1.10.1</jsoup.version>
        <!-- <lucene.version>7.1.0</lucene.version> -->
        <lucene.version>5.3.1</lucene.version>
        <ehcache.version>2.10.3</ehcache.version>
        <junit.version>4.12</junit.version>
        <log4j.version>1.2.16</log4j.version>
        <mysql.version>5.1.44</mysql.version>
        <fastjson.version>1.2.47</fastjson.version>
        <struts2.version>2.5.16</struts2.version>
        <servlet.version>4.0.1</servlet.version>
        <jstl.version>1.2</jstl.version>
        <standard.version>1.1.2</standard.version>
        <tomcat-jsp-api.version>8.0.47</tomcat-jsp-api.version>
    </properties>
    <dependencies>
        <dependency>
            <groupId>junit</groupId>
            <artifactId>junit</artifactId>
            <version>${junit.version}</version>
            <scope>test</scope>
        </dependency>

        <!-- jdbc驱动包 -->
        <dependency>
            <groupId>mysql</groupId>
            <artifactId>mysql-connector-java</artifactId>
            <version>${mysql.version}</version>
        </dependency>

        <!-- 添加Httpclient支持 -->
        <dependency>
            <groupId>org.apache.httpcomponents</groupId>
            <artifactId>httpclient</artifactId>
            <version>${httpclient.version}</version>
        </dependency>

        <!-- 添加jsoup支持 -->
        <dependency>
            <groupId>org.jsoup</groupId>
            <artifactId>jsoup</artifactId>
            <version>${jsoup.version}</version>
        </dependency>

        <!-- 添加日志支持 -->
        <dependency>
            <groupId>log4j</groupId>
            <artifactId>log4j</artifactId>
            <version>${log4j.version}</version>
        </dependency>

        <!-- 添加ehcache支持 -->
        <dependency>
            <groupId>net.sf.ehcache</groupId>
            <artifactId>ehcache</artifactId>
            <version>${ehcache.version}</version>
        </dependency>

        <dependency>
            <groupId>com.alibaba</groupId>
            <artifactId>fastjson</artifactId>
            <version>${fastjson.version}</version>
        </dependency>

        <dependency>
            <groupId>org.apache.struts</groupId>
            <artifactId>struts2-core</artifactId>
            <version>${struts2.version}</version>
        </dependency>

        <dependency>
            <groupId>javax.servlet</groupId>
            <artifactId>javax.servlet-api</artifactId>
            <version>${servlet.version}</version>
            <scope>provided</scope>
        </dependency>

        <dependency>
            <groupId>org.apache.lucene</groupId>
            <artifactId>lucene-core</artifactId>
            <version>${lucene.version}</version>
        </dependency>
        <dependency>
            <groupId>org.apache.lucene</groupId>
            <artifactId>lucene-queryparser</artifactId>
            <version>${lucene.version}</version>
        </dependency>
        <!-- <dependency> <groupId>org.apache.lucene</groupId> <artifactId>lucene-analyzers-common</artifactId>
            <version>${lucene.version}</version> </dependency> -->

        <dependency>
            <groupId>org.apache.lucene</groupId>
            <artifactId>lucene-analyzers-smartcn</artifactId>
            <version>${lucene.version}</version>
        </dependency>

        <dependency>
            <groupId>org.apache.lucene</groupId>
            <artifactId>lucene-highlighter</artifactId>
            <version>${lucene.version}</version>
        </dependency>

        <!-- 5.3、jstl、standard -->
        <dependency>
            <groupId>jstl</groupId>
            <artifactId>jstl</artifactId>
            <version>${jstl.version}</version>
        </dependency>
        <dependency>
            <groupId>taglibs</groupId>
            <artifactId>standard</artifactId>
            <version>${standard.version}</version>
        </dependency>

        <!-- 5.4、tomcat-jsp-api -->
        <dependency>
            <groupId>org.apache.tomcat</groupId>
            <artifactId>tomcat-jsp-api</artifactId>
            <version>${tomcat-jsp-api.version}</version>
        </dependency>
    </dependencies>

package com.liuwenwu.blog.web;

import java.util.ArrayList;
import java.util.HashMap;
import java.util.List;
import java.util.Map;

import javax.servlet.http.HttpServletRequest;

import org.apache.lucene.analysis.cn.smart.SmartChineseAnalyzer;
import org.apache.lucene.document.Document;
import org.apache.lucene.index.DirectoryReader;
import org.apache.lucene.queryparser.classic.QueryParser;
import org.apache.lucene.search.IndexSearcher;
import org.apache.lucene.search.Query;
import org.apache.lucene.search.ScoreDoc;
import org.apache.lucene.search.TopDocs;
import org.apache.lucene.search.highlight.Highlighter;
import org.apache.lucene.store.Directory;
import org.apache.struts2.ServletActionContext;

import com.liuwenwu.blog.dao.BlogDao;
import com.liuwenwu.blog.util.LuceneUtil;
import com.liuwenwu.blog.util.PropertiesUtil;
import com.liuwenwu.blog.util.StringUtils;

/**
 * IndexReader
 * IndexSearcher
 * Highlighter
 * @author Administrator
 *
 */
public class BlogAction {
    private String title;
    private BlogDao blogDao = new BlogDao();

    public String getTitle() {
        return title;
    }

    public void setTitle(String title) {
        this.title = title;
    }

    public String list() {
        try {
            HttpServletRequest request = ServletActionContext.getRequest();
            if (StringUtils.isBlank(title)) {
                List<Map<String, Object>> blogList = this.blogDao.list(title, null);
                request.setAttribute("blogList", blogList);
            }else {
                Directory directory = LuceneUtil.getDirectory(PropertiesUtil.getValue("indexPath"));
                DirectoryReader reader = LuceneUtil.getDirectoryReader(directory);
                IndexSearcher searcher = LuceneUtil.getIndexSearcher(reader);
                SmartChineseAnalyzer analyzer = new SmartChineseAnalyzer();
//                拿一句话到索引目中的索引文件中的词库进行关键词碰撞
                Query query = new QueryParser("title", analyzer).parse(title);
                Highlighter highlighter = LuceneUtil.getHighlighter(query, "title");

                TopDocs topDocs = searcher.search(query , 100);
                //处理得分命中的文档
                List<Map<String, Object>> blogList = new ArrayList<>();
                Map<String, Object> map = null;
                ScoreDoc[] scoreDocs = topDocs.scoreDocs;
                for (ScoreDoc scoreDoc : scoreDocs) {
                    map = new HashMap<>();
                    Document doc = searcher.doc(scoreDoc.doc);
                    map.put("id", doc.get("id"));
                    String titleHighlighter = doc.get("title");
                    if(StringUtils.isNotBlank(titleHighlighter)) {
                        titleHighlighter = highlighter.getBestFragment(analyzer, "title", titleHighlighter);
                    }
                    map.put("title", titleHighlighter);
                    map.put("url", doc.get("url"));
                    blogList.add(map);
                }

                request.setAttribute("blogList", blogList);
            }
        } catch (Exception e) {
            e.printStackTrace();
        }
        return "blogList";
    }
}

package com.liuwenwu.blog.web;

import java.io.IOException;
import java.nio.file.Paths;
import java.sql.SQLException;
import java.util.List;
import java.util.Map;

import org.apache.lucene.analysis.cn.smart.SmartChineseAnalyzer;
import org.apache.lucene.document.Document;
import org.apache.lucene.document.Field;
import org.apache.lucene.document.StringField;
import org.apache.lucene.document.TextField;
import org.apache.lucene.index.IndexWriter;
import org.apache.lucene.index.IndexWriterConfig;
import org.apache.lucene.store.Directory;
import org.apache.lucene.store.FSDirectory;

import com.liuwenwu.blog.dao.BlogDao;
import com.liuwenwu.blog.util.PropertiesUtil;

/**
 * 构建lucene索引
 * @author Administrator
 * 1。构建索引    IndexWriter
 * 2、读取索引文件，获取命中片段
 * 3、使得命中片段高亮显示
 *
 */
public class IndexStarter {
    private static BlogDao blogDao = new BlogDao();
    public static void main(String[] args) {
        IndexWriterConfig conf = new IndexWriterConfig(new SmartChineseAnalyzer());
        Directory d;
        IndexWriter indexWriter = null;
        try {
            d = FSDirectory.open(Paths.get(PropertiesUtil.getValue("indexPath")));
            indexWriter = new IndexWriter(d , conf );

//            为数据库中的所有数据构建索引
            List<Map<String, Object>> list = blogDao.list(null, null);
            for (Map<String, Object> map : list) {
                Document doc = new Document();
                doc.add(new StringField("id", (String) map.get("id"), Field.Store.YES));
//                TextField用于对一句话分词处理    java培训机构
                doc.add(new TextField("title", (String) map.get("title"), Field.Store.YES));
                doc.add(new StringField("url", (String) map.get("url"), Field.Store.YES));
                indexWriter.addDocument(doc);
            }

        } catch (IOException e) {
            e.printStackTrace();
        } catch (InstantiationException e) {
            e.printStackTrace();
        } catch (IllegalAccessException e) {
            e.printStackTrace();
        } catch (SQLException e) {
            e.printStackTrace();
        }finally {
            try {
                if(indexWriter!= null) {
                    indexWriter.close();
                }
            } catch (IOException e) {
                // TODO Auto-generated catch block
                e.printStackTrace();
            }
        }
    }
}

package com.liuwenwu.blog.util;

import java.io.IOException;
import java.nio.file.Paths;
import org.apache.lucene.analysis.Analyzer;
import org.apache.lucene.index.DirectoryReader;
import org.apache.lucene.index.IndexWriter;
import org.apache.lucene.index.IndexWriterConfig;
import org.apache.lucene.index.IndexWriterConfig.OpenMode;
import org.apache.lucene.search.IndexSearcher;
import org.apache.lucene.search.Query;
import org.apache.lucene.search.highlight.Formatter;
import org.apache.lucene.search.highlight.Highlighter;
import org.apache.lucene.search.highlight.QueryTermScorer;
import org.apache.lucene.search.highlight.Scorer;
import org.apache.lucene.search.highlight.SimpleFragmenter;
import org.apache.lucene.search.highlight.SimpleHTMLFormatter;
import org.apache.lucene.store.Directory;
import org.apache.lucene.store.FSDirectory;
import org.apache.lucene.store.RAMDirectory;

/**
 * lucene工具类
 * @author Administrator
 *
 */
public class LuceneUtil {

    /**
     * 获取索引文件存放的文件夹对象
     *
     * @param path
     * @return
     */
    public static Directory getDirectory(String path) {
        Directory directory = null;
        try {
            directory = FSDirectory.open(Paths.get(path));
        } catch (IOException e) {
            e.printStackTrace();
        }
        return directory;
    }

    /**
     * 索引文件存放在内存
     *
     * @return
     */
    public static Directory getRAMDirectory() {
        Directory directory = new RAMDirectory();
        return directory;
    }

    /**
     * 文件夹读取对象
     *
     * @param directory
     * @return
     */
    public static DirectoryReader getDirectoryReader(Directory directory) {
        DirectoryReader reader = null;
        try {
            reader = DirectoryReader.open(directory);
        } catch (IOException e) {
            e.printStackTrace();
        }
        return reader;
    }

    /**
     * 文件索引对象
     *
     * @param reader
     * @return
     */
    public static IndexSearcher getIndexSearcher(DirectoryReader reader) {
        IndexSearcher indexSearcher = new IndexSearcher(reader);
        return indexSearcher;
    }

    /**
     * 写入索引对象
     *
     * @param directory
     * @param analyzer
     * @return
     */
    public static IndexWriter getIndexWriter(Directory directory, Analyzer analyzer)

    {
        IndexWriter iwriter = null;
        try {
            IndexWriterConfig config = new IndexWriterConfig(analyzer);
            config.setOpenMode(OpenMode.CREATE_OR_APPEND);
            // Sort sort=new Sort(new SortField("content", Type.STRING));
            // config.setIndexSort(sort);//排序
            config.setCommitOnClose(true);
            // 自动提交
            // config.setMergeScheduler(new ConcurrentMergeScheduler());
            // config.setIndexDeletionPolicy(new
            // SnapshotDeletionPolicy(NoDeletionPolicy.INSTANCE));
            iwriter = new IndexWriter(directory, config);
        } catch (IOException e) {
            e.printStackTrace();
        }
        return iwriter;
    }

    /**
     * 关闭索引文件生成对象以及文件夹对象
     *
     * @param indexWriter
     * @param directory
     */
    public static void close(IndexWriter indexWriter, Directory directory) {
        if (indexWriter != null) {
            try {
                indexWriter.close();
            } catch (IOException e) {
                indexWriter = null;
            }
        }
        if (directory != null) {
            try {
                directory.close();
            } catch (IOException e) {
                directory = null;
            }
        }
    }

    /**
     * 关闭索引文件读取对象以及文件夹对象
     *
     * @param reader
     * @param directory
     */
    public static void close(DirectoryReader reader, Directory directory) {
        if (reader != null) {
            try {
                reader.close();
            } catch (IOException e) {
                reader = null;
            }
        }
        if (directory != null) {
            try {
                directory.close();
            } catch (IOException e) {
                directory = null;
            }
        }

    }

    /**
     * 高亮标签
     *
     * @param query
     * @param fieldName
     * @return
     */

    public static Highlighter getHighlighter(Query query, String fieldName)
    {
        Formatter formatter = new SimpleHTMLFormatter("<span style='color:red'>", "</span>");
        Scorer fragmentScorer = new QueryTermScorer(query, fieldName);
        Highlighter highlighter = new Highlighter(formatter, fragmentScorer);
        highlighter.setTextFragmenter(new SimpleFragmenter(200));
        return highlighter;
    }
}