只用了几百行代码写的百度搜索引擎，你看咋样？

writer.addDocument(document);
writer.commit();
writer.close();
}

public void addModelDocs(List objects) throws IOException {
if (CollectionUtils.isNotEmpty(objects)) {
List docs = new ArrayList<>();
objects.forEach(o -> {
Document document = new Document();
List fields = luceneField(o);
fields.forEach(document::add);
docs.add(document);
});
writer.addDocuments(docs);
}
}

public void delAllDocs() throws IOException {
writer.deleteAll();
}

public void addDocs(List docs) throws IOException {
if (CollectionUtils.isNotEmpty(docs)) {
long startTime = System.currentTimeMillis();
writer.addDocuments(docs);
writer.commit();
log.info(“共索引{}个 Document，共耗时{} 毫秒”, docs.size(), (System.currentTimeMillis() - startTime));
} else {
log.warn(“索引列表为空”);
}
}

public List luceneField(Object modelObj) {
Map classFields = ReflectionUtils.getClassFields(modelObj.getClass());
Map classFieldsValues = ReflectionUtils.getClassFieldsValues(modelObj);

List fields = new ArrayList<>();
for (String key : classFields.keySet()) {
Field field;
String dataType = StringUtils.substringAfterLast(classFields.get(key).toString(), “.”);
switch (dataType) {
case “Integer”:
field = new IntPoint(key, (Integer) classFieldsValues.get(key));
break;
case “Long”:
field = new LongPoint(key, (Long) classFieldsValues.get(key));
break;
case “Float”:
field = new FloatPoint(key, (Float) classFieldsValues.get(key));
break;
case “Double”:
field = new DoublePoint(key, (Double) classFieldsValues.get(key));
break;
case “String”:
String string = (String) classFieldsValues.get(key);
if (StringUtils.isNotBlank(string)) {
if (string.length() <= 1024) {
field = new StringField(key, (String) classFieldsValues.get(key), Field.Store.YES);
} else {
field = new TextField(key, (String) classFieldsValues.get(key), Field.Store.NO);
}
} else {
field = new StringField(key, StringUtils.EMPTY, Field.Store.NO);
}
break;
default:
field = new TextField(key, JsonUtils.obj2Json(classFieldsValues.get(key)), Field.Store.YES);
break;
}
fields.add(field);
}
return fields;
}
public void close() {
if (null != writer) {
try {
writer.close();
} catch (IOException e) {
log.error(“close writer error”);
}
writer = null;
}
}

public void commit() throws IOException {
if (null != writer) {
writer.commit();
writer.close();
}
}
}

有了工具类，我们再写一个 demo 来进行数据的索引

import java.util.ArrayList;
import java.util.List;

public class Demo {
public static void main(String[] args) {
LuceneIndexUtil luceneUtil = LuceneIndexUtil.getInstance();
List articles = new ArrayList<>();
try {
//索引数据
ArticleModel article1 = new ArticleModel();
article1.setTitle(“J 《大厂前端面试题解析+Web核心总结学习笔记+企业项目实战源码+最新高清讲解视频》无偿开源 徽信搜索公众号【编程进阶路】 ava天下第一”);
article1.setAuthor(“粉丝”);
article1.setContent(“这是一篇给大家介绍 Lucene 的技术文章，必定点赞评论转发！！！”);
ArticleModel article2 = new ArticleModel();
article2.setTitle(“天下第一”);
article2.setAuthor(“粉丝”);
article2.setContent(“此处省略两千字…”);
ArticleModel article3 = new ArticleModel();
article3.setTitle(“Java天下第一”);
article3.setAuthor(“粉丝”);
article3.setContent(“Today is big day!”);
articles.add(article1);
articles.add(article2);
articles.add(article3);
luceneUtil.addModelDocs(articles);
luceneUtil.commit();

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

上面的 content 内容可以自行进行替换，小编这边避免凑字数的嫌疑就不贴了。

运行结束过后，我们用过 Lucene 的可视化工具 luke 来查看下索引的数据内容，下载过后解压我们可以看到有.bat 和 .sh 两个脚本，根据自己的系统进行运行就好了。小编这边是 mac 用的是 sh 脚本运行，运行后打开设置的索引目录即可。

进入过后，我们可以看到下图显示的内容，选择 content 点击 show top items 可以看到右侧的索引数据，这里根据分词器的不同，索引的结果是不一样的，小编这里采用的分词器就是标准的分词器，小伙伴们可以根据自己的要求选择适合自己的分词器即可。

数据已经索引成功了，接下来我们就需要根据条件进行数据的搜索了，我们创建一个 LuceneSearchUtil.java 来操作数据。

import org.apache.commons.collections.MapUtils;
import org.apache.lucene.analysis.Analyzer;
import org.apache.lucene.analysis.standard.StandardAnalyzer;
import org.apache.lucene.index.DirectoryReader;
import org.apache.lucene.queryparser.classic.QueryParser;
import org.apache.lucene.search.*;
import org.apache.lucene.store.Directory;
import org.apache.lucene.store.FSDirectory;
import org.springframework.beans.factory.annotation.Value;

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

public class LuceneSearchUtil {

private static String INDEX_PATH = “/opt/lucene/demo”;
private static IndexSearcher searcher;

public static LuceneSearchUtil getInstance() {
return LuceneSearchUtil.SingletonHolder.searchUtil;
}

private static class SingletonHolder {
public final static LuceneSearchUtil searchUtil = new LuceneSearchUtil();
}

private LuceneSearchUtil() {
this.initSearcher();
}

private void initSearcher() {
Directory directory;
try {
directory = FSDirectory.open(Paths.get(INDEX_PATH));
DirectoryReader reader = DirectoryReader.open(directory);
searcher = new IndexSearcher(reader);
} catch (IOException e) {
e.printStackTrace();
}
}

public TopDocs searchByMap(Map queryMap) throws Exception {
if (null == searcher) {
this.initSearcher();
}
if (MapUtils.isNotEmpty(queryMap)) {
BooleanQuery.Builder builder = new BooleanQuery.Builder();
queryMap.forEach((key, value) -> {
if (value instanceof String) {
Query queryString = new PhraseQuery(key, (String) value);
// Query queryString = new TermQuery(new Term(key, (String) value));
builder.add(queryString, BooleanClause.Occur.MUST);
}
});
return searcher.search(builder.build(), 10);
}
return null;
}

}

在 demo.java 中增加搜索代码如下：

//查询数据
Map map = new HashMap<>();
map.put(“title”, “Java 天下第一”);
// map.put(“title”, “天下第一”);
// map.put(“content”, “最”);
LuceneSearchUtil searchUtil = LuceneSearchUtil.getInstance();
TopDocs topDocs = searchUtil.searchByMap(map);
System.out.println(topDocs.totalHits);

map.put(“title”, “Java 天下第一”);
// map.put(“title”, “天下第一”);
// map.put(“content”, “最”);
LuceneSearchUtil searchUtil = LuceneSearchUtil.getInstance();
TopDocs topDocs = searchUtil.searchByMap(map);
System.out.println(topDocs.totalHits);