下面演示的是Lucene-3.6.2中搜索的时候，自定义评分的用法（详见代码注释）
package com.jadyer.lucene;
import java.io.File;
import java.io.IOException;
import java.util.Random;
import org.apache.lucene.analysis.standard.StandardAnalyzer;
import org.apache.lucene.document.Document;
import org.apache.lucene.document.Field;
import org.apache.lucene.document.NumericField;
import org.apache.lucene.index.CorruptIndexException;
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.apache.lucene.util.Version;
import com.jadyer.custom.MyNameScoreQuery;
/**
* Lucene系列第08节之高级搜索之评分
* Created by 玄玉<https://jadyer.cn/> on 2013/08/19 12:13.
*/
public class AdvancedSearchByScore {
private Directory directory;
private IndexReader reader;
public AdvancedSearchByScore(){
/** 文件大小 */
int[] sizes = {90, 10, 20, 10, 60, 50};
/** 文件名 */
String[] names = {"Michael.java", "Scofield.ini", "Tbag.txt", "Jack", "Jade", "Jadyer"};
/** 文件内容 */
String[] contents = {"my blog is https://jadyer.cn/",
"my github is https://github.com/jadyer",
"my name is jadyer",
"I am a Java Developer",
"I am from Haerbin",
"I like java of Lucene"};
IndexWriter writer = null;
Document doc = null;
try {
directory = FSDirectory.open(new File("myExample/01_index/"));
writer = new IndexWriter(directory, new IndexWriterConfig(Version.LUCENE_36, new StandardAnalyzer(Version.LUCENE_36)));
writer.deleteAll();
for(int i=0; i<sizes.length; i++){
doc = new Document();
doc.add(new NumericField("size", Field.Store.YES, true).setIntValue(sizes[i]));
doc.add(new Field("name", names[i], Field.Store.YES, Field.Index.ANALYZED_NO_NORMS));
doc.add(new Field("content", contents[i], Field.Store.NO, Field.Index.ANALYZED));
//添加一个评分域，专门在自定义评分时使用（此时默认为Field.Store.NO和Field.Index.ANALYZED_NO_NORMS）
doc.add(new NumericField("fileScore").setIntValue(new Random().nextInt(600)));
writer.addDocument(doc);
}
} catch (Exception e) {
e.printStackTrace();
} finally {
if(null != writer){
try {
writer.close();
} catch (IOException ce) {
ce.printStackTrace();
}
}
}
}
/**
* 获取IndexReader实例
*/
private IndexReader getIndexReader(){
try {
if(reader == null){
reader = IndexReader.open(directory);
}else{
//if the index was changed since the provided reader was opened, open and return a new reader; else,return null
//如果当前reader在打开期间index发生改变，则打开并返回一个新的IndexReader，否则返回null
IndexReader ir = IndexReader.openIfChanged(reader);
if(ir != null){
reader.close(); //关闭原reader
reader = ir; //赋予新reader
}
}
return reader;
}catch(Exception e) {
e.printStackTrace();
}
return null; //发生异常则返回null
}
/**
* 自定义评分搜索
*/
public void searchByCustomScoreQuery(){
IndexSearcher searcher = new IndexSearcher(this.getIndexReader());
////创建一个评分域
//FieldScoreQuery fsq = new FieldScoreQuery("fileScore", FieldScoreQuery.Type.INT);
////创建自定义的CustomScoreQuery对象
//Query query = new MyCustomScoreQuery(new TermQuery(new Term("content", "java")), fsq);
Query query = new MyNameScoreQuery(new TermQuery(new Term("content", "java")));
try {
TopDocs tds = searcher.search(query, 10);
for(ScoreDoc sd : tds.scoreDocs){
Document doc = searcher.doc(sd.doc);
System.out.print("文档编号=" + sd.doc + " 文档权值=" + doc.getBoost() + " 文档评分=" + sd.score + " ");
System.out.println("size=" + doc.get("size") + " name=" + doc.get("name"));
}
} catch (CorruptIndexException e) {
e.printStackTrace();
} catch (IOException e) {
e.printStackTrace();
} finally {
if(searcher != null){
try {
searcher.close();
} catch (IOException e) {
e.printStackTrace();
}
}
}
}
/**
* 测试一下评分效果
*/
public static void main(String[] args) {
new AdvancedSearchByScore().searchByCustomScoreQuery();
}
}
下面是我们自定义的评分类MyCustomScoreQuery.java
package com.jadyer.custom;
import java.io.IOException;
import org.apache.lucene.index.IndexReader;
import org.apache.lucene.search.Query;
import org.apache.lucene.search.function.CustomScoreProvider;
import org.apache.lucene.search.function.CustomScoreQuery;
import org.apache.lucene.search.function.ValueSourceQuery;
/**
* 自定义评分的步骤
* ---------------------------------------------------------------------------------------
* 1)创建一个类继承于CustomScoreQuery
* 2)覆盖CustomScoreQuery.getCustomScoreProvider()方法
* 3)创建一个类继承于CustomScoreProvider
* 4)覆盖CustomScoreProvider.customScore()方法：我们的自定义评分主要就是在此方法中完成的
* ---------------------------------------------------------------------------------------
* Created by 玄玉<https://jadyer.cn/> on 2013/08/06 10:30.
*/
public class MyCustomScoreQuery extends CustomScoreQuery {
private static final long serialVersionUID = -2373017691291184609L;
public MyCustomScoreQuery(Query subQuery, ValueSourceQuery valSrcQuery) {
//ValueSourceQuery参数就是指专门用来做评分的Query，即评分域的FieldScoreQuery
super(subQuery, valSrcQuery);
}
@Override
protected CustomScoreProvider getCustomScoreProvider(IndexReader reader) throws IOException {
//如果直接返回super的，就表示使用原有的评分规则，即通过[原有的评分*传入的评分域所获取的评分]来确定最终评分
//return super.getCustomScoreProvider(reader);
return new MyCustomScoreProvider(reader);
}
private class MyCustomScoreProvider extends CustomScoreProvider {
public MyCustomScoreProvider(IndexReader reader) {
super(reader);
}
@Override
public float customScore(int doc, float subQueryScore, float valSrcScore) throws IOException {
//subQueryScore--表示默认文档的打分，valSrcScore--表示评分域的打分
//该方法的返回值就是文档评分，即ScoreDoc.score获取的结果
System.out.println("subQueryScore=" + subQueryScore + " valSrcScore=" + valSrcScore);
return subQueryScore/valSrcScore;
}
}
}
下面是自定义的采用特殊文件名作为评分标准的评分类MyNameScoreQuery.java
package com.jadyer.custom;
import java.io.IOException;
import org.apache.lucene.index.IndexReader;
import org.apache.lucene.search.FieldCache;
import org.apache.lucene.search.Query;
import org.apache.lucene.search.function.CustomScoreProvider;
import org.apache.lucene.search.function.CustomScoreQuery;
/**
* 采用特殊文件名作为评分标准的评分类
* Created by 玄玉<https://jadyer.cn/> on 2013/08/06 14:17.
*/
public class MyNameScoreQuery extends CustomScoreQuery {
private static final long serialVersionUID = -2813985445544972520L;
public MyNameScoreQuery(Query subQuery) {
//由于这里是打算根据文件名来自定义评分，所以重写构造方法时不必传入评分域的ValueSourceQuery
super(subQuery);
}
@Override
protected CustomScoreProvider getCustomScoreProvider(IndexReader reader) throws IOException {
return new FilenameScoreProvider(reader);
}
private class FilenameScoreProvider extends CustomScoreProvider {
String[] filenames;
public FilenameScoreProvider(IndexReader reader) {
super(reader);
try {
//在IndexReader没有关闭之前，所有的数据都会存储到一个预缓存中（缺点是占用大量内存）
//所以我们可以通过预缓存获取name域的值（获取到的是name域所有值，故使用数组）
this.filenames = FieldCache.DEFAULT.getStrings(reader, "name");
} catch (IOException e) {
e.printStackTrace();
}
}
@Override
public float customScore(int doc, float subQueryScore, float valSrcScore) throws IOException {
//由于FilenameScoreQuery构造方法没有传入ValueSourceQuery，故此处ValueSourceQuery默认为1.0
System.out.println("subQueryScore=" + subQueryScore + " valSrcScore=" + valSrcScore);
if(filenames[doc].endsWith(".java") || filenames[doc].endsWith(".ini")){
//只加大java文件和ini文件的评分
return subQueryScore*1.5f;
}else{
return subQueryScore/1.5f;
}
}
}
}