下面演示的是Lucene-3.6.2中针对搜索结果进行排序的各种效果（详见代码注释）
package com.jadyer.lucene;
import java.io.File;
import java.io.IOException;
import java.text.SimpleDateFormat;
import java.util.Date;
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.IndexReader;
import org.apache.lucene.index.IndexWriter;
import org.apache.lucene.index.IndexWriterConfig;
import org.apache.lucene.queryParser.QueryParser;
import org.apache.lucene.search.IndexSearcher;
import org.apache.lucene.search.ScoreDoc;
import org.apache.lucene.search.Sort;
import org.apache.lucene.search.SortField;
import org.apache.lucene.search.TopDocs;
import org.apache.lucene.store.Directory;
import org.apache.lucene.store.FSDirectory;
import org.apache.lucene.util.Version;
/**
* Lucene系列第06节之高级搜索之排序
* Created by 玄玉<https://jadyer.cn/> on 2013/08/19 11:04.
*/
public class AdvancedSearchBySort {
private Directory directory;
private IndexReader reader;
public AdvancedSearchBySort(){
/** 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"};
/** 文件日期 */
Date[] dates = new Date[sizes.length];
SimpleDateFormat sdf = new SimpleDateFormat("yyyyMMdd HH:mm:ss");
IndexWriter writer = null;
Document doc = null;
try {
dates[0] = sdf.parse("20130407 15:25:30");
dates[1] = sdf.parse("20130407 16:30:45");
dates[2] = sdf.parse("20130213 11:15:25");
dates[3] = sdf.parse("20130808 09:30:55");
dates[4] = sdf.parse("20130526 13:54:22");
dates[5] = sdf.parse("20130701 17:35:34");
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));
doc.add(new NumericField("date", Field.Store.YES, true).setLongValue(dates[i].getTime()));
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
}
/**
* 搜索排序
* ----------------------------------------------------------------------------------------------------------------
* 关于Sort参数的可输入规则，如下所示
* 1)Sort.INDEXORDER--使用文档编号从小到大的顺序进行排序
* 2)Sort.RELEVANCE---使用文档评分从大到小的顺序进行排序，也是默认的排序规则，等价于search(query, 10)
* 3)new Sort(new SortField("size", SortField.INT))-----------使用文件大小从小到大的顺序排序
* 4)new Sort(new SortField("date", SortField.LONG))----------使用文件日期从以前到现在的顺序排序
* 5)new Sort(new SortField("name", SortField.STRING))--------使用文件名从A到Z的顺序排序
* 6)new Sort(new SortField("name", SortField.STRING, true))--使用文件名从Z到A的顺序排序
* 7)new Sort(new SortField("size", SortField.INT), SortField.FIELD_SCORE)--先按文件大小排，再按文档评分排（可指定多个排序规则）
* 注意:以上7个Sort再打印文档评分时都是NaN，只有search(query, 10)才会正确打印文档评分
* ----------------------------------------------------------------------------------------------------------------
* @param expr 搜索表达式
* @param sort 排序规则
*/
public void searchBySort(String expr, Sort sort){
IndexSearcher searcher = new IndexSearcher(this.getIndexReader());
QueryParser parser = new QueryParser(Version.LUCENE_36, "content", new StandardAnalyzer(Version.LUCENE_36));
TopDocs tds = null;
try {
if(null == sort){
tds = searcher.search(parser.parse(expr), 10);
}else{
tds = searcher.search(parser.parse(expr), 10, sort);
}
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.print("size=" + doc.get("size") + " date=");
System.out.print(new SimpleDateFormat("yyyyMMdd HH:mm:ss").format(new Date(Long.parseLong(doc.get("date")))));
System.out.println(" name=" + doc.get("name"));
}
} catch (Exception e) {
e.printStackTrace();
} finally {
if(searcher != null){
try {
searcher.close();
} catch (IOException e) {
e.printStackTrace();
}
}
}
}
/**
* 测试一下排序效果
*/
public static void main(String[] args) {
AdvancedSearchBySort advancedSearch = new AdvancedSearchBySort();
////使用文档评分从大到小的顺序进行排序,也是默认的排序规则
//advancedSearch.searchBySort("Java", null);
//advancedSearch.searchBySort("Java", Sort.RELEVANCE);
////使用文档编号从小到大的顺序进行排序
//advancedSearch.searchBySort("Java", Sort.INDEXORDER);
////使用文件大小从小到大的顺序排序
//advancedSearch.searchBySort("Java", new Sort(new SortField("size", SortField.INT)));
////使用文件日期从以前到现在的顺序排序
//advancedSearch.searchBySort("Java", new Sort(new SortField("date", SortField.LONG)));
////使用文件名从A到Z的顺序排序
//advancedSearch.searchBySort("Java", new Sort(new SortField("name", SortField.STRING)));
////使用文件名从Z到A的顺序排序
//advancedSearch.searchBySort("Java", new Sort(new SortField("name", SortField.STRING, true)));
//先按照文件大小排序,再按照文档评分排序(可以指定多个排序规则)
advancedSearch.searchBySort("Java", new Sort(new SortField("size", SortField.INT), SortField.FIELD_SCORE));
}
}