关于lucene搜索时排序的问题

在Lucene4.6中，想要实现搜索结果按照时间倒序的效果：如果两个文档得分相同，那么就按照发布时间倒序排列；否则就按照分数排列。这种效果在 Lucene4.6中实现起来极其简单，直接利用search接口的Sort参数即可达成，完全不需要像某些人说的重写Similarity那么麻烦。三 两行代码的事情，体现了Make it simple, stupid的精髓。

package com.hankcs.test;
import org.apache.lucene.analysis.Analyzer;
import org.apache.lucene.document.*;
import org.apache.lucene.index.*;
import org.apache.lucene.queries.CustomScoreQuery;
import org.apache.lucene.queries.function.FunctionQuery;
import org.apache.lucene.queryparser.classic.ParseException;
import org.apache.lucene.queryparser.classic.QueryParser;
import org.apache.lucene.search.*;
import org.apache.lucene.store.Directory;
import org.apache.lucene.store.LockObtainFailedException;
import org.apache.lucene.store.RAMDirectory;
import org.apache.lucene.util.Version;import org.wltea.analyzer.lucene.IKAnalyzer;
import java.io.IOException;
/** * @author hankcs */
public class TestSortByTime{
public static void main(String[] args)    {
// Lucene Document的主要域名
String fieldName = "text";
// 实例化IKAnalyzer分词器
Analyzer analyzer = new IKAnalyzer();
Directory directory = null;
IndexWriter iwriter;
IndexReader ireader = null;
IndexSearcher isearcher;
try        {
//索引过程**********************************
//建立内存索引对象
directory = new RAMDirectory();
//配置IndexWriterConfig
IndexWriterConfig iwConfig = new IndexWriterConfig(Version.LUCENE_46, analyzer);
iwConfig.setOpenMode(IndexWriterConfig.OpenMode.CREATE_OR_APPEND);
iwriter = new IndexWriter(directory, iwConfig);
//写入索引
for (int i = 0; i < 3; ++i) {
int year = 2004 + i;
Document doc = new Document();
doc.add(new TextField(fieldName, year + "全民突击攻略", Field.Store.YES));
doc.add(new IntField("date",  year * 10000 + 1111, Field.Store.YES));
iwriter.addDocument(doc);}
// 加入一个干扰文档
Document doc = new Document();
doc.add(new TextField(fieldName, "天天酷跑攻略", Field.Store.YES));
doc.add(new IntField("date",  20141111, Field.Store.YES));
iwriter.addDocument(doc);
iwriter.close();
//搜索过程**********************************
//实例化搜索器
ireader = DirectoryReader.open(directory);
isearcher = new IndexSearcher(ireader);
String keyword = "全民突击攻略";
//使用QueryParser查询分析器构造Query对象
QueryParser qp = new QueryParser(Version.LUCENE_46, fieldName, analyzer);
Query query = qp.parse(keyword);
System.out.println("Query = " + query);
//搜索相似度最高的5条记录
Sort sort = new Sort(new SortField("text", SortField.Type.SCORE), new SortField("date", SortField.Type.INT, true));            To
pDocs topDocs = isearcher.search(query, 5, sort);
System.out.println("命中：" + topDocs.totalHits);
//输出结果
ScoreDoc[] scoreDocs = topDocs.scoreDocs;
for (int i = 0; i < Math.min(5, scoreDocs.length); i++){
Document targetDoc = isearcher.doc(scoreDocs[i].doc);
System.out.print(targetDoc.getField(fieldName).stringValue());
System.out.print(" , " + targetDoc.getField("date").numericValue());
System.out.println(" , " + scoreDocs[i].score);            }
} catch (CorruptIndexException e)        {
e.printStackTrace();
} catch (LockObtainFailedException e)        {
e.printStackTrace();
} catch (IOException e){           &nb
3ff0
sp;
e.printStackTrace();
} catch (ParseException e)        {
e.printStackTrace();
} finally        {
if (ireader != null)  {
try{
ireader.close();
} catch (IOException e)                {
e.printStackTrace();                }
}
if (directory != null)            {
try                {
directory.close();
} catch (IOException e)                {
e.printStackTrace();                }
}        }    }}