搜索引擎的构建分为索引内容和查询索引两个大方面，这里要介绍的是lucene索引查询器即IndexSearcher的构建过程；
首先了解下IndexSearcher：
DirectoryReader.open(IndexWriter, boolean)）IndexSearcher实例是完全线程安全的,这意味着多个线程可以并发调用任何方法。如果需要外部同步,无需添加IndexSearcher的同步；
以下是根据IndexSearcher相关的构建过程及其特性编写的一个搜索的工具类
package com.lucene.search;
import java.io.File;
import java.io.IOException;
import java.nio.file.Paths;
import java.util.concurrent.ExecutorService;
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.index.MultiReader;
import org.apache.lucene.index.Term;
import org.apache.lucene.search.BooleanClause.Occur;
import org.apache.lucene.search.BooleanQuery;
import org.apache.lucene.search.IndexSearcher;
import org.apache.lucene.search.MatchAllDocsQuery;
import org.apache.lucene.search.NumericRangeQuery;
import org.apache.lucene.search.Query;
import org.apache.lucene.search.ScoreDoc;
import org.apache.lucene.search.Sort;
import org.apache.lucene.search.SortField;
import org.apache.lucene.search.SortField.Type;
import org.apache.lucene.search.TermQuery;
import org.apache.lucene.search.TopDocs;
import org.apache.lucene.search.TopFieldCollector;
import org.apache.lucene.store.FSDirectory;
import com.lucene.index.IndexUtil;
public class SearchUtil {
public static final Analyzer analyzer = new StandardAnalyzer();
/**获取IndexSearcher对象（适合单索引目录查询使用）
* @param indexPath 索引目录
* @return
* @throws IOException
* @throws InterruptedException
*/
public static IndexSearcher getIndexSearcher(String indexPath,ExecutorService service,boolean realtime) throws IOException, InterruptedException{
DirectoryReader reader = DirectoryReader.open(IndexUtil.getIndexWriter(indexPath, true), realtime);
IndexSearcher searcher = new IndexSearcher(reader,service);
if(service != null){
service.shutdown();
}
return searcher;
}
/**多目录多线程查询
* @param parentPath 父级索引目录
* @param service 多线程查询
* @return
* @throws IOException
* @throws InterruptedException
*/
public static IndexSearcher getMultiSearcher(String parentPath,ExecutorService service,boolean realtime) throws IOException, InterruptedException{
MultiReader multiReader;
File file = new File(parentPath);
File[] files = file.listFiles();
IndexReader[] readers = new IndexReader[files.length];
if(!realtime){
for (int i = 0 ; i < files.length ; i ++) {
readers[i] = DirectoryReader.open(FSDirectory.open(Paths.get(files[i].getPath(), new String[0])));
}
}else{
for (int i = 0 ; i < files.length ; i ++) {
readers[i] = DirectoryReader.open(IndexUtil.getIndexWriter(files[i].getPath(), true), true);
}
}
multiReader = new MultiReader(readers);
IndexSearcher searcher = new IndexSearcher(multiReader,service);
if(service != null){
service.shutdown();
}
return searcher;
}
/**从指定配置项中查询
* @return
* @param analyzer 分词器
* @param field 字段
* @param fieldType 字段类型
* @param queryStr 查询条件
* @param range 是否区间查询
* @return
*/
public static Query getQuery(String field,String fieldType,String queryStr,boolean range){
Query q = null;
if(queryStr != null && !"".equals(queryStr)){
if(range){
String[] strs = queryStr.split("\\|");
if("int".equals(fieldType)){
int min = new Integer(strs[0]);
int max = new Integer(strs[1]);
q = NumericRangeQuery.newIntRange(field, min, max, true, true);
}else if("double".equals(fieldType)){
Double min = new Double(strs[0]);
Double max = new Double(strs[1]);
q = NumericRangeQuery.newDoubleRange(field, min, max, true, true);
}else if("float".equals(fieldType)){
Float min = new Float(strs[0]);
Float max = new Float(strs[1]);
q = NumericRangeQuery.newFloatRange(field, min, max, true, true);
}else if("long".equals(fieldType)){
Long min = new Long(strs[0]);
Long max = new Long(strs[1]);
q = NumericRangeQuery.newLongRange(field, min, max, true, true);
}
}else{
if("int".equals(fieldType)){
q = NumericRangeQuery.newIntRange(field, new Integer(queryStr), new Integer(queryStr), true, true);
}else if("double".equals(fieldType)){
q = NumericRangeQuery.newDoubleRange(field, new Double(queryStr), new Double(queryStr), true, true);
}else if("float".equals(fieldType)){
q = NumericRangeQuery.newFloatRange(field, new Float(queryStr), new Float(queryStr), true, true);
}else{
Term term = new Term(field, queryStr);
q = new TermQuery(term);
}
}
}else{
q= new MatchAllDocsQuery();
}
System.out.println(q);
return q;
}
/**多条件查询类似于sql in
* @param querys
* @return
*/
public static Query getMultiQueryLikeSqlIn(Query ... querys){
BooleanQuery query = new BooleanQuery();
for (Query subQuery : querys) {
query.add(subQuery,Occur.SHOULD);
}
return query;
}
/**多条件查询类似于sql and
* @param querys
* @return
*/
public static Query getMultiQueryLikeSqlAnd(Query ... querys){
BooleanQuery query = new BooleanQuery();
for (Query subQuery : querys) {
query.add(subQuery,Occur.MUST);
}
return query;
}
/**对多个条件进行排序构建排序条件
* @param fields
* @param type
* @param reverses
* @return
*/
public static Sort getSortInfo(String[] fields,Type[] types,boolean[] reverses){
SortField[] sortFields = null;
int fieldLength = fields.length;
int typeLength = types.length;
int reverLength = reverses.length;
if(!(fieldLength == typeLength) || !(fieldLength == reverLength)){
return null;
}else{
sortFields = new SortField[fields.length];
for (int i = 0; i < fields.length; i++) {
sortFields[i] = new SortField(fields[i], types[i], reverses[i]);
}
}
return new Sort(sortFields);
}
/**根据查询器、查询条件、每页数、排序条件进行查询
* @param query 查询条件
* @param first 起始值
* @param max 最大值
* @param sort 排序条件
* @return
*/
public static TopDocs getScoreDocsByPerPageAndSortField(IndexSearcher searcher,Query query, int first,int max, Sort sort){
try {
if(query == null){
System.out.println(" Query is null return null ");
return null;
}
TopFieldCollector collector = null;
if(sort != null){
collector = TopFieldCollector.create(sort, first+max, false, false, false);
}else{
sort = new Sort(new SortField[]{new SortField("modified", SortField.Type.LONG)});
collector = TopFieldCollector.create(sort, first+max, false, false, false);
}
searcher.search(query, collector);
return collector.topDocs(first, max);
} catch (IOException e) {
// TODO Auto-generated catch block
}
return null;
}
/**获取上次索引的id,增量更新使用
* @return
*/
public static Integer getLastIndexBeanID(IndexReader multiReader){
Query query = new MatchAllDocsQuery();
IndexSearcher searcher = null;
searcher = new IndexSearcher(multiReader);
SortField sortField = new SortField("id", SortField.Type.INT,true);
Sort sort = new Sort(new SortField[]{sortField});
TopDocs docs = getScoreDocsByPerPageAndSortField(searcher,query, 0, 1, sort);
ScoreDoc[] scoreDocs = docs.scoreDocs;
int total = scoreDocs.length;
if(total > 0){
ScoreDoc scoreDoc = scoreDocs[0];
Document doc = null;
try {
doc = searcher.doc(scoreDoc.doc);
} catch (IOException e) {
// TODO Auto-generated catch block
e.printStackTrace();
}
return new Integer(doc.get("id"));
}
return 0;
}
}
以上即是lucene搜索之IndexSearcher构建过程相关内容；
相关代码下载明天会给出相关链接
一步一步跟我学习lucene是对近期做lucene索引的总结，大家有问题的话联系本人的Q-Q: 891922381，同时本人新建Q-Q群：106570134（lucene,solr,netty,hadoop），如蒙加入，不胜感激，大家共同探讨,本人争取每日一博，希望大家持续关注，会带给大家惊喜的
一步一步跟我学习lucene（7）---lucene搜索之IndexSearcher构建过程
原文地址：http://blog.csdn.net/wuyinggui10000/article/details/45698667
