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11、学习Lucene3.5索引搜索之分页显示

方法一:将所有的结果搜索出来,再进行分页

public void searchPage(String queryCondition, int pageIndex, int pageSize){
IndexReader indexReader = null;
try {
Directory directory = FileIndexUtil.getDirectory();
indexReader = IndexReader.open(directory);
IndexSearcher indexSearcher = new IndexSearcher(indexReader);
QueryParser queryParser = new QueryParser(Version.LUCENE_35, "content",
new StandardAnalyzer(Version.LUCENE_35));
Query query = queryParser.parse(queryCondition);
TopDocs topDocs = indexSearcher.search(query, 100);
ScoreDoc[] scoreDocs = topDocs.scoreDocs;
int start = (pageIndex - 1) * pageSize;
int end = pageIndex * pageSize;
if (scoreDocs != null && scoreDocs.length>0){
for (int i = start-1; i < end; i++){
Document document = indexSearcher.doc(scoreDocs[i].doc);
System.out.println("filename: "+document.get("filename")+"---->"+" size: "+document.get("size"));
}
}
indexReader.close();
} catch (ParseException e) {
e.printStackTrace();
} catch (IOException e) {
e.printStackTrace();
}
}


方法二:利用“searchAfter()”只搜索部分数据,节约资源(注意:3.5之前没有)

/**
* 获取上一次搜索最后一项:
* 基本思路:将上一次的搜索数量进行限制(条件为最后一项为搜索数量上限),取出最后一项即为上一次搜索的最后一项
* 好处:避免每次都要将所有的索引项搜索出来,浪费资源
*/
private ScoreDoc getLastScoreDoc(IndexSearcher indexSearcher, Query query, int pageIndex, int pageSize) throws IOException, ParseException {
//若是第一页,就返回null(第一页的前一页没有)
if (pageIndex == 1){
return null;
}
/**
* 分析: 1 19 null 2 39 19
*/
int num = (pageIndex - 1)*pageSize;
TopDocs topDocs = indexSearcher.search(query, num);
ScoreDoc[] scoreDocs = topDocs.scoreDocs;
return scoreDocs[num-1];
}
/**
* 对搜索结果进行分页(第二种方式:只搜索部分数据)
*/
public void searchPageByAfter(String queryCondition, int pageIndex, int pageSize){
IndexReader indexReader = null;
try {
Directory directory = FileIndexUtil.getDirectory();
indexReader = IndexReader.open(directory);
IndexSearcher indexSearcher = new IndexSearcher(indexReader);
QueryParser queryParser = new QueryParser(Version.LUCENE_35, "content",
new StandardAnalyzer(Version.LUCENE_35));
Query query = queryParser.parse(queryCondition);

/**
* 获取上一次搜索最后一项
*/
ScoreDoc after = getLastScoreDoc(indexSearcher, query, pageIndex, pageSize);
/**
* 通过上一页的最后一个元素,获取下一页pageSize个元素
* TopDocs searchAfter(ScoreDoc after, Query query, int n)
* 参数一:上一次搜索最后一项
* 参数二:查询条件
* 参数三:查询数量
* 优点:避免每次搜索所有,浪费资源
*/
TopDocs topDocs = indexSearcher.searchAfter(after, query, pageSize);
ScoreDoc[] scoreDocs = topDocs.scoreDocs;
int start = (pageIndex - 1) * pageSize;
int end = pageIndex * pageSize;
if (scoreDocs != null && scoreDocs.length>0){
for (int i = start-1; i < end; i++){
Document document = indexSearcher.doc(scoreDocs[i].doc);
System.out.println("filename: "+document.get("filename")+"---->"+" size: "+document.get("size"));
}
}
indexReader.close();
} catch (ParseException e) {
e.printStackTrace();
} catch (IOException e) {
e.printStackTrace();
}
}


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