lucene使用教程4 --常用类的对象之IndexSearcher

这章主要介绍IndexSearcher

IndexSearcher，一个我们用来搜索IndexWriter创建的索引的命令行程序。(记住我们的Seacher只是用来示范Lucene的搜索API的用法。你的搜索程序也可以是网页或带有GUI的桌面程序或EJB等形式。)

一下代码是从网上剪切过来的，可能有错误，但是原理都是一样的，明白了原理，什么都简单。稍后我会将我自己写的几个测试代码贴上去，可以 关注下后面的文字

MyIndexSearcher对IndexSearcher的创建和回收：

public class MyIndexSearcher {
	private static IndexSearcher indexSearcher;
	private static IndexReader indexReader;
	private static ArrayList<Thread> threadList = new ArrayList<Thread>();
	private static Directory dir = null;
	private MyIndexSearcher() {
	}

	/**
	 * 
	 * @function 创建IndexSearcher对象
	 * @param indexFilePath 索引路径
	 * @return
	 */
	public static IndexSearcher getInstance(String indexFilePath) {
		synchronized (threadList) {
			if (indexSearcher == null) {
				File indexFile = new File(indexFilePath);
				try {
					if (!indexFile.exists()) {
						indexFile.mkdirs();
					}
					dir = FSDirectory.open(indexFile);
					// 读取索引的indexReader
					indexReader = IndexReader.open(dir);
					// 创建indexSearcher
					indexSearcher = new IndexSearcher(indexReader);

				} catch (IOException e) {
					e.printStackTrace();
				} finally {
					indexFile=null;
				}
			}
			if (!threadList.contains(Thread.currentThread()))
				threadList.add(Thread.currentThread());
			return indexSearcher;
		}
	}
	/**
	 * 
	 * @function 关闭IndexSearcher对象
	 */
	public static void close() {
		synchronized (threadList) {
			if (threadList.contains(Thread.currentThread()))
				threadList.remove(Thread.currentThread());

			if (threadList.size() == 0) {
				try {
					if (indexReader != null) {
						indexReader.close();
						indexReader = null;
					}
					if (indexSearcher != null) {
						indexSearcher.close();
						indexSearcher = null;
					}
					if (dir != null) {
						dir.close();
					}
				} catch (IOException e) {
					e.printStackTrace();
				}
			}
		}
	}
}

使用IndexSearcher搜索索引

IndexSearcher用来搜索而IndexWriter用来索引：暴露几个搜索方法的索引的主要链接。你可以把IndexSearcher想象为以只读方式打开索引的一个类。它提供几个搜索方法，其中一些在抽象基类IndexSearcher中实现；最简单的接受单个Query对象做为参数并返回一个Hits对象。

/**
	 * 
	 * @function 查询所有资源
	 * @param searchParam
	 *            查询内容关键字
	 * @param pageNum 页码
	 * @param pageSize 每页显示大小
	 * @return
	 */
	public static List<SearchBean> getSearchBeanAll(String searchParam,
			int pageNum, int pageSize) throws Exception {
		// 庖丁解牛分词器
		Analyzer analyzer = new PaodingAnalyzer();
		// 对用户的输入进行查询
		searcher = MyIndexSearcher.getInstance(FILE_PATH
				+ ConfigurationManager.getInstance().getPropertiesValue(
						"common.properties", "AllIndexFilePath") + "/index");

		// 对用户的输入进行查询
		Query query = MultiFieldQueryParser.parse(Version.LUCENE_CURRENT,
				searchParam, new String[] { "title", "content", "url",
						"keyword", "time" }, new BooleanClause.Occur[] {
						BooleanClause.Occur.SHOULD, BooleanClause.Occur.SHOULD,
						BooleanClause.Occur.SHOULD, BooleanClause.Occur.SHOULD,
						BooleanClause.Occur.SHOULD }, analyzer);
		BooleanQuery bQuery = new BooleanQuery();
		bQuery.add(query, BooleanClause.Occur.MUST);
		// 根据字段进行排序，得到查询结果
		SortField sortField1 = new SortField("time", SortField.STRING, true);// false代表升序，TRUE代表降序
		SortField sortField2 = new SortField("keyword", SortField.SCORE, false);
		SortField sortField3 = new SortField("title", SortField.SCORE, false);

		TopDocs topDocs = searcher.search(bQuery, null, 100000, new Sort(
				sortField3, sortField2, sortField1));
		List<SearchBean> list = getSearchResult(analyzer, topDocs, bQuery,
				searchParam, pageNum, pageSize);
		// for (SearchBean searchBean : list) {
		// System.out.println(searchBean.toString());
		// }
		return list;
	}

	/**
	 * 
	 * @function 得到查询结果
	 * @param analyzer 分词器
	 * @param topDocs 搜索文档
	 * @param query 搜索对象
	 * @param searchParam 搜索内容关键字
	 * @param pageNum 页码
	 * @param pageSize 页显示数
	 * @return
	 */
	public static List<SearchBean> getSearchResult(Analyzer analyzer,
			TopDocs topDocs, Query query, String searchParam, int pageNum,
			int pageSize) throws Exception {

		FastVectorHighlighter highlighter = getHighlighter();
		FieldQuery fieldQuery = highlighter.getFieldQuery(query);
		ScoreDoc[] scoreDocs = topDocs.scoreDocs;
		// 查询结果数量
		num = topDocs.totalHits;
		// 创建list，将结果保存其中，以便在jsp页面中进行显示
		List<SearchBean> list = new ArrayList<SearchBean>();
		// 模拟hibernate的serFirstResult和setMaxResult以便返回指定条目的结果
		int end = 0;
		int begin = 0;
		begin = pageSize * (pageNum - 1);
		if (begin > num) {
			begin = begin - pageSize + num % pageSize;
		}
		if (pageNum * pageSize > num) {
			end = num;
		} else
			end = pageNum * pageSize;
		// System.out.println(num + "/" + begin + "/" + end);
		try {
			for (int i = begin; i < end; i++) {

				String bestFragmentTitle = highlighter.getBestFragment(
						fieldQuery, searcher.getIndexReader(),
						scoreDocs[i].doc, "title", 50);

				String bestFragmentContent = highlighter.getBestFragment(
						fieldQuery, searcher.getIndexReader(),
						scoreDocs[i].doc, "content", 100);
			
				String bestFragmentKeyword = highlighter.getBestFragment(
						fieldQuery, searcher.getIndexReader(),
						scoreDocs[i].doc, "keyword", 100);
				String bestFragmentTime = highlighter.getBestFragment(
						fieldQuery, searcher.getIndexReader(),
						scoreDocs[i].doc, "time", 100);
				Document doc = searcher.doc(scoreDocs[i].doc);
				// 取得该条索引文档
				SearchBean sb = new SearchBean();
				String id = doc.get("id");
				String title = doc.get("title");
				String content = doc.get("content");
				String url = doc.get("url");
				String keyword = doc.get("keyword");
				String time = doc.get("time");
				String author = doc.get("author");
				String module = doc.get("module");
				String type = doc.get("type");
				sb.setId(id);
				sb.setTitle((bestFragmentTitle != null && bestFragmentTitle != "") ? bestFragmentTitle: title);
				sb.setContent((bestFragmentContent != null && bestFragmentContent != "") ? bestFragmentContent: content);
				sb.setUrl(url);
				sb.setKeyword((bestFragmentKeyword != null && bestFragmentKeyword != "") ? bestFragmentKeyword: keyword);
				sb.setTime((bestFragmentTime != null && bestFragmentTime != "") ? bestFragmentTime: time);
				sb.setAuthor(author);
				sb.setModule(module);
				sb.setType(type); 
				list.add(sb);
			}
		} catch (Exception e) {
			e.printStackTrace();
			logger.error(e.getMessage());
		} finally {
			MyIndexSearcher.close();
		}
		return list;
	}