[size=large][/size]最近在学习lucene搜索开源库,看一些书,比如《lucene in action》就是比较注重实战的,书里面基本将lucene涉及的操作基本涵盖,但是有些地方却只是点了一下,个人水平有限,而且只是写了一个小项目,有些感受:
1. 语汇单元到二进制文件的算法,其中关系到下面的索引结构
2.索引文件结构,在抽象概念上单词词典和倒排例表,具体到文件,就是叫做倒排索引,至于前面两个概念,单词词典:将field中term(最小基本单元)存储,一般是由单词,频率,指向包含单词文档的指针(指向到排列表中与term有关的doc位置),一般是以B+树形式;倒排列表则是存储DOCID,逆文档频率,具体单词在文档中的位置信息,一般形式(三元组)
单词(你好,2,*p)--->(文档1,5,(2,4,7,8,13)->(文档2,3(5,9,12))
单词(第,2,*p)--->(文档1,,5,(1,6,9,15)->(文档2,3(51,81,121))
单词(分布筋,2,*p)--->(文档1,5,(3,14,35,36,37)->(文档2,3(52,82,122))
{单词你好出现在文档1,2,对应频率5,3,出现位置分别为2,4,7,8,13;5,,9,12}
3.indexwriter到tokenstream的构建思路,tokenstream中increamentoken方法和analyzer形成语汇单元时的调用(我看了一下源码,在高级的类里面,并没有看到analyzer.tokenstream方法,形成语汇单元时调用increamentoken来语汇单元进行处理,但是在底层接口和抽象积累里面有大量attribute属性,估计通过映射获取,直接获取处理),这一方面涉及比较多算法和数据结构,而且就算根据反射获取,也不是很清楚算法实现过程
4.查询过程中只讲了查询器,过滤器使用和构建简单的,但是本质上是一样的,看了那个过滤器与查询器相互转换的转换器,constantScoreQuery,QuerywrapperFilter,是类似于filter与query之间的转换,有点强制转换的意味,我没有理解深 另外对于其分析查询过程,基本没有,其它书也没怎么讲,但是在搜索引擎里面,就比较多,查询短语,lucene,phrasequery,但是实现上有一些方式:单独建立短语索引,扩展倒排列表,双词查询
5.评分机制,直说payload,直接切入二进制,干扰评分的,通过payloadhelper,这个可对关键词进行一定的加权
6.实际用于比较多的扩张功能:热备份,高亮显示,使用数据库引擎berkely,公取索引,提示列表
总结一下我们学习lucene初步知识:
各种查询器混合使用,过滤器适合的时候使用;索引合并以及热备份;与数据库引擎的联合使用:比如berkely;对文本的解析成文本文件,可以使用tika,如果不相适应解析器,可以使用pdfbox类似的中间解析器来使用,简单一些但是就繁琐了一定;对于搜索方面的人性化定制,高亮显示以及提示,根据用户词语获取用户可能希望的词汇
以及相关搜索方面的知识:
下面关于kucene使用的一个class,以上关于lucene涉及的操作基本都有
package search; import java.io.BufferedInputStream; import java.io.BufferedOutputStream; import java.io.File; import java.io.FileInputStream; import java.io.FileOutputStream; import java.io.FileWriter; import java.io.IOException; import java.io.StringReader; import java.text.SimpleDateFormat; import java.util.Calendar; import java.util.Collection; import java.util.Date; import java.util.Iterator; import java.util.concurrent.CopyOnWriteArrayList; import org.apache.lucene.analysis.SimpleAnalyzer; import org.apache.lucene.analysis.TokenStream; import org.apache.lucene.analysis.cn.smart.SmartChineseAnalyzer; import org.apache.lucene.document.Document; import org.apache.lucene.document.Field; import org.apache.lucene.document.FieldSelector; import org.apache.lucene.document.MapFieldSelector; import org.apache.lucene.index.CorruptIndexException; import org.apache.lucene.index.FieldSortedTermVectorMapper; import org.apache.lucene.index.IndexCommit; import org.apache.lucene.index.IndexDeletionPolicy; import org.apache.lucene.index.IndexReader; import org.apache.lucene.index.IndexWriter; import org.apache.lucene.index.KeepOnlyLastCommitDeletionPolicy; import org.apache.lucene.index.SnapshotDeletionPolicy; import org.apache.lucene.index.Term; import org.apache.lucene.queryParser.ParseException; import org.apache.lucene.queryParser.QueryParser; import org.apache.lucene.search.BooleanClause.Occur; import org.apache.lucene.search.highlight.Highlighter; import org.apache.lucene.search.highlight.InvalidTokenOffsetsException; import org.apache.lucene.search.highlight.QueryScorer; import org.apache.lucene.search.highlight.SimpleSpanFragmenter; import org.apache.lucene.search.spell.LuceneDictionary; import org.apache.lucene.search.spell.SpellChecker; import org.apache.lucene.search.BooleanQuery; import org.apache.lucene.search.Collector; import org.apache.lucene.search.FieldCache; import org.apache.lucene.search.FuzzyQuery; import org.apache.lucene.search.IndexSearcher; import org.apache.lucene.search.MatchAllDocsQuery; import org.apache.lucene.search.PhraseQuery; 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.TermQuery; import org.apache.lucene.search.TermRangeQuery; import org.apache.lucene.search.TimeLimitingCollector; import org.apache.lucene.search.TopDocs; import org.apache.lucene.search.TopScoreDocCollector; import org.apache.lucene.search.WildcardQuery; import org.apache.lucene.store.Directory; import org.apache.lucene.store.FSDirectory; import org.apache.lucene.store.LockObtainFailedException; import org.apache.lucene.store.RAMDirectory; import org.apache.lucene.util.Version; //修改分析器standardanalyzer为smartchineseAnalyzer public class Ramwriter implements Runnable { static RAMDirectory ram = null; static IndexWriter writer = null; static Document doc = null; static IndexWriter logwriter = null; static Directory dir = null; static IndexReader reader = null; static IndexSearcher searcher = null; static IndexSearcher sou_searcher = null; static int sum = 0; static Directory sou_dir = null; static TermQuery query = null; static Term term = null; static BufferedInputStream inBuff = null; static BufferedOutputStream outBuff = null; static boolean backbool; static File filelog = null; static FileWriter w = null; String path = this.getClass().getResource("/").getPath();// 路径 public boolean init() throws CorruptIndexException, LockObtainFailedException,// 初始化一次写入的writer IOException { boolean bool = true; ram = new RAMDirectory(); writer = new IndexWriter(ram, new SmartChineseAnalyzer(Version.LUCENE_30), true, IndexWriter.MaxFieldLength.UNLIMITED); return bool; } public void getfilewriter() throws IOException { filelog = new File(path + "indexdir/log.txt"); w = new FileWriter(filelog, true); } public void closefile() throws IOException { if (w == null) { } else { w.close(); } } public boolean ram_close(Directory directory) throws CorruptIndexException, IOException { boolean bool = true; directory.close(); return bool; } public boolean writer_close(IndexWriter indexwriter) throws CorruptIndexException, IOException { boolean bool = true; indexwriter.close(); return bool; } public synchronized boolean add_doc(String type, String theme, String sender, String information)// 同步写入doc throws CorruptIndexException, IOException { // 记录执行情况信息 /* * File filelog = new File(path+"indexdir/log.txt"); FileWriter w = new * FileWriter(filelog, true); */ if (w == null) { getfilewriter(); } else { // w.write("writer create ok"); } // w.write(path); boolean bool = true; try { if (ram == null) { init(); w.write(" not exits ram:\n" + "wrter restart" + (sum + 1) + "ok\n"); // System.out.println("wrter重新启动"+(sum + 1) + "ok"); } else { // w.write((sum + 1) + "ok"); } Field field = null; try { sum++; doc = new Document(); synchronized (this) { doc.add(new Field("id", String.valueOf(sum), Field.Store.YES, Field.Index.NOT_ANALYZED)); doc.add(new Field("type", type, Field.Store.YES, Field.Index.NOT_ANALYZED)); doc.add(new Field("sender", sender, Field.Store.YES, Field.Index.ANALYZED)); field = new Field("theme", theme, Field.Store.YES, Field.Index.ANALYZED); field.setBoost(1.2f); doc.add(field); doc.add(new Field("information", information, Field.Store.YES, Field.Index.ANALYZED)); doc.add(new Field("date", (new SimpleDateFormat( "y/MM/dd HH:mm:ss")).format(Calendar.getInstance() .getTime()), Field.Store.YES, Field.Index.NOT_ANALYZED)); writer.addDocument(doc); // 轮渡,写入硬盘 if ((sum % 100) == 0) { w.write((sum) + " document crate and write to hd\n"); logrotate(type); } } } catch (Exception e) { bool = false; w.write("write error:" + e.toString()+"\n"); } } catch (Exception e) { w.write("adddoc:" + e.toString() + "\n"); } finally { w.flush(); // w.close(); } if (sum > 10000000) { sum = 0; } return bool; } public synchronized boolean logrotate(String type) throws IOException {// 轮渡每100次,将RAM并入段操作,备份,并创建提示索引 // 记录执行信息 // File files = new File("indexdir/log.txt"); // String // path=this.getClass().getClassLoader().getResource("/").getPath();//路径 // File filelog = new File(path+"indexdir/log.txt"); // FileWriter w = new FileWriter(filelog, true); if (w == null) { getfilewriter(); } else { // w.write("writer create ok"); } boolean bool = true; boolean bool_file = false; try { // writer.optimize(); if (reader != null) { reader.close();// 关闭进实时读取的reader,关闭缓存 } else { } writer.close();// 合并之前关闭writer System.out.println("共计" + sum);// 累计文档数 File file = new File(path + "indexdir/" + type);// 动态创建索引文件夹 // File file_copy = new File(path+"indexdir/" + type+"copy");// // 动态创建备份索引文件夹 if (file.exists() == false) { file.mkdir(); // file_copy.mkdir(); System.out.println(file.getName() + ":" + file.getAbsolutePath()); bool_file = true; } else { System.out.println("已写入硬盘"); // file.delete(); bool_file = false; } // 合并索引 dir = FSDirectory.open(file); logwriter = new IndexWriter(dir, new SmartChineseAnalyzer( Version.LUCENE_30), bool_file, IndexWriter.MaxFieldLength.UNLIMITED); logwriter.addIndexesNoOptimize(ram); // 日志 w.write(sum + "document have write to hd \n"); // 优化方法不存在 logwriter.setMergeFactor(3);// 优化数据段,逻辑简单,合并为一个段 logwriter.optimize(5); logwriter.close(); //创建提示索引 // 具体备份操作 // 热备份。虽说没必要,优化为以后需求,每天晚上12点 // 条件 SimpleDateFormat simple = new SimpleDateFormat("Hmmss"); String backuptime = simple.format(Calendar.getInstance().getTime()); int inttime = Integer.parseInt(backuptime); if (inttime > 220000 && inttime <= 230000) { backbool = true; } else { backbool = false; } if (inttime > 230000 && inttime < 240000 && backbool) { w.write("have backup before\n"); backup(type); w.write("have backup after\n"); backbool = false; } else { w.write("time is not 24:0:0\n"); } // backup(type); ram.close(); dir.close(); //建立、更新索引提示 // if (inttime > 040000 && inttime < 050000 && backbool) { w.write("points:create points index before\n"); setspellindex(type); w.write("points:create points index ok\n"); //} //else{ w.write("points:time no create points index\n"); //} init(); } catch (Exception e) { w.write("logrotate:" + e.toString()+"\n"); System.out.println(e.toString()); } finally { // w.close(); w.flush(); } return bool; } // 先要删除原来的快照,在进行copy public void backup(String type) throws CorruptIndexException, LockObtainFailedException, IOException { if (w == null) { getfilewriter(); } else { // w.write("writer create ok"); } IndexDeletionPolicy policy = new KeepOnlyLastCommitDeletionPolicy(); SnapshotDeletionPolicy snapshotter = new SnapshotDeletionPolicy(policy); File file_copy = new File(path + "indexdir/" + type + "copy");// 动态创建备份索引文件夹 boolean back = false; if (file_copy.exists() == false) { file_copy.mkdir(); System.out.println(file_copy.getName() + ":" + file_copy.getAbsolutePath()); back = true; w.write("back:first backup\n"); } else { //完全删除一遍 delefiles(file_copy); file_copy.mkdir(); w.write("back:not first time backup\n"); // file.delete(); } logwriter = new IndexWriter(dir, new SmartChineseAnalyzer(Version.LUCENE_30) ,snapshotter, IndexWriter.MaxFieldLength.UNLIMITED); File Source_file = null; File dis_file = null; try { IndexCommit commit = snapshotter.snapshot(); Collection<String> fileNames = commit.getFileNames(); Iterator iter = fileNames.iterator(); String copypath=null; while (iter.hasNext()) { copypath=(String) iter.next(); Source_file = new File(path + "indexdir/" + type + "/" + copypath);// 获取源文件 dis_file = new File(path + "indexdir/" + type + "copy" + "/" + copypath);// 获取目的文件 copyFile(Source_file, dis_file); // logwriter.setMergeFactor(3); w.write("backup:is creating snapshot"+copypath+"\n"); } w.write("backup:snapshot ok\n"); } catch (Exception e) { if (w == null) { getfilewriter(); } else { // w.write("writer create ok"); w.write("backup:" + e.toString() + "\n"); } } finally { snapshotter.release(); logwriter.optimize(); logwriter.setMergeFactor(3); logwriter.close(); closefile(); getfilewriter(); } } public static boolean delefiles(File file){ boolean bools=true; try{ File files[]=file.listFiles(); for(File filesingle : files){ filesingle.delete(); } } catch(Exception e){ System.out.println(e.toString()); bools=false; } return bools; } // 复制文件 public static void copyFile(File sourceFile, File targetFile) throws IOException { try { // 新建文件输入流并对它进行缓冲 inBuff = new BufferedInputStream(new FileInputStream(sourceFile)); // 新建文件输出流并对它进行缓冲 outBuff = new BufferedOutputStream(new FileOutputStream(targetFile)); // 缓冲数组 byte[] b = new byte[1024 * 5]; int len; while ((len = inBuff.read(b)) != -1) { outBuff.write(b, 0, len); } // 刷新此缓冲的输出流 outBuff.flush(); } finally { // 关闭流 if (inBuff != null) inBuff.close(); if (outBuff != null) outBuff.close(); } } // /读取内容10次/2s记录,进实时读取ram,不关闭reader:漏洞:当writer重新打开,reader获取时出错,需要同步控制,filedcache,时间近实时快 public synchronized CopyOnWriteArrayList<String> get_theme_content( String type, String theme) throws IOException { // String // path=this.getClass().getClassLoader().getResource("/").getPath();//路径 CopyOnWriteArrayList<String> list = new CopyOnWriteArrayList<String>(); if (ram == null) { init(); // System.out.println("wrter重新启动"+(sum + 1) + "ok"); } else { } if (sum % 5 != 0) { list = null; } else { int i = 0; /* * File filelog = new File(path+"indexdir/log.txt"); FileWriter w = * new FileWriter(filelog, true); */ if (w == null) { getfilewriter(); } else { // w.write("writer create ok"); } // 对固定的 reader = writer.getReader(); /* * String[] id=FieldCache.DEFAULT.getStrings(reader, "id"); String[] * sender=FieldCache.DEFAULT.getStrings(reader, "sender"); String[] * information=FieldCache.DEFAULT.getStrings(reader, "information"); * String[] date=FieldCache.DEFAULT.getStrings(reader, "date"); long * a=System.currentTimeMillis(); for(i=0;i<id.length;i++){ * list.add(id[i]); list.add(sender[i]); list.add(information[i]); * list.add(date[i]); //System.out.println("::"+i); } long * b=System.currentTimeMillis()-a; System.out.println("时间:"b); */ searcher = new IndexSearcher(reader); MapFieldSelector s = new MapFieldSelector("sender"); MatchAllDocsQuery all_query = new MatchAllDocsQuery(); TopDocs tops = searcher.search(all_query, null, 20, new Sort( new SortField("date", SortField.STRING, true))); // long a=System.currentTimeMillis(); for (ScoreDoc score : tops.scoreDocs) { i++; doc = searcher.doc(score.doc); // list.add(doc.get("id")); list.add(doc.get("information") + ":" + doc.get("date") + "\n" + " " + doc.get("sender")); // System.out.println("已有查出" + i); } // long b=System.currentTimeMillis(); // System.out.println("时间:"+a+"::"+b); w.write("content:write out " + i + "ok!\n"); // w.close(); w.flush(); } return list; } // 仅针对近视实的关闭,可不使用 public boolean get_theme_content_close() throws IOException { boolean bool = true; searcher.close(); reader.close(); return bool; } // 查询更早的对单个商品的记录 public synchronized CopyOnWriteArrayList<String> get_theme_history( String type, String theme) throws IOException { // String // path=this.getClass().getClassLoader().getResource("/").getPath();//路径 int i = 0; CopyOnWriteArrayList<String> list = new CopyOnWriteArrayList<String>(); // File filelog = new File(path+"indexdir/log.txt"); // FileWriter w = new FileWriter(filelog, true); if (w == null) { getfilewriter(); } else { // w.write("writer create ok"); } // 对固定的 // 本质上writer.getReader(); File file = new File(path + "indexdir/" + type); if (file.exists()) {// 存在 if (theme == null || theme.equals("")) { theme = "*:*"; } else { } sou_dir = FSDirectory.open(file); // FieldSelector chose=new MapFieldSelector("id",""); sou_searcher = new IndexSearcher(sou_dir); term = new Term("theme", theme); query = new TermQuery(term); TopDocs tops = sou_searcher.search(query, 1000); for (ScoreDoc score : tops.scoreDocs) { i++; doc = sou_searcher.doc(score.doc); // doc.get("id") list.add(String.valueOf(i) + ":" + doc.get("sender") + ":" + doc.get("date") + ":" + doc.get("information")); // list.add(); // list.add(); // list.add(); // System.out.println("history:"+doc.get("id")); } w.write("history:write out " + i + "ok!"+"\n"); // w.close(); w.flush(); } else { w.write("no content\n"); } return list; } // 空值问题, // 根据内容查询,type,theme,高亮显示,禁止查询时间3s(不可取),搜索内容进行分析bunweik public synchronized CopyOnWriteArrayList<String> searcher_interest( String type, String theme, String sender, String information) throws IOException, ParseException, java.text.ParseException, InvalidTokenOffsetsException { // String // path=this.getClass().getClassLoader().getResource("/").getPath();//路径 CopyOnWriteArrayList<String> list = new CopyOnWriteArrayList<String>(); int i = 0; if (information == null || information.equals("")) { information = "*:*"; } else { } // File filelog = new File(path+"indexdir/log.txt"); // FileWriter w = new FileWriter(filelog, true); if (w == null) { getfilewriter(); } else { // w.write("writer create ok"); } // 对固定的 // 本质上writer.getReader(); File file = new File(path + "indexdir/" + type); sou_dir = FSDirectory.open(file); sou_searcher = new IndexSearcher(sou_dir); QueryParser parser = new QueryParser(Version.LUCENE_30, "information", new SmartChineseAnalyzer(Version.LUCENE_30)); Query query_infor = parser.parse(information);// 解析信息 // QueryParser parser_time=new QueryParser(Version.LUCENE_30,"date",new // SmartChineseAnalyzer(Version.LUCENE_30)); parser.parse(information);// 解析信息 TermQuery theme_query = new TermQuery(new Term("theme", theme));// 商品名查询 FuzzyQuery sender_query = new FuzzyQuery(new Term("sender", sender));// 发送 WildcardQuery wildquery = new WildcardQuery(new Term("sender", "?" + sender + "*")); BooleanQuery sender_qeruy = new BooleanQuery(); sender_qeruy.add(sender_query, Occur.SHOULD); sender_qeruy.add(wildquery, Occur.SHOULD); // 时间解析范围 SimpleDateFormat simple = new SimpleDateFormat("y/MM/dd"); // Date time=simple.parse(date); // Date date_from=new Date(time.getTime() - 5 * 24 * 60 * 60 * // 1000);//五天 // String from_time=simple.format(date_from); // Query // parser_date=parser_time.parse("date:["+from_time+" TO "+date+"]"); BooleanQuery bool_query = new BooleanQuery(); bool_query.add(theme_query, Occur.MUST); // bool_query.add(parser_date,Occur.MUST); bool_query.add(query_infor, Occur.SHOULD); bool_query.add(sender_qeruy, Occur.SHOULD); TokenStream stream = null; // 时间限制,在js里面控制更好 // TopScoreDocCollector tops_col=TopScoreDocCollector.create(500,false); // Collector col=new TimeLimitingCollector(tops_col,3000); TopDocs tops = sou_searcher.search(bool_query, null, 500, new Sort( new SortField("date", SortField.STRING, true))); String text = null; TermQuery infor_query = new TermQuery(new Term("infor", information)); for (ScoreDoc score : tops.scoreDocs) { i++; doc = sou_searcher.doc(score.doc); // list.add(doc.get("id")); // 高亮显示 text = doc.get("information"); stream = (new SimpleAnalyzer()).tokenStream("infor", new StringReader(text)); QueryScorer queryscore = new QueryScorer(infor_query, "infor"); Highlighter lighter = new Highlighter(queryscore); SimpleSpanFragmenter fragmenter = new SimpleSpanFragmenter( queryscore); lighter.setTextFragmenter(fragmenter); // list.add(); list.add(String.valueOf(i) + ":" + doc.get("sender") + ":" + doc.get("date") + ":" + lighter.getBestFragment(stream, text)); // list.add(); // System.out.println(lighter.getBestFragment(stream, text)); // System.out.println("搜索结果"+doc.get("id")); } w.write("interest:write out " + i + "ok!\n"); // w.close(); w.flush(); return list; } public synchronized String setspellindex(String type) throws IOException{ File file=new File(path+"points/"+type); Directory dir=FSDirectory.open(file);//目的索引 SpellChecker spell=new SpellChecker(dir); Directory dir2=FSDirectory.open(new File(path+"indexdir/"+type));//源索引 IndexReader reader=IndexReader.open(dir2); LuceneDictionary lucene=new LuceneDictionary(reader,"theme"); /* Iterator<String> iter=lucene.getWordsIterator(); while(iter.hasNext()){ System.out.println(":"+iter.next()); }*/ spell.indexDictionary(lucene); dir.close(); dir2.close(); return path; } /*public static void main(String args[]) throws CorruptIndexException, IOException, ParseException, java.text.ParseException, InvalidTokenOffsetsException {// 测试数据 Ramwriter r = new Ramwriter(); for (int i = 1; i <= 30; i++) { r.add_doc("Digital", "酱油"+i, "sharesss" + i, "sharefssssly" + i); r.add_doc("Digital", "麻辣烫", "sharesss" , "sharefssssly" ); r.add_doc("Digital", "麻辣酱", "sharesss" , "sharefssssly" ); r.add_doc("Digital", "麻辣火锅", "sharesss" , "sharefssssly" ); } CopyOnWriteArrayList<String> list = new CopyOnWriteArrayList<String>(); list = r.searcher_interest("Digital", "share", "sharesss" , "sharefssssly" ); Iterator iter = list.iterator(); while (iter.hasNext()) { System.out.println(iter.next()); } // System.out.println(r.sum); // r.get_theme_history("Digital", "share"); r.searcher_interest("Digital", "share", "","" ); // //r.logrotate("Digital"); // r.backup("Digital"); }*/ public void run() { // TODO Auto-generated method stub } }
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学习Lucene 4.4和Elasticsearch的源码,可以帮助开发者深入理解信息检索的核心原理,包括倒排索引、TF-IDF算法、布尔模型等。同时,也能掌握如何在实际项目中设计和优化搜索系统,提高数据检索效率。 对于Elastic...
结合笔者的实际开发经验,总结了一些新的开发技巧和开发思路,并对网上流传的一些错误...本书既可为零起点的Lucene初学者提供系统全面的学习指导,也可帮助有相关经验的开发者解决在开发过程中遇到的一些难题和疑惑。
Lucene采用模块化的设计思路,主要包括以下几个核心模块: - **索引模块**:负责索引的创建和维护。 - **搜索模块**:提供搜索接口,实现搜索功能。 - **分析模块**:提供文本分析工具,包括分词、词干化等功能。 -...
Lucene是一个开源的全文检索引擎工具包,它为文本数据提供了索引和搜索功能。...一个开发人员通过学习Lucene,不仅可以获得构建全文检索系统的能力,还能够理解到许多与信息检索相关的技术细节和优化思路。
尽管Lucene-JDBC已经不再被积极维护,但它所体现的设计思路和方法论依然值得学习。现代的替代方案,如Elasticsearch,同样支持将索引数据存储在分布式数据库中,且提供了更丰富的功能和更高的性能。然而,理解Lucene...
其中,正向最大匹配法是一种常用的分词方法,其基本思路是从左向右取待分词串的最大长度作为匹配长度,然后查找词典,若存在,则匹配成功;否则减少一个字长后继续查找,直到找到为止。 #### 三、基于Lucene的中文...
8. 学习资料:这个项目作为一个学习资料,适合对Web开发和搜索引擎感兴趣的初学者或进阶者,他们可以通过阅读源代码和论文,学习如何在实际项目中应用ASP.NET、Ajax和Lucene。 9. 其他标签:数据集可能包含用于测试...
开发者可以通过阅读和分析这些代码,学习如何在ASP.NET环境中集成Ajax和Lucene,以及如何处理搜索逻辑、用户交互和数据检索。 7. **论文**:通常,毕业设计会包含一篇详细的技术论文,解释设计思路、实施过程、遇到...
描述中的“javaso开发文档说明”表明,该压缩包中可能包含了详细的开发文档,这将有助于理解项目的架构、设计思路以及如何运行和测试系统。开发文档通常会涵盖以下几个部分: 1. **项目概述**:介绍项目的背景、...
ASP.NET是一种广泛使用的Web开发框架,由微软公司提供,它为开发者提供了构建动态网站、Web应用程序和服务的强大工具。...对于学习Web开发,尤其是对搜索引擎技术感兴趣的开发者来说,这是一个宝贵的学习资源。
9. **论文**:标签中的“论文”可能指的是该项目相关的技术文档或研究报告,解释了系统的设计思路、实现方法和性能评估,这对于学术研究或项目改进具有参考价值。 10. **系统集成**:此公交搜索系统可能还涉及与...