Lucene09-lucene highlighting

Directory

• 1 What is highlighting
• 2 Highlighting implementation
  • 2.1 Configuring the Pom.xml file, adding highlight support
  • 2.2 Code implementation
  • 2.3 Customizing HTML tags highlighting

1 What is highlighting

Highlighting is a feature of full-text indexing, which refers to highlighting keywords in search results (bold and add color).

2 Highlighting implementation

Lucene provides a highlight component that supports highlighting.

2.1 Configuring the Pom.xml file, adding highlight support

<project>    <properties>        <project.build.sourceEncoding>UTF-8</project.build.sourceEncoding>        <!-- mysql版本 -->        <mysql.version>5.1.30</mysql.version>        <!-- lucene版本 -->        <lucene.version>4.10.3</lucene.version>        <!-- ik分词器版本 -->        <ik.version>2012_u6</ik.version>    </properties>        <dependencies>        // ......        <!--lucene高亮显示 -->        <dependency>            <groupId>org.apache.lucene</groupId>            <artifactId>lucene-highlighter</artifactId>            <version>${lucene.version}</version>        </dependency>    </dependencies></project>

2.2 Code implementation

1. creates a score object (Queryscorer) that calculates the scoring for the highlighted content;
The
2. creates an output fragment object (Fragmenter) that slices the highlighted content;
3. Create a highlighted Component Object (highlighter) for highlighting;
4. Create parser Object (Analyzer) for Word segmentation;
5. Use the Tokensources class to get the Stream object (Tokenstream) of the highlighted content;
6. use the Highlighter object to finish highlighting.

/** * Encapsulates the search method (highlighted method) */private void Searcherhighlighter (query query) throws Exception {//print the Queries object generated by the querying syntax System.     OUT.PRINTLN ("Query syntax:" + query); 1. Create an index library directory location Object (directory) that specifies the location of the index Library Directory directory = Fsdirectory.open ("/users/healchow/documents/       Index "));       2. Create an index read object (indexreader) to read the index data into memory indexreader reader = directoryreader.open (directory);       3. Create index Search object (indexsearcher) to perform search Indexsearcher searcher = new Indexsearcher (reader); 4.  Perform a search using the Indexsearcher object, return the search result set topdocs//parameter one: Use the query object, parameter two: Specify the first n topdocs topdocs = searcher.search (query,) after sorting the search results to be returned       10); Add highlight processing ============================== start//1. Create a Score object (Queryscorer) to rate the highlighted content queryscorer qs = new Querysco     RER (query);       2. Create an output fragment object (Fragmenter) to slice the highlighted content fragmenter Fragmenter = new Simplespanfragmenter (QS);    3. Create a Highlight Component Object (highlighter) to enable highlighting highlighter lighter = new highlighter (QS); Set the Slice object Lighter.settextfragmenter (fragmEnter);       4. Establish the Analyzer object (Analyzer) for the word Analyzer Analyzer = new Ikanalyzer (); Added highlight processing ============================== end//5.       Processing result set//5.1 print the number of results actually queried System.out.println ("Number of results actually queried:" + topdocs.totalhits);      5.2 Gets the result array of the search//Scoredoc The ID of the document and its score scoredoc[] Scoredocs = Topdocs.scoredocs;        for (Scoredoc Scoredoc:scoredocs) {System.out.println ("= = = = = = = = = = = = = = = = = = = = =");        Gets the ID and rating of the document int docId = Scoredoc.doc;        FLOAT score = Scoredoc.score;           System.out.println ("Document Id=" + DocId + ", score =" + score);          Querying document data based on document ID-equivalent to querying data in a relational database based on primary key ID doc = Searcher.doc (docId);        System.out.println ("Book ID:" + doc.get ("bookId"));        Implementation of the name of the book highlighting String bookname = Doc.get ("BookName"); if (bookname! = null) {//5. Use the Tokensources class to get the highlighted content stream object (tokenstream)//Gettokenstream method: Gets the current document's flow pair Image//Parameter one: Current Document Object//Parameter two: the domain name to be highlighted           Parameter three: Parser object Tokenstream tokenstream = Tokensources.gettokenstream (Doc, "BookName", analyzer);            6. Use the highlight Component object to finish highlighting//Getbestfragment method: Get the highlighted result content//parameter one: Current Document object's stream object        Parameter two: target content to be highlighted bookname = Lighter.getbestfragment (Tokenstream, bookname);        } System.out.println ("Book Name:" + bookname);        System.out.println ("Book Price:" + doc.get ("Bookprice"));        System.out.println ("Book Picture:" + doc.get ("Bookpic"));    System.out.println ("Book Description:" + doc.get ("Bookdesc")); }//8. Close resource Reader.close ();}

/** * 测试高亮显示 需求：把搜索结果中，图书名称进行高亮显示(关键词值java) * @throws Exception  */@Testpublic void testHighlighter() throws Exception {    //1.创建查询对象    TermQuery tq = new TermQuery(new Term("bookName","java"));       // 2.执行高亮搜索    this.searcherHighlighter(tq);}

2.3 Customizing HTML tags highlighting

• Question: In the actual project, how to implement the custom HTML tags, the search results highlighted?
  1. Create HTML tag formatting objects (Simplehtmlformatter);
  2. Creates a highlight Component Object (highlighter), specifying the use of the Simplehtmlformatter object.

// 增加高亮显示处理 ============================== start// 1.建立分值对象(QueryScorer), 用于对高亮显示内容打分QueryScorer qs = new QueryScorer(query);// 2.建立输出片段对象(Fragmenter), 用于把高亮显示内容切片Fragmenter fragmenter = new SimpleSpanFragmenter(qs);// 3.建立高亮组件对象(Highlighter), 实现高亮显示// 3.1.实现自定义的HTML标签进行高亮显示搜索结果// 1) 建立高亮显示HTML格式化标签对象(SimpleHTMLFormatter), 参数说明: // preTag: 指定HTML标签的开始部分(<font color='red'>)// postTag: 指定HTML标签的结束部分(</font>)SimpleHTMLFormatter formatter = new SimpleHTMLFormatter("<font color='red'>", "</font>");// 2) 指定高亮显示组件对象（Highter）, 使用SimpleHTMLFormatter对象Highlighter lighter = new Highlighter(formatter, qs);// 设置切片对象lighter.setTextFragmenter(fragmenter);// 4.建立分析器对象(Analyzer), 用于分词Analyzer analyzer = new IKAnalyzer();// 增加高亮显示处理 ============================== end

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Author: Ma_shoufeng (Ma Ching)

Source: Blog Park Ma Ching's Blog

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Lucene09-lucene highlighting