权值

【概述】

在数学领域，权值指加权平均数中的每个数的频数，也称为权数或权重。在搜索引擎中，权值越高的内容在排序中越靠前。

实际应用中可以通过修改权值来重新调整索引在列表中的排序位置。

【示例】

 1     /**
 2      * 创建索引
 3      */
 4     @Test
 5     public void testIndex(){
 6         //存储3篇文章的信息。包括：id、标题、作者、内容
 7         int[] ids = {1,2,3};
 8         String[] titles = {"Hello","I love you","morning"};
 9         String[] authors = {"Hello Mike","HanMeimei","Tom"};
10         String[] contents= {"Hello,My Name Is Mike; good","Tome,I Love You; good，good,good","Good Moring,I'm so sorry; good,，good,good，good,good"};
11         
12         IndexWriter writer = null;
13         
14         try {
15             //1、创建Directory
16             Directory directory = FSDirectory.open(new File("E:\\lucene\\index2"));
17             
18             //2、创建Writer
19             ......
20             
21             for(int i = 0;i<ids.length;i++){
22                 doc = new Document();
23                 
24                 //为文档添加域(属性)
25                 String id = Integer.toString(ids[i]);
26                 doc.add(new Field("id",id,Field.Store.YES,Field.Index.NOT_ANALYZED_NO_NORMS));
27                 doc.add(new Field("title",titles[i],Field.Store.YES,Field.Index.NOT_ANALYZED));
28                 doc.add(new Field("author",authors[i],Field.Store.YES,Field.Index.NOT_ANALYZED));
29                 doc.add(new Field("content", contents[i],Field.Store.NO,Field.Index.ANALYZED));
30                 
31                 //修改索引的权值
32                 //默认权值为1.0
33                 //将Id为1的数据权值调整到5.0
34                 if(ids[i] == 1)
35                     doc.setBoost(5.0f);
36                 
37                 writer.addDocument(doc);
38             }
39         } catch (IOException e) {
40             e.printStackTrace();
41         }
42         finally{
43             if(writer != null)
44                 try {
45                     writer.close();
46                 } catch (CorruptIndexException e) {
47                     // TODO Auto-generated catch block
48                     e.printStackTrace();
49                 } catch (IOException e) {
50                     // TODO Auto-generated catch block
51                     e.printStackTrace();
52                 }
53         }
54     }