前言
搞检索的，应该多少都会了解Lucene一些，它开源而且简单上手，官方API足够编写些小DEMO。并且根据倒排索引，实现快速检索。本文就简单的实现增量添加索引，删除索引，通过关键字查询，以及更新索引等操作。
目前博猪使用的不爽的地方就是，读取文件内容进行全文检索时，需要自己编写读取过程（这个solr免费帮我们实现）。而且创建索引的过程比较慢，还有很大的优化空间，这个就要细心下来研究了。
创建索引
Lucene在进行创建索引时，根据前面一篇博客，已经讲完了大体的流程，这里再简单说下：
1 Directory directory = FSDirectory.open("/tmp/testindex");
2 IndexWriterConfig config = new IndexWriterConfig(Version.LUCENE_CURRENT, analyzer);
3 IndexWriter iwriter = new IndexWriter(directory, config);
4 Document doc = new Document();
5 String text = "This is the text to be indexed.";
6 doc.add(new Field("fieldname", text, TextField.TYPE_STORED)); iwriter.close();
1 创建Directory，获取索引目录
2 创建词法分析器，创建IndexWriter对象
3 创建document对象，存储数据
4 关闭IndexWriter，提交
1 /**
2 * 建立索引
3 *
4 * @param args
5 */
6 public static void index() throws Exception {
7
8 String text1 = "hello,man!";
9 String text2 = "goodbye,man!";
10 String text3 = "hello,woman!";
11 String text4 = "goodbye,woman!";
12
13 Date date1 = new Date();
14 analyzer = new StandardAnalyzer(Version.LUCENE_CURRENT);
15 directory = FSDirectory.open(new File(INDEX_DIR));
16
17 IndexWriterConfig config = new IndexWriterConfig(
18 Version.LUCENE_CURRENT, analyzer);
19 indexWriter = new IndexWriter(directory, config);
20
21 Document doc1 = new Document();
22 doc1.add(new TextField("filename", "text1", Store.YES));
23 doc1.add(new TextField("content", text1, Store.YES));
24 indexWriter.addDocument(doc1);
25
26 Document doc2 = new Document();
27 doc2.add(new TextField("filename", "text2", Store.YES));
28 doc2.add(new TextField("content", text2, Store.YES));
29 indexWriter.addDocument(doc2);
30
31 Document doc3 = new Document();
32 doc3.add(new TextField("filename", "text3", Store.YES));
33 doc3.add(new TextField("content", text3, Store.YES));
34 indexWriter.addDocument(doc3);
35
36 Document doc4 = new Document();
37 doc4.add(new TextField("filename", "text4", Store.YES));
38 doc4.add(new TextField("content", text4, Store.YES));
39 indexWriter.addDocument(doc4);
40
41 indexWriter.commit();
42 indexWriter.close();
43
44 Date date2 = new Date();
45 System.out.println("创建索引耗时：" + (date2.getTime() - date1.getTime()) + "ms\n");
46 }
增量添加索引
Lucene拥有增量添加索引的功能，在不会影响之前的索引情况下，添加索引，它会在何时的时机，自动合并索引文件。
1 /**
2 * 增加索引
3 *
4 * @throws Exception
5 */
6 public static void insert() throws Exception {
7 String text5 = "hello,goodbye,man,woman";
8 Date date1 = new Date();
9 analyzer = new StandardAnalyzer(Version.LUCENE_CURRENT);
10 directory = FSDirectory.open(new File(INDEX_DIR));
11
12 IndexWriterConfig config = new IndexWriterConfig(
13 Version.LUCENE_CURRENT, analyzer);
14 indexWriter = new IndexWriter(directory, config);
15
16 Document doc1 = new Document();
17 doc1.add(new TextField("filename", "text5", Store.YES));
18 doc1.add(new TextField("content", text5, Store.YES));
19 indexWriter.addDocument(doc1);
20
21 indexWriter.commit();
22 indexWriter.close();
23
24 Date date2 = new Date();
25 System.out.println("增加索引耗时：" + (date2.getTime() - date1.getTime()) + "ms\n");
26 }
删除索引
Lucene也是通过IndexWriter调用它的delete方法，来删除索引。我们可以通过关键字，删除与这个关键字有关的所有内容。如果仅仅是想要删除一个文档，那么最好就顶一个唯一的ID域，通过这个ID域，来进行删除操作。
1 /**
2 * 删除索引
3 *
4 * @param str 删除的关键字
5 * @throws Exception
6 */
7 public static void delete(String str) throws Exception {
8 Date date1 = new Date();
9 analyzer = new StandardAnalyzer(Version.LUCENE_CURRENT);
10 directory = FSDirectory.open(new File(INDEX_DIR));
11
12 IndexWriterConfig config = new IndexWriterConfig(
13 Version.LUCENE_CURRENT, analyzer);
14 indexWriter = new IndexWriter(directory, config);
15
16 indexWriter.deleteDocuments(new Term("filename",str));
17
18 indexWriter.close();
19
20 Date date2 = new Date();
21 System.out.println("删除索引耗时：" + (date2.getTime() - date1.getTime()) + "ms\n");
22 }
更新索引
Lucene没有真正的更新操作，通过某个fieldname，可以更新这个域对应的索引，但是实质上，它是先删除索引，再重新建立的。
1 /**
2 * 更新索引
3 *
4 * @throws Exception
5 */
6 public static void update() throws Exception {
7 String text1 = "update,hello,man!";
8 Date date1 = new Date();
9 analyzer = new StandardAnalyzer(Version.LUCENE_CURRENT);
10 directory = FSDirectory.open(new File(INDEX_DIR));
11
12 IndexWriterConfig config = new IndexWriterConfig(
13 Version.LUCENE_CURRENT, analyzer);
14 indexWriter = new IndexWriter(directory, config);
15
16 Document doc1 = new Document();
17 doc1.add(new TextField("filename", "text1", Store.YES));
18 doc1.add(new TextField("content", text1, Store.YES));
19
20 indexWriter.updateDocument(new Term("filename","text1"), doc1);
21
22 indexWriter.close();
23
24 Date date2 = new Date();
25 System.out.println("更新索引耗时：" + (date2.getTime() - date1.getTime()) + "ms\n");
26 }
通过索引查询关键字
Lucene的查询方式有很多种，这里就不做详细介绍了。它会返回一个ScoreDoc的集合，类似ResultSet的集合，我们可以通过域名获取想要获取的内容。
1 /**
2 * 关键字查询
3 *
4 * @param str
5 * @throws Exception
6 */
7 public static void search(String str) throws Exception {
8 directory = FSDirectory.open(new File(INDEX_DIR));
9 analyzer = new StandardAnalyzer(Version.LUCENE_CURRENT);
10 DirectoryReader ireader = DirectoryReader.open(directory);
11 IndexSearcher isearcher = new IndexSearcher(ireader);
12
13 QueryParser parser = new QueryParser(Version.LUCENE_CURRENT, "content",analyzer);
14 Query query = parser.parse(str);
15
16 ScoreDoc[] hits = isearcher.search(query, null, 1000).scoreDocs;
17 for (int i = 0; i < hits.length; i++) {
18 Document hitDoc = isearcher.doc(hits[i].doc);
19 System.out.println(hitDoc.get("filename"));
20 System.out.println(hitDoc.get("content"));
21 }
22 ireader.close();
23 directory.close();
24 }
全部代码
1 package test;View Code
2
3 import java.io.File;
4 import java.util.Date;
5 import java.util.List;
6
7 import org.apache.lucene.analysis.Analyzer;
8 import org.apache.lucene.analysis.standard.StandardAnalyzer;
9 import org.apache.lucene.document.Document;
10 import org.apache.lucene.document.LongField;
11 import org.apache.lucene.document.TextField;
12 import org.apache.lucene.document.Field.Store;
13 import org.apache.lucene.index.DirectoryReader;
14 import org.apache.lucene.index.IndexWriter;
15 import org.apache.lucene.index.IndexWriterConfig;
16 import org.apache.lucene.index.Term;
17 import org.apache.lucene.queryparser.classic.QueryParser;
18 import org.apache.lucene.search.IndexSearcher;
19 import org.apache.lucene.search.Query;
20 import org.apache.lucene.search.ScoreDoc;
21 import org.apache.lucene.store.Directory;
22 import org.apache.lucene.store.FSDirectory;
23 import org.apache.lucene.util.Version;
24
25 public class TestLucene {
26 // 保存路径
27 private static String INDEX_DIR = "D:\\luceneIndex";
28 private static Analyzer analyzer = null;
29 private static Directory directory = null;
30 private static IndexWriter indexWriter = null;
31
32 public static void main(String[] args) {
33 try {
34 // index();
35 search("man");
36 // insert();
37 // delete("text5");
38 // update();
39 } catch (Exception e) {
40 e.printStackTrace();
41 }
42 }
43 /**
44 * 更新索引
45 *
46 * @throws Exception
47 */
48 public static void update() throws Exception {
49 String text1 = "update,hello,man!";
50 Date date1 = new Date();
51 analyzer = new StandardAnalyzer(Version.LUCENE_CURRENT);
52 directory = FSDirectory.open(new File(INDEX_DIR));
53
54 IndexWriterConfig config = new IndexWriterConfig(
55 Version.LUCENE_CURRENT, analyzer);
56 indexWriter = new IndexWriter(directory, config);
57
58 Document doc1 = new Document();
59 doc1.add(new TextField("filename", "text1", Store.YES));
60 doc1.add(new TextField("content", text1, Store.YES));
61
62 indexWriter.updateDocument(new Term("filename","text1"), doc1);
63
64 indexWriter.close();
65
66 Date date2 = new Date();
67 System.out.println("更新索引耗时：" + (date2.getTime() - date1.getTime()) + "ms\n");
68 }
69 /**
70 * 删除索引
71 *
72 * @param str 删除的关键字
73 * @throws Exception
74 */
75 public static void delete(String str) throws Exception {
76 Date date1 = new Date();
77 analyzer = new StandardAnalyzer(Version.LUCENE_CURRENT);
78 directory = FSDirectory.open(new File(INDEX_DIR));
79
80 IndexWriterConfig config = new IndexWriterConfig(
81 Version.LUCENE_CURRENT, analyzer);
82 indexWriter = new IndexWriter(directory, config);
83
84 indexWriter.deleteDocuments(new Term("filename",str));
85
86 indexWriter.close();
87
88 Date date2 = new Date();
89 System.out.println("删除索引耗时：" + (date2.getTime() - date1.getTime()) + "ms\n");
90 }
91 /**
92 * 增加索引
93 *
94 * @throws Exception
95 */
96 public static void insert() throws Exception {
97 String text5 = "hello,goodbye,man,woman";
98 Date date1 = new Date();
99 analyzer = new StandardAnalyzer(Version.LUCENE_CURRENT);
100 directory = FSDirectory.open(new File(INDEX_DIR));
101
102 IndexWriterConfig config = new IndexWriterConfig(
103 Version.LUCENE_CURRENT, analyzer);
104 indexWriter = new IndexWriter(directory, config);
105
106 Document doc1 = new Document();
107 doc1.add(new TextField("filename", "text5", Store.YES));
108 doc1.add(new TextField("content", text5, Store.YES));
109 indexWriter.addDocument(doc1);
110
111 indexWriter.commit();
112 indexWriter.close();
113
114 Date date2 = new Date();
115 System.out.println("增加索引耗时：" + (date2.getTime() - date1.getTime()) + "ms\n");
116 }
117 /**
118 * 建立索引
119 *
120 * @param args
121 */
122 public static void index() throws Exception {
123
124 String text1 = "hello,man!";
125 String text2 = "goodbye,man!";
126 String text3 = "hello,woman!";
127 String text4 = "goodbye,woman!";
128
129 Date date1 = new Date();
130 analyzer = new StandardAnalyzer(Version.LUCENE_CURRENT);
131 directory = FSDirectory.open(new File(INDEX_DIR));
132
133 IndexWriterConfig config = new IndexWriterConfig(
134 Version.LUCENE_CURRENT, analyzer);
135 indexWriter = new IndexWriter(directory, config);
136
137 Document doc1 = new Document();
138 doc1.add(new TextField("filename", "text1", Store.YES));
139 doc1.add(new TextField("content", text1, Store.YES));
140 indexWriter.addDocument(doc1);
141
142 Document doc2 = new Document();
143 doc2.add(new TextField("filename", "text2", Store.YES));
144 doc2.add(new TextField("content", text2, Store.YES));
145 indexWriter.addDocument(doc2);
146
147 Document doc3 = new Document();
148 doc3.add(new TextField("filename", "text3", Store.YES));
149 doc3.add(new TextField("content", text3, Store.YES));
150 indexWriter.addDocument(doc3);
151
152 Document doc4 = new Document();
153 doc4.add(new TextField("filename", "text4", Store.YES));
154 doc4.add(new TextField("content", text4, Store.YES));
155 indexWriter.addDocument(doc4);
156
157 indexWriter.commit();
158 indexWriter.close();
159
160 Date date2 = new Date();
161 System.out.println("创建索引耗时：" + (date2.getTime() - date1.getTime()) + "ms\n");
162 }
163
164 /**
165 * 关键字查询
166 *
167 * @param str
168 * @throws Exception
169 */
170 public static void search(String str) throws Exception {
171 directory = FSDirectory.open(new File(INDEX_DIR));
172 analyzer = new StandardAnalyzer(Version.LUCENE_CURRENT);
173 DirectoryReader ireader = DirectoryReader.open(directory);
174 IndexSearcher isearcher = new IndexSearcher(ireader);
175
176 QueryParser parser = new QueryParser(Version.LUCENE_CURRENT, "content",analyzer);
177 Query query = parser.parse(str);
178
179 ScoreDoc[] hits = isearcher.search(query, null, 1000).scoreDocs;
180 for (int i = 0; i < hits.length; i++) {
181 Document hitDoc = isearcher.doc(hits[i].doc);
182 System.out.println(hitDoc.get("filename"));
183 System.out.println(hitDoc.get("content"));
184 }
185 ireader.close();
186 directory.close();
187 }
188 }
参考资料
http://www.cnblogs.com/xing901022/p/3933675.html