Lucene实战之基于StandardAnalyzer读写索引

前言

      使用lucene创建索引时如果指定了解析器，则需要读写都使用这个解析器，目前我发现也就是在处理中文这块比较麻烦，像你在使用solr时如果配置了ik分词，则需要把index清空重新创建才能继续搜索。

      本篇引用lucene-6.4.0和4.x的几个关键类会有不同的地方。

创建索引

 public void index(){

        Directory dir=null;
        Analyzer analyzer=null;
        IndexWriterConfig config=null;
        IndexWriter indexWriter=null;
        try{
            /**
             * SimpleFSDirectory 不能很好支持多线程操作
             * **/
            dir =new SimpleFSDirectory(Paths.get(INDEX_URL));

            analyzer=new StandardAnalyzer();
            config =new IndexWriterConfig(analyzer);
            /**
             * IndexWriter(Directory d,IndexWriterConfig config)
             * **/
            indexWriter =new IndexWriter(dir,config);

            indexWriter.deleteAll();
            List<UploadBook> books =bookDao.listAllBooks();
            Document document=null;

            SimpleDateFormat formatter = new SimpleDateFormat("yyyy-MM-dd HH:mm:ss");

            for(UploadBook book:books){
                document=new Document();
                document.add(new Field("id",book.getId().toString(), TextField.TYPE_STORED));
                document.add(new Field("ip",book.getIp(), TextField.TYPE_STORED));
                document.add(new Field("title",book.getOriginFileName(), TextField.TYPE_STORED));

                document.add(new Field("content", PdfReader.read(INDEX_PDF+book.getNewFileName()),TextField.TYPE_STORED));
                document.add(new Field("createtime",formatter.format(book.getCreateTime()), TextField.TYPE_STORED));

                indexWriter.addDocument(document);
            }

            indexWriter.commit();

            System.out.println("======索引创建完成，公创建"+books.size()+"条索引========");
        }catch (IOException ex){
            ex.printStackTrace();
        }
        catch(Exception ex){
            ex.printStackTrace();
        }finally {
            if(indexWriter !=null){
                try{
                    indexWriter.close();
                }catch (IOException ex){
                    System.out.println("======indexWriter close exception========");
                }
            }
        }

    }

读取索引

 public static List<Book> search2(String kw){
        Directory dir=null;
        Analyzer analyzer=null;
        List<Book> list = new ArrayList<Book>();
        try{
            dir= FSDirectory.open(Paths.get("e:\soso\index"));
            analyzer=new StandardAnalyzer();

            DirectoryReader reader =DirectoryReader.open(dir);
            IndexSearcher searcher=new IndexSearcher(reader);

            QueryParser parser=new QueryParser("content",analyzer);
            Query query =parser.parse(kw);

            ScoreDoc[] docs=searcher.search(query,100).scoreDocs;

            for (int i = 0; i < docs.length; i++) {
                Document firstHit = searcher.doc(docs[i].doc);

                Book book=new Book();
                book.setId(Integer.parseInt(firstHit.getField("id").stringValue()));
                book.setIp(firstHit.getField("ip").stringValue());

                String title=firstHit.getField("title").stringValue();
                title=title.substring(0,title.lastIndexOf("."));
                book.setTitle(title);

                String content=firstHit.getField("content").stringValue();
                if(content.length()>=500){
                    content=content.substring(0,500)+"......";
                }
                book.setContent(content);

                SimpleDateFormat format=new SimpleDateFormat("yyyy-MM-mm");
                Date date =format.parse(firstHit.getField("createtime").stringValue());
                book.setCreateTime(format.format(date));

                list.add(book);

            }

        }catch(Exception ex){

        }finally {
            try{
                dir.close();

            }catch(IOException ex){
                ex.printStackTrace();
            }
        }

        return list;
    }