Java Lucene-6.4.2:未找到DefaultSimilarity类，尝试添加查询。

我正在我们的项目中测试ApacheLucene用于基于文本的搜索。不幸的是，我遇到了缺少库的问题。我尝试添加lucene查询，但没有帮助。我做错了什么

错误日志：

Caused by: java.lang.NoClassDefFoundError: org/apache/lucene/search/similarities/DefaultSimilarity
    at org.hibernate.search.spi.SearchIntegratorBuilder.createCleanFactoryState(SearchIntegratorBuilder.java:287)
    at org.hibernate.search.spi.SearchIntegratorBuilder.buildNewSearchFactory(SearchIntegratorBuilder.java:186)
    at org.hibernate.search.spi.SearchIntegratorBuilder.buildSearchIntegrator(SearchIntegratorBuilder.java:117)
    at org.hibernate.search.hcore.impl.HibernateSearchSessionFactoryObserver.sessionFactoryCreated(HibernateSearchSessionFactoryObserver.java:66)
    at org.hibernate.internal.SessionFactoryObserverChain.sessionFactoryCreated(SessionFactoryObserverChain.java:52)
    at org.hibernate.internal.SessionFactoryImpl.<init>(SessionFactoryImpl.java:588)
    at org.hibernate.cfg.Configuration.buildSessionFactory(Configuration.java:1859)
    at org.hibernate.cfg.Configuration.buildSessionFactory(Configuration.java:1930)
    at org.springframework.orm.hibernate4.LocalSessionFactoryBuilder.buildSessionFactory(LocalSessionFactoryBuilder.java:372)
    at org.springframework.orm.hibernate4.LocalSessionFactoryBean.buildSessionFactory(LocalSessionFactoryBean.java:454)
    at org.springframework.orm.hibernate4.LocalSessionFactoryBean.afterPropertiesSet(LocalSessionFactoryBean.java:439)
    at org.springframework.beans.factory.support.AbstractAutowireCapableBeanFactory.invokeInitMethods(AbstractAutowireCapableBeanFactory.java:1633)
    at org.springframework.beans.factory.support.AbstractAutowireCapableBeanFactory.initializeBean(AbstractAutowireCapableBeanFactory.java:1570)
    ... 98 more
Caused by: java.lang.ClassNotFoundException: org.apache.lucene.search.similarities.DefaultSimilarity
    at org.apache.catalina.loader.WebappClassLoaderBase.loadClass(WebappClassLoaderBase.java:1858)
    at org.apache.catalina.loader.WebappClassLoaderBase.loadClass(WebappClassLoaderBase.java:1701)
    ... 111 more

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任何想法，谢谢。：-）

实际上，该类已在中被弃用，当在6.4.2版本中查找该类时，该类已不存在，请参见以下消息：

使用等值行为的类相似性，或考虑切换到BM25相似度，这将成为Lucene 6

中的新缺省值。 见：

• LUCENE-6789:IndexSearcher的默认相似性更改为BM25Similarity。 使用ClassicSimilarity获取旧的向量空间DefaultSimilarity。（罗伯特·缪尔）

---

将lucene核心依赖项降级为5.5.4，或者在代码中使用

ClassicSimility

或

BM25 Similarity

当出现此错误时，您在运行什么？雄猫？你确定lucene内核在类路径中吗？谢谢你的回答，当我添加5.4.1时，我得到的原因是：java.lang.NoSuchFieldError:lucene_3_1。您需要完整的错误日志吗？我没有改变任何代码。谢谢。stacktrace可能会有帮助。我有一个Hibernate orm库，它与lucene冲突，我在mvn dependency:tree中发现了它，并删除了它，因为它不再在project中使用。您能告诉我如何指示库使用由其他依赖项下载的jar吗。谢谢。默认情况下应该是这样的。我能看到它不会发生的唯一情况是，如果您将此依赖项标记为可选的。看到了吗？否则，我需要更仔细地查看您的pom以获得更好的理解

  <!-- https://mvnrepository.com/artifact/org.apache.lucene/lucene-core -->
        <dependency>
            <groupId>org.apache.lucene</groupId>
            <artifactId>lucene-core</artifactId>
            <version>6.4.2</version>
        </dependency>

  @Override
    public void saveIndexes() {
        //Apache Lucene Indexing Directory .txt files
        try {
            //indexing directory
            Path path = Paths.get("/home/akshay/index/");
            Directory directory = org.apache.lucene.store.FSDirectory.open(path);
            IndexWriterConfig config = new IndexWriterConfig(new SimpleAnalyzer());
            IndexWriter indexWriter = new IndexWriter(directory, config);
            indexWriter.deleteAll();
            File f = new File("/home/akshay/textfiles/"); // current directory
            for (File file : f.listFiles()) {
                System.out.println("indexed " + file.getCanonicalPath());
                org.apache.lucene.document.Document doc = new org.apache.lucene.document.Document();
                doc.add(new TextField("path", file.getName(), Field.Store.YES));
                FileInputStream is = new FileInputStream(file);
                BufferedReader reader = new BufferedReader(new InputStreamReader(is));
                StringBuffer stringBuffer = new StringBuffer();
                String line;
                while((line = reader.readLine())!=null){
                    stringBuffer.append(line).append("\n");
                }
                reader.close();
                doc.add(new TextField("contents", stringBuffer.toString(), Field.Store.YES));
                indexWriter.addDocument(doc);
            }
            indexWriter.close();
            directory.close();
        } catch (Exception e) {
            // TODO: handle exception
            e.printStackTrace();
        }
    }

    @Override
    public void searchLucene(String text) {
        //Apache Lucene searching text inside .txt files
        try {
            Path path = Paths.get("/home/akshay/index/");
            Directory directory = FSDirectory.open(path);
            IndexReader indexReader =  DirectoryReader.open(directory);
            IndexSearcher indexSearcher = new IndexSearcher(indexReader);
            QueryParser queryParser = new QueryParser("contents",  new StandardAnalyzer());
            Query query = queryParser.parse(text);
            TopDocs topDocs = indexSearcher.search(query,10);
            System.out.println("totalHits " + topDocs.totalHits);
            for (ScoreDoc scoreDoc : topDocs.scoreDocs) {
                org.apache.lucene.document.Document document = indexSearcher.doc(scoreDoc.doc);
                System.out.println("path " + document.get("path"));
                System.out.println("content " + document.get("contents"));
            }
        } catch (Exception e) {
            // TODO: handle exception
            e.printStackTrace();
        }
    }