lucene 统计单词次数(词频tf)并进行排序

 public class WordCount {
     static Directory directory;
     // 创建分词器
     static Analyzer analyzer = new IKAnalyzer();
     static IndexWriterConfig config = new IndexWriterConfig(analyzer);
     static IndexWriter writer;
     static IndexReader reader;
     static {
         // 指定索引存放目录以及配置参数
         try {
             directory = FSDirectory.open(Paths.get("F:/luceneIndex"));
             writer = new IndexWriter(directory, config);
         } catch (IOException e) {
             e.printStackTrace();
         }
     }

     public static void main(String[] args) {
         indexCreate();
         Map<String, Long> map = getTotalFreqMap();
         Map<String, Long> sortMap = sortMapByValue(map);
         Set<Entry<String, Long>> entrySet = sortMap.entrySet();
         Iterator<Entry<String, Long>> iterator = entrySet.iterator();
         while (iterator.hasNext()) {
             Entry<String, Long> entry = iterator.next();
             System.out.println(entry.getKey() + "----" + entry.getValue());
         }

     }

     /**
      * 创建索引
      */
     public static void indexCreate() {
         // 文件夹检测(创建索引前要保证目录是空的)
         File file = new File("f:/luceneIndex");
         if (!file.exists()) {
             file.mkdirs();
         } else {
             try {
                 file.delete();
             } catch (Exception e) {
                 e.printStackTrace();
             }
         }

         // 将采集的数据封装到Document中
         Document doc = new Document();
         FieldType ft = new FieldType();
         ft.setIndexOptions(IndexOptions.DOCS_AND_FREQS);
         ft.setStored(true);
         ft.setStoreTermVectors(true);
         ft.setTokenized(true);
         // ft.setStoreTermVectorOffsets(true);
         // ft.setStoreTermVectorPositions(true);

         // 读取文件内容(小文件,readFully)
         File content = new File("f:/qz/twitter.txt");
         try {
             byte[] buffer = new byte[(int) content.length()];
             IOUtils.readFully(new FileInputStream(content), buffer);
             doc.add(new Field("twitter", new String(buffer), ft));
         } catch (Exception e) {
             e.printStackTrace();
         }

         // 生成索引
         try {
             writer.addDocument(doc);
             // 关闭
             writer.close();

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

     /**
      * 获得词频map
      *
      * @throws ParseException
      */
     public static Map<String, Long> getTotalFreqMap() {
         Map<String, Long> map = new HashMap<String, Long>();
         try {
             reader = DirectoryReader.open(directory);
             List<LeafReaderContext> leaves = reader.leaves();
             for (LeafReaderContext leafReaderContext : leaves) {
                 LeafReader leafReader = leafReaderContext.reader();

                 Terms terms = leafReader.terms("twitter");

                 TermsEnum iterator = terms.iterator();

                 BytesRef term = null;

                 while ((term = iterator.next()) != null) {
                     String text = term.utf8ToString();
                     map.put(text, iterator.totalTermFreq());
                 }

             }
             reader.close();
             return map;
         } catch (IOException e) {
             e.printStackTrace();
         }
         return null;
     }

     /**
      * 使用 Map按value进行排序
      *
      * @param map
      * @return
      */
     public static Map<String, Long> sortMapByValue(Map<String, Long> oriMap) {
         if (oriMap == null || oriMap.isEmpty()) {
             return null;
         }
         Map<String, Long> sortedMap = new LinkedHashMap<String, Long>();

         List<Map.Entry<String, Long>> entryList = new ArrayList<Map.Entry<String, Long>>(oriMap.entrySet());
         Collections.sort(entryList, new MapValueComparator());

         Iterator<Map.Entry<String, Long>> iter = entryList.iterator();
         Map.Entry<String, Long> tmpEntry = null;
         while (iter.hasNext()) {
             tmpEntry = iter.next();
             sortedMap.put(tmpEntry.getKey(), tmpEntry.getValue());
         }
         return sortedMap;
     }
 }

 class MapValueComparator implements Comparator<Map.Entry<String, Long>> {

     @Override
     public int compare(Entry<String, Long> me1, Entry<String, Long> me2) {
         if (me1.getValue() == me2.getValue()) {
             return ;
         }
         return me1.getValue() > me2.getValue() ? - : ;
         // return me1.getValue().compareTo(me2.getValue());
     }
 }

map排序代码https://www.cnblogs.com/zhujiabin/p/6164826.html