读取文本字符串统计单个字符串出现的次数

版权声明： https://blog.csdn.net/qq_36907589/article/details/83030529

@Test
    public void teht(){
         String result = "";
         try {
             FileInputStream file = new FileInputStream("D:/test/e.txt");
             BufferedInputStream Bfile = new BufferedInputStream(file);
             byte[] b = new byte[1024];
             int bytesRead=0;
             while((bytesRead=Bfile.read(b))!=-1){
                 result+= new String(b,0,bytesRead);
             }
             System.out.println("字符串"+result);
         } catch (FileNotFoundException e) {
             e.printStackTrace();
         } catch (IOException e) {
             e.printStackTrace();
         }
         String[] arr = result.split("");
        // String[] arr = result.split(" ");
        String s = Arrays.toString(arr);
        System.out.println("S=="+s);
         System.out.println(arr.length);
         Map<String, Integer> map = new HashMap<>();
         for (String str : arr) {
             Integer num = map.get(str);
             map.put(str, num == null ? 1 : num + 1);
         }
         Set set = map.entrySet();
         Iterator it = set.iterator();
         System.out.println("---------------------------------------------");
         System.out.println("方法一 ：");
         while (it.hasNext()) {
             Map.Entry<String, Integer> entry = (Map.Entry<String, Integer>) it.next();
             System.out.println("单词 " + entry.getKey() + " 出现次数 : " + entry.getValue());
         }
         System.out.println("---------------------------------------------");
         System.out.println("方法二 ：");
         Iterator it01 = map.keySet().iterator();
         while (it01.hasNext()) {
             Object key = it01.next();
             System.out.println("单词 " + key + " 出现次数 : " + map.get(key));
         }

     }

第二种方法：

@Test
    public void teht11(){
        String result = "";
        try {
            FileInputStream file = new FileInputStream("D:/test/e.txt");
            BufferedInputStream Bfile = new BufferedInputStream(file);
            byte[] b = new byte[1024];
            int bytesRead=0;
            while((bytesRead=Bfile.read(b))!=-1){
                result+= new String(b,0,bytesRead);
            }
            System.out.println("字符串"+result);
        } catch (FileNotFoundException e) {
            e.printStackTrace();
        } catch (IOException e) {
            e.printStackTrace();
        }
        char[] chars = result.toCharArray();
        HashMap<String, Integer> map = new HashMap<>();
        for (Character c : chars) {
            if(!map.containsKey(c.toString())){
                map.put(c.toString(),1);
            }else {
                map.put(c.toString(),map.get(c.toString())+1);
            }
        }
        for (String key: map.keySet() ) {
            System.out.println(key+"=出现="+map.get(key));
        }

    }