读取文件并写入到另一个过滤

  FileReader fileReader = new FileReader("E:\\workSpace\\Project\\day37\\src\\a.txt");
    FileWriter fileWriter = new FileWriter("F:\\b.txt");
    List<Character> list=new ArrayList<>();
    char[] chars = new char[1024 * 8];

    int len;
    while ((len=fileReader.read(chars))!=-1){
        for (int i = 0; i <len ; i++) {
            list.add(chars[i]);
        }
        //去重
        List<Character> collect = list.stream().distinct().sorted((o1, o2) -> o1-o2).collect(Collectors.toList());
        for (Character character : collect) {
            fileWriter.write(character);
        }

    }
    fileWriter.close();
}