public static void fileRevise(File file) throws IOException {    Reader reader=new BufferedReader(new FileReader(file));    //讀取的數據用內存為中介，存取，如建立一個集合    int len;    char[] charArray=new char[1024];    //集合用于儲存讀取的數據    List<Character> list=new ArrayList<>();//char 類型的集合，儲存char[]讀取的數據    while ((len=reader.read(charArray))!=-1){      for (int i = 0; i <len ; i++) {        list.add(charArray[i]);//char->string      }    }    char[] newArray=new char[list.size()];    for (int i = 0; i <list.size() ; i++) {      newArray[i]=list.get(i);    }    Arrays.sort(newArray);    Writer write=new BufferedWriter(new FileWriter(file));    write.write(newArray);    //關閉流     reader.close();    write.close();  }

//用字符緩沖流的方法readline()讀取，用字符串緩存，將字符串轉為字符數組重新寫入  public static void fileRevise2(File file) throws IOException {    Reader reader=new BufferedReader(new FileReader(file));    StringBuilder sb=new StringBuilder();    String str;    while ((str=((BufferedReader) reader).readLine())!=null){      sb.append(str);    }    System.out.print(sb);    char[] cArray=sb.toString().toCharArray();//    Arrays.sort(cArray);    reader.close();    Writer write=new BufferedWriter(new FileWriter(file));    write.write(cArray);    write.close();  }