Question

i m new in java….i m trying to read a text file using file input stream. i m reading text line by line and set as a string.. now i want to convert string into byte. but i m getting a number format exception.. please help me to solve this problem.

FileInputStream fstream = new FileInputStream("C:/Users/data.txt");

          DataInputStream in = new DataInputStream(fstream);
          BufferedReader br = new BufferedReader(new InputStreamReader(in));
          byte[] bytes = null;
          String str;
          int i=0;

          while ((str = br.readLine()) != null) 
          {

              bytes[i] = Byte.parseByte(str,16);
              i++;
          }

          in.close();

Answer 1

Try

byte[] bytes = str.getBytes();

instead of

bytes[i] = Byte.parseByte(str,16);

Also I recommend to specify encoding for InputStreamReader:

BufferedReader br = new BufferedReader(new InputStreamReader(in, "UTF-8"));

Keep in mind that Java String length and internal representation would not be same to C.