How do I go from byte to int?

Question

I am writing a program which reads a file in, transforms it into a byte array and then extracts information out of the byte array. One of these bits of information is an integer. I am having great trouble actually transforming the byte[] containing the bytes for the integer actually into the integer!
I've Googled and looked around forums and I'm just not sure why it's not working. :s
This is what I have so far:
     private int bytesToInt(byte[] b) {
          int bLen = b.length;
          System.out.println("length: " + bLen);
          int result;
          switch (bLen) {
               case 1: result = (int)b[0] & 0xFF; break;
               //case 2: return b[0]
               default: result = 999; break;
          } // switch
          return result;
     } // bytesToInt()When i run it at the moment, with the integer 5 in the file, it returns 53 instead.. Any help would be much appreciated!

Answer 1

I seem to be going round in circles with this!! I've tried various ways and i'm just not getting it. :s
This is what i've tried:
     private int bytesToInt(byte[] b) throws IOException {
          // takes the bytes specifying the win amount, casts to char and parses to int
          int bLen = b.length;
          char[] ch = null;
          int result = 0;
          // can take numbers up to 999
          switch (bLen) {
               case 1: ch[0] = (char)(b[0] + '0');
               result = Character.digit(ch[0], 10);
               break;
               // case 2: ch[0] = (char)(b[0] + '0'); ch[1] = (char)(b[1] + '0'); break;
               // case 3:  ch[0] = (char)(b[0] + '0'); ch[1] = (char)(b[1] + '0'); ch[2] = (char)(b[2] + '0'); break;
               default: result = 0; break;
          } // switch
          return result;
     } // bytesToInt()which gave me the error:
Exception in thread "main" java.lang.NullPointerException
     at lod.LODMapLoader2.bytesToInt(LODMapLoader2.java:112)
     at lod.LODMapLoader2.getWinAmount(LODMapLoader2.java:99)
     at lod.LODMapLoader2.main(LODMapLoader2.java:181)
Vanessa-Clarkes-MacBook:src vrc20$ javac lod/LODMapLoader2.java
Vanessa-Clarkes-MacBook:src vrc20$ java lod/LODMapLoader2 testFile
and so then i tried to simplify it and only consider if i was to be given one int..
     private int bytesToInt(byte[] b) throws IOException {
          // takes the bytes specifying the win amount, casts to char and parses to int
          int bLen = b.length;
          char ch;
          int result = 0;
          // can take numbers up to 9
          ch = (char)(b[0] + '0');
          result = (int)ch - '0';
          return result;
     } // bytesToInt()This ended up giving me 53 again. I'm feeling slightly frustrated.. What have I missed?