Binary to Text and just reverse it to binary using JAVA

Question

I am new in Java.I have changed binary String to text string Using this code.

   StringBuilder contentBuilder = new StringBuilder();
 StringBuffer sb = new StringBuffer();
try {
    BufferedReader in = new BufferedReader(new FileReader("filename.txt"));
    String jitu;
    while ((jitu = in.readLine()) != null) {
        contentBuilder.append(jitu);
    }
    in.close();
} catch (IOException e) {
}
    String binput = contentBuilder.toString();     
     for (int i = 0; i < binput.length()/8; i++)
    {
        int a = Integer.parseInt(binput.substring(8*i,(i+1)*8),2);
       sb.append((char)(a));
    }

Then I want to reverse this text to binary by following code.

      byte[] bytes = binput.getBytes();
  StringBuilder binary = new StringBuilder();
  for (byte b : bytes){
     int val = b;
     for (int i = 0; i < 8; i++){
     binary.append((val & 128) == 0 ? 0 : 1);
     val <<= 1;
     }}

But the problem is When I will getting the output from binary.append(). that is not the same as the the input binary string.I want output same as input. Thanks in advance.

Before you try to do this you should take a look at http://stackoverflow.com/questions/1536054/how-to-convert-byte-array-to-string-and-vice-versa — René Link, Jul 07 '13 at 17:14
I suggest you use StringBuilder instead of StringBuffer. The latter became a legacy class more than ten years ago. — Peter Lawrey, Jul 07 '13 at 20:33

score 0 · Answer 1 · answered Jul 07 '13 at 17:26

If your file really contains binary (as in, not character data), then the way you are reading it in is almost guaranteed to lose data. You are transforming binary to a string using the default charset. On many systems, the default charset is UTF-8. Many binary sequences do not map to a valid unicode character, in those cases if you are interpreting that data as UTF-8, the default behavior is to replace that data with a set replacement character. That means you're going to lose a lot of data.

If you really want to read in binary data as a String (which may well not be a good approach), use a charset which has a mapping for every possible bit sequence (such as Windows-1252) so that you can be sure you won't lose any data.

Binary to Text and just reverse it to binary using JAVA

1 Answers1