Question

i want to convert the content to utf-8 charset before i return the string in following method:

public static String getContentResult(URL url) throws IOException{
    InputStream in = url.openStream();
    StringBuilder sb = new StringBuilder();

    byte [] buffer = new byte[4096];

    while(true){
        int byteRead = in.read(buffer);
        if(byteRead == -1)
            break;
        for(int i = 0; i < byteRead; i++){
            sb.append((char)buffer[i]);
        }
    }
    in.close();
    return sb.toString();
}

How can i do that?

Thanks!

Answer 1

You don’t want to convert to UTF-8. You want (I believe) to interpret the incoming stream of data as UTF-8.

Options:

• Create an InputStreamReader wrapping your incoming stream, specifying UTF-8, and read blocks of characters at a time, appending to a StringBuilder

  StringBuilder builder = new StringBuilder();
  char[] buffer = new char[4096];
  InputStreamReader reader = new InputStreamReader(in, "UTF-8");
  int charsRead;
  while ((charsRead = reader.read(buffer)) != -1) {
      builder.append(buffer, 0, charsRead);
  }
  

• Use Guava to read the whole data as a byte array, then convert it in one go:

  byte[] data = BytesStreams.toByteArray(in);
  return new String(data, Charsets.UTF_8);
  

In either case, you should use a finally block to close the stream, so that you close it even if an exception is thrown.