Issue while reading special characters from file

Question

I am facing an issue while reading a file with special characters. My .txt file has data:

I am reading this file using following code:

StringBuilder sBuilderString = new StringBuilder();

for (int n; (n = loInputStream.read()) != -1;) {
    sBuilderString.append((char)n);
}

This string is now again used to write a file, the issue is that when i write the file, one of these two characters is replaced by some other special character.

How can i write code, which is able to read all the special characters and write that to another file?

score 2 · Accepted Answer · answered Jun 26 '11 at 09:03

2

You have issues with the encoding of your characters. The call to '(char) n) will effectively transform byte n into a character using the default character encoding of your system, which might differ from the encoding of your source file.

One way to avoid that is to wrap your InputStream in a CharacterInputStream, where you can specify the character encoding:

Reader reader = new InputStreamReader( loInputStream, "UTF-8");

You can then proceed to read your stream into your StringBuilder. I would also recommend to wrap your reader with a bufferedReader to improve performance with blocking IO streams.

Reader reader = new BufferedReader(new InputStreamReader( loInputStream, "UTF-8"));

answered Jun 26 '11 at 09:03

maasg

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@maasg: How can i get encoding format of my file (I am trying to read image stream, .jpg file) – Ankit Jun 26 '11 at 09:06
1

@Ankit: that is binary data, not text, so don't treat it as text. It doesn't make sense to put it on a `StringBuilder`. – ninjalj Jun 26 '11 at 09:12
@Ankit as @ninjalj said, don't treat binary data as chars. You need to preserve is as bytes all the way. Look into nio.ByteBuffer – maasg Jun 26 '11 at 09:17
@Ankit btw, your question "My .txt file has data..." didn't hint to the jpg format. Something to keep in mind next time. – maasg Jun 26 '11 at 09:54
@maasg & @ninjalj : Thanks for your effort, the reason why I want to read the stream as String is that I want to send this stream String in post request for REST, where it can be recreated as image again. I can not directly accept the stream for recreation of image. – Ankit Jun 26 '11 at 10:31
@maasg: I wrote text file had this special characters because i didn't wanted to make the question complex. Anyways, will keep in mind from next time. – Ankit Jun 26 '11 at 10:32
@Ankit: for xfer of binary as text, look for Base64 encoding. – maasg Jun 26 '11 at 11:01
@maasg: Can you please elaborate.. Thanks – Ankit Jun 26 '11 at 11:42
@Ankit: Base64 is typically used to convert binary formats into printable characters for text-based transfer. A common use are MIME attachments to email, etc. Apache has an impl here: http://goo.gl/LTnQv Don't know yr requirements to extends this more. Ask another question w/more details if you want. Comments are more for clarifications on current question. – maasg Jun 26 '11 at 13:02

score 1 · Answer 2 · answered Jun 26 '11 at 08:50

1

Use InputStreamReader and specify encoding which is used in the file.

answered Jun 26 '11 at 08:50

Jarek Potiuk

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Issue while reading special characters from file

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