Java Convert UTF-8 Text File to Cp1250

Question

I'm trying to convert UTF-8 text file into Windows-1250. I'm using Java 6 API.

I've used code below, but the result is definitely not a Cp1250.

import java.io.*; 

public class testing {
    public static void main (String[] args) throws IOException {   

        InputStream  input = null;
        OutputStreamWriter output = null;   

        File destinationFile = new File("C:\\test\\Cp1250.txt");   

        try {      
            input = new FileInputStream("C:\\test\\utf-8.txt");
            output = new OutputStreamWriter(new FileOutputStream(destinationFile), "Windows-1250");

            while (input.read() != -1) {
                output.write(input.read());
            }

        } catch (Exception e) {
            e.printStackTrace(); 
        } finally {
            input.close();
            output.close(); 
        }      
    }
}

Please explain more clearly what is going wrong. What is the output and what have you done to try and fix your problem? — bknopper, Mar 13 '14 at 15:47
**DO NOT** catch `Exception`... This captures all unchecked exceptions as well. Catch more specific ones. — fge, Mar 13 '14 at 15:56

score 4 · Accepted Answer · answered Mar 13 '14 at 15:37

You need an InputStreamReader, which knows that the data from the FileInputStream must be interpreted with the UTF-8 charset.

Here is an example. I have omitted the closing of the resources for brevity.

    FileInputStream input = new FileInputStream(file);
    InputStreamReader reader = new InputStreamReader(input, "utf-8");
    FileOutputStream output = new FileOutputStream(destinationFile);
    OutputStreamWriter writer = new OutputStreamWriter(output, "Windows-1250");

    int read = reader.read();
    while (read != -1)
    {
        writer.write(read);
        read = reader.read();
    }

And another thing: In your while loop you have two calls to input.read, but you call output.write() only once. This means you only write half of the bytes which you have read.

As I said, I omitted the closing of the resources, you still need to do that. The file is probably empty as the FileOutputStream has not been flushed. — Steven Pessall, Mar 13 '14 at 16:10
Have you closed all resources? Including the reader and writer? I just tested it and the destinationFile actually remains empty when you only close the output stream but not the writer. — Steven Pessall, Mar 13 '14 at 16:25

fge · Answer 2 · 2014-03-13T16:07:38.627

Here is how you do it when using Java 7:

final Path src = Paths.get("C:\\test\\utf-8.txt");
final Path dst = Paths.get("C:\\test\\Cp1250.txt");

try (
    BufferedReader reader = Files.newBufferedReader(src, StandardCharsets.UTF_8);
    BufferedWriter writer = Files.newBufferedWriter(dst, 
        Charset.forName("windows-1252"));
) {
    String line;
    while ((line = reader.readLine()) != null) {
        writer.write(line);
        writer.newLine();
    }
    writer.flush();
}

Java Convert UTF-8 Text File to Cp1250

2 Answers2