如何在 utf-8 中读写这个？

Question

I was getting an error io.MalformedByteSequenceException: Invalid byte 2 of 2-byte UTF-8 sequence

The solution is to read and write file in UTF-8.

My code is:

InputStream input = null;
OutputStream output = null;
OutputStreamWriter bufferedWriter = new OutputStreamWriter( output, "UTF8");
input = new URL(url).openStream();
output = new FileOutputStream("DirectionResponse.xml");
byte[] buffer = new byte[1024];
for (int length = 0; (length = input.read(buffer)) > 0;) {
   output.write(buffer, 0, length);
}
BufferedReader br = new BufferedReader(new FileReader("DirectionResponse.xml" ));
FileWriter fstream = new FileWriter("ppre_DirectionResponse.xml");
BufferedWriter out = new BufferedWriter(fstream);

I'm reading a url and writing it to a file DirectionResponse.xml . Then reading DirectionResponse.xml and writing the same as *ppre_DirecionResponse.xml* for processing.

How do I change this so that reading and writing is done in UTF-8?

Answer 1

First, you need to call output.close() (or at least call output.flush() ) before you reopen the file for input. That's probably the main cause of your problems.

Then, you shouldn't use FileReader or FileWriter for this because it always uses the platform-default encoding (which is often not UTF-8). From the docs for FileReader :

The constructors of this class assume that the default character encoding and the default byte-buffer size are appropriate.

You have the same problem when using a FileWriter . Replace this:

BufferedReader br = new BufferedReader(new FileReader("DirectionResponse.xml" ));

with something like this:

BufferedReader br = new BufferedReader(new InputStreamReader(
    new FileInputStream("DirectionResponse.xml"), "UTF-8"));

and similarly for fstream .

Answer 2

Read and Write UTF-8 File in Java

I see you are writing in utf-8 but not specifically reading in utf-8. Follow the example I've provided in the link.

try {
   Reader reader =
      new InputStreamReader(
         new FileInputStream(args[0]),"UTF-8");
   BufferedReader fin = new BufferedReader(reader);
   Writer writer =
      new OutputStreamWriter(
         new FileOutputStream(args[1]), "UTF-8");
   BufferedWriter fout = new BufferedWriter(writer);
   String s;
   while ((s=fin.readLine())!=null) {
      fout.write(s);
      fout.newLine();
   }

            //Remember to call close. 
            //calling close on a BufferedReader/BufferedWriter 
            // will automatically call close on its underlying stream 
   fin.close();
   fout.close();
} catch (IOException e) {
   e.printStackTrace();
}