File appending in servlet

Question

The following code appends data to the given file in java application. But when put this code in servlet, the file becomes empty. Why this?

try {            
  OutputStreamWriter writer = new OutputStreamWriter(new FileOutputStream("C:\\root.properties", true), "UTF-8");
  BufferedWriter fbw = new BufferedWriter(writer);
  String s = "root.label.1130.2=قسيمات";      
  fbw.write(new String(s.getBytes("iso-8859-1"), "UTF-8"));
  fbw.newLine();
  fbw.close();
} catch (Exception e) {
  System.out.println("Error: " + e.getMessage());
}

score 2 · Answer 1 · answered Jan 10 '12 at 10:44

2

The string does contain non-ISO-8859-1 characters after the equals sign. You may want to check that the Java compilation accepts UTF-8 input, i.e. javac -encoding UTF-8. Also, replace "iso-8859-1" with "UTF-8" in getBytes().

See http://illegalargumentexception.blogspot.com/2009/05/java-rough-guide-to-character-encoding.html#javaencoding_sourcefiles for a nice write-up and other ways to encode the constant string.

answered Jan 10 '12 at 10:44

mgaert

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@magaert:I get the correct output when I create a new file. But while appending there are problems in writing and in encoding. – skmaran.nr.iras Jan 10 '12 at 11:25
Oh, that focuses the question a bit. Also, you are aware that Java properties are usually ISO-8859-1 (with character quoting)? Are you sure you can read the UTF-8 properties file? See http://stackoverflow.com/a/3040771/1037626 – mgaert Jan 10 '12 at 11:32

Peter Lawrey · Answer 2 · 2012-01-10T12:00:37.290

1

Are you sure you are seeing any exception which might be thrown? Perhaps your servlet doesn't have permission to write to the file. I would try to debug your program to see what happens when this code is run.

What you are doing will corrupt many of the characters, but you should still get a file.

When I run this code I get a file with

root.label.1130.2=??????

which is what you would expect to get.

If I run this code

PrintWriter pw = new PrintWriter(new OutputStreamWriter(new FileOutputStream("root.properties", true), "UTF-8"));
String s = "root.label.1130.2=قسيمات";
pw.println(s);
pw.close();

BufferedReader br = new BufferedReader(new InputStreamReader(new FileInputStream("root.properties"), "UTF-8"));
String line;
while ((line = br.readLine()) != null) {
    for (int i = 0; i < line.length(); i++) {
        char ch = line.charAt(i);
        if (ch >= ' ' && ch < 127)
            System.out.print(ch);
        else
            System.out.printf("\\u%04x", (int) ch);
    }
    System.out.println();
}

prints the following, showing that the Arabic characters have not been mangled.

root.label.1130.2=\u0642\u0633\u064a\u0645\u0627\u062a

the file now contains

root.label.1130.2=قسيمات

as expected.

edited Jan 10 '12 at 12:00

answered Jan 10 '12 at 10:29

Peter Lawrey

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Are you sure that the question marks are not present in the Servlet source code file after you copied-and-pasted the snippet? – mgaert Jan 10 '12 at 10:40
1

@Peter Lawrey:I get the correct output when I create a new file. But while appending there are problems in writing and in encoding. – skmaran.nr.iras Jan 10 '12 at 11:32
@1355 I can't see how your encoding would ever work. Have you tried the code I suggested? This does work when appending (as I have shown) – Peter Lawrey Jan 10 '12 at 11:34
@Peter : Unfortunately that also does not work for me even in simple java aaplication. It writes as "root.label.1130.2=??????" – skmaran.nr.iras Jan 10 '12 at 11:47
@1355 and you are reading as UTF-8 in a console which supports Arabic characters. What do you see if you open the file in wordpad? – Peter Lawrey Jan 10 '12 at 11:50
@1355 Try the example I have given now. – Peter Lawrey Jan 10 '12 at 12:00
@peter : now also the same. file losts its content also. I am using netbeans for development. – skmaran.nr.iras Jan 10 '12 at 12:06

File appending in servlet

2 Answers2