Replace an existing file, length issue

Question

I have a strange issue, when replacing a file by another. This code works well the first time :

String fileContent = "test";    

File file = new File(Environment.getExternalStorageDirectory() + "/myApp/text.txt");
    file.getParentFile().mkdirs();
    if (file.exists())
        file.delete();

    try {
        FileOutputStream fileOutputStream = new FileOutputStream(filePath);
        BufferedOutputStream bufferedOutputStream = new BufferedOutputStream(fileOutputStream);

        bufferedOutputStream.write(fileContent.getBytes());

        bufferedOutputStream.close();
        fileOutputStream.close();

    } catch (Exception exception) {
        exception.printStackTrace();
    }

It creates a file with this content :

test

Then I execute the code again, replacing the "test" string by a longer string :

String fileContent = "admiral";

It removes the old file, create a new one, BUT it only write the 4 first characters :

admi

Finally, if I replace the content by a shorter string ("be", it creates a corrupted file :

be\00\00

But if I remove the file manually, it works... Very strange...

SOLVED : The problem was, gedit's cache! :s, by the way thx all for your help ! :)

have you tried adding `bufferedOutputStream.flush()` after `write`? — Pier Giorgio Misley, Nov 20 '17 at 14:26

score 0 · Answer 1 · answered Nov 20 '17 at 14:04

0

Try to overwrite the content using this :

FileOutputStream fileOutputStream = new FileOutputStream(filePath, false);

answered Nov 20 '17 at 14:04

diegoveloper

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dalla92 · Answer 2 · 2017-11-20T14:37:18.090

I don't understand why you need to use BufferedOutputStream... Just try to write using FileOutputStream in this way:

String fileContent = "test";    
File file = new File(Environment.getExternalStorageDirectory() + "/myApp/text.txt");
    file.getParentFile().mkdirs();
    if (file.exists())
        file.delete();

    try {
        FileOutputStream fileOutputStream = new FileOutputStream(filePath);

        fileOutputStream.write(fileContent.getBytes());

        fileOutputStream.close();

    } catch (Exception exception) {
        exception.printStackTrace();
    }

Reference: this question

score 0 · Answer 3 · answered Nov 20 '17 at 14:37

First be aware that String.getBytes() without the optional parameter for the charset, takes that of the current platform.

For appending one would need to call:

FileOutputStream fileOutputStream = new FileOutputStream(filePath, true);

In your case you want to replace the contents, and your construct does that already. Remove delete as that gives better system behavior.

Then the final problem writing only 4 bytes.

   bufferedOutputStream.write(fileContent.getBytes());

As if the old file length (of "test" = 4 bytes) was used to write the new content. I cannot explain that, so maybe the removal of delete might cause the bug to disappear.

What might be the case, is that the file is opened elsewhere.

Replace an existing file, length issue

3 Answers3