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POShouldn't the content of a file remain unaltered if I read it byte-by-byte?
 

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  1. POShouldn't the content of a file remain unaltered if I read it byte-by-byte?
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    <p>Why does the following code alter "öäüß"? (I am using it to split big files into multiple small ones...)</p> <pre><code>InputStream is = new BufferedInputStream(new FileInputStream(file)); File newFile; BufferedWriter bw; newFile = new File(filePathBase + "." + String.valueOf(files.size() + 1) + fileExtension); files.add(newFile); bw = new BufferedWriter(new FileWriter(newFile)); try { byte[] c = new byte[1024]; int lineCount = 0; int readChars = 0; while ( ( readChars = is.read(c) ) != -1 ) for ( int i=0; i&lt;readChars; i++ ) { bw.write(c[i]); if ( c[i] == '\n' ) if ( ++lineCount % linesPerFile == 0 ) { bw.close(); newFile = new File(filePathBase + "." + String.valueOf(files.size() + 1) + fileExtension); files.add(newFile); bw = new BufferedWriter(new FileWriter(newFile)); } } } finally { bw.close(); is.close(); } </code></pre> <p>My understanding of character encoding is that everything should remain the same as long as i keep each byte the same. Why does this code alter bytes?</p> <p>Thanks a bunch in advance~</p> <p>==================== SOLUTION ====================</p> <p>The mistake is that <code>FileWriter</code> interprets bytes and shouldn't be used to just output plain bytes, thanks @meriton and @Jonathan Rosenne. Just changing everything to <code>BufferedOutputStream</code> doesn't do it though, since <code>BufferedOutputStream</code> is too slow! I ended up improving my file split-and-copy code to include a bigger read-array size and only <code>write()</code> when necessary ...</p> <pre><code>File newFile = new File(filePathBase + "." + String.valueOf(files.size() + 1) + fileExtension); files.add(newFile); InputStream iS = new BufferedInputStream(new FileInputStream(file)); OutputStream oS = new FileOutputStream(newFile); // BufferedOutputStream wrapper toooo slow! try { byte[] c; if ( linesPerFile &gt; 65536 ) c = new byte[65536]; else c = new byte[1024]; int lineCount = 0; int readChars = 0; while ( ( readChars = iS.read(c) ) != -1 ) { int from = 0; for ( int idx=0; idx&lt;readChars; idx++ ) if ( c[idx] == '\n' &amp;&amp; ++lineCount % linesPerFile == 0 ) { oS.write(c, from, idx+1 - from); oS.close(); from = idx+1; newFile = new File(filePathBase + "." + String.valueOf(files.size() + 1) + fileExtension); files.add(newFile); oS = new FileOutputStream(newFile); } oS.write(c, from, readChars - from); } } finally { iS.close(); oS.close(); } </code></pre>
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    1. PO
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      1. PTAnswer
    1. This table or related slice is empty.
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    1. USdotwin
    1. USdotwin
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    1. This table or related slice is empty.
    1. This table or related slice is empty.
    1. This table or related slice is empty.
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    3. PO
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    1. This table or related slice is empty.
    1. COWhat are the values of the fileExtension variable?
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      1. POShouldn't the content of a file remain unaltered if I read it byte-by-byte?
      1. USlinski
    2. CO".csv" for example.
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      1. POShouldn't the content of a file remain unaltered if I read it byte-by-byte?
      1. USdotwin
 

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