Dumping a Java StringBuilder to File

Question

What is the most efficient/elegant way to dump a StringBuilder to a text file?

You can do:

outputStream.write(stringBuilder.toString().getBytes());
         


        

Answer 1

Well, if the string is huge, toString().getBytes() will create duplicate bytes (2 or 3 times). The size of the string.

To avoid this, you can extract chunk of the string and write it in separate parts.

Here is how it may looks:

final StringBuilder aSB = ...;
final int    aLength = aSB.length();
final int    aChunk  = 1024;
final char[] aChars  = new char[aChunk];

for(int aPosStart = 0; aPosStart < aLength; aPosStart += aChunk) {
    final int aPosEnd = Math.min(aPosStart + aChunk, aLength);
    aSB.getChars(aPosStart, aPosEnd, aChars, 0);                 // Create no new buffer
    final CharArrayReader aCARead = new CharArrayReader(aChars); // Create no new buffer

    // This may be slow but it will not create any more buffer (for bytes)
    int aByte;
    while((aByte = aCARead.read()) != -1)
        outputStream.write(aByte);
}

Hope this helps.