Re: How to check two text files have the same content or not?
On Wed, 3 Sep 2008, www wrote:
I need a method to check two text files whether or not have the same
content. The file is small, about 10 lines. But I don't like to compare
them line by line or jam all lines into one line and compare that line.
I thought there should be some way easier.
Then you have another think coming.
There's no way to do this without reading in both files in their entirety.
If you're going to do that, you might as well just compare them
line-by-line or byte-by-byte. What don't you like about doing that?
I googled and have written the following method. But it does not work
correctly. Even the two files have different content, the method returns
true.
Thank you very much for your help.
/**
* Check two files' content are the same or not. The two files are
allowed to be in different locations. If their
* content inside are the same, return true; otherwise, return false.
* <p>
* Note: is possible that the replacement does not alter the checksum?
*/
public static boolean checkTwoFilesEqual(final File fileA, final File
fileB) throws IOException
{
final CheckedInputStream cisA = new CheckedInputStream(new
FileInputStream(fileA), new CRC32());
final CheckedInputStream cisB = new CheckedInputStream(new
FileInputStream(fileB), new CRC32());
if(cisA.getChecksum().getValue() == cisB.getChecksum().getValue())
{
return true;
}
//not equal
return false;
}
A CheckedInputStream only checksums bytes that are read through it. In the
above code, you haven't read any bytes through the streams, so they're
both in their initial states, and so have the same checksum.
You can just do something like this:
InputStream a = new BufferedInputStream(newFileInputStream(fileA)) ;
InputStream b = new BufferedInputStream(newFileInputStream(fileB)) ;
int byteA = 0 ;
int byteB = 0 ;
while ((byteA | byteB) >= 0) {
int byteA = a.read() ;
int byteB = b.read() ;
if (byteA != byteB) return false ;
}
return byteA == byteB ;
tom
--
To a great extent, it's about 'Am I going to go crazy and smash things
as I'm trying to fix them?' -- Bill Jemas, on the Hulk