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  1. #1
    peuplier is offline Member
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    Default Validate a Zip file with java

    Hello,
    Iam looking for how to validate a zip file in java, I tried for that, to use
    java.sun.com / j2se / 1.4.2 / docs / ap i/ java / util / zip / CheckedInputStream.html , and in the definition of this class, it is said in the documentation :
    An input stream that also maintains a checksum of the data being read. The checksum can then be used to verify the integrity of the input data.
    .
    I tried this code

    Java Code:
    public class Checksumoffile 
    {
    	
    public static void Checkyourfiles(String strfilename)
    {
    	long checksum=0;
    	try {
            // Compute Adler-32 checksum
            CheckedInputStream cis = new CheckedInputStream(
                new FileInputStream(strfilename), new Adler32());
            byte[] tempBuf = new byte[128];
            while (cis.read(tempBuf) >= 0) {
            }
            checksum = cis.getChecksum().getValue();
            
        } catch (IOException e) {
    
    }
        System.out.println("The checksum of file is : " + checksum);
    
    }
    Called by this code
    public static void main(String[] args) {
    // TODO Auto-generated method stub
    try
    {
    Checksumoffile.Checkyourfiles(TestStringTokenizing .strchemin2+"/TestHeadFirsts2.zip");
    }
    catch(Exception exop)
    {
    System.out.println("Problem using your zip "+ exop.getMessage());

    }
    I obtained a checksum = 0 in all cases, even when I have tried with a validate file, and a corrupt file.
    I think there is a problem for me, either my code is wrong, or I did not understand what checksum and Integrity mean. Do Checksum and Integrity mean the same think ? Are they different ?
    I use the almanac java developers 'example availlable here = exampledepot. com / egs / java.util.zip / ChecksumFile.html
    Thx for any help.

    PS: Despite the fact that I posted two links for the first post, I am not a spammer, Iam a java developper, if I put these two links, this is for a purpose to illustrate, and documented my message. I used to post in several java forum as developpez. com, and java.net forum, Glassfish topic
    Last edited by peuplier; 07-10-2009 at 11:21 AM.

  2. #2
    angryboy's Avatar
    angryboy is offline Senior Member
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    Default

    seems to work unless file is not found. then checksum = 0.

    what's this?
    Checksumoffile.Checkyourfiles(TestStringTokenizing .strchemin2+"/TestHeadFirsts2.zip");
    USE CODE TAGS--> [CODE]...[/CODE]
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