Java 對文件進行 CRC32 校驗

import java.util.zip.CheckedInputStream;
import java.util.zip.CRC32;
import java.io.File;
import java.io.FileInputStream;
import java.io.FileNotFoundException;
import java.io.IOException;

/**


Used to provide an example of how to calculate the checksum of a file using
the CRC-32 checksum engine.
*
@version 1.0
@author  Jeffrey M. Hunter  (jhunter@idevelopment.info)
@author  <a href="http://www.idevelopment.info">http://www.idevelopment.info


*/
public class ChecksumCRC32 {

private static void doChecksum(String fileName) {

    try {

        CheckedInputStream cis = null;
        long fileSize = 0;
        try {
            // Computer CRC32 checksum
            cis = new CheckedInputStream(
                    new FileInputStream(fileName), new CRC32());

            fileSize = new File(fileName).length();

        } catch (FileNotFoundException e) {
            System.err.println("File not found.");
            System.exit(1);
        }

        byte[] buf = new byte[128];
        while(cis.read(buf) >= 0) {
        }

        long checksum = cis.getChecksum().getValue();
        System.out.println(checksum + " " + fileSize + " " + fileName);

    } catch (IOException e) {
        e.printStackTrace();
        System.exit(1);
    }


}


/**
 * Sole entry point to the class and application.
 * @param args Array of String arguments.
 */
public static void main(String[] args) {

    if (args.length != 1) {
        System.err.println("Usage: java ChecksumCRC32 filename");
    } else {
        doChecksum(args[0]);
    }

}


}</pre>