package sup.orange.learn;import java.io.FileInputStream;import java.io.IOException;import java.security.MessageDigest;import java.security.NoSuchAlgorithmException;/** * Created by re-x on 11/4/14. */public class HashFileTest {    public static void main(String[] args) throws IOException, NoSuchAlgorithmException {        boolean result = verifyChecksum("/home/re-x/Downloads/linux-1.0.tar.bz2", "4b3de322714d911c8bb46ceda2dbf541e6ab24f4");        System.out.println("Does the file‘s checksum matches the expected one? " + result);    }    /**     * Verifies file‘s SHA1 checksum.     * @param file, filepath and namd of a file that is to be verified.     * @param testChecksum, the expected checksum.     * @return true if the expeceted SHA1 checksum matches the file‘s SHA1 checksum; false otherwise     * @throws java.security.NoSuchAlgorithmException     * @throws java.io.IOException     */    public static boolean verifyChecksum(String file, String testChecksum) throws NoSuchAlgorithmException, IOException {        MessageDigest messageDigest = MessageDigest.getInstance("SHA1");        FileInputStream fis = new FileInputStream(file);        byte[] data = http://www.mamicode.com/new byte[1024];        int read = 0;        while ((read = fis.read(data)) != -1) {            messageDigest.update(data, 0, read);        }        byte[] hashBytes = messageDigest.digest();        StringBuffer sb = new StringBuffer();        for (int i = 0; i < hashBytes.length; i++) {            sb.append(Integer.toString((hashBytes[i] & 0xff) + 0x100, 16).substring(1));        }        String fileHash = sb.toString();        System.out.println(file+" sha1 is: "+fileHash);        return fileHash.equals(testChecksum);    }}