hashutil.java

spring+acegi编写的网上书城

package net.livebookstore.util;

import java.security.*;

/**
 * Use String MD5.toMD5(String str) to get the digest of the String.
 * 
 * @author Xuefeng
 */
public final class HashUtil {

    private static final char[] HEX = {'0', '1', '2', '3', '4', '5', '6', '7', '8', '9', 'a', 'b', 'c', 'd', 'e', 'f'};

    private static String toHexString(byte[] bytes) {
        int length = bytes.length;
        StringBuffer sb = new StringBuffer(length * 2);
        int x = 0;
        int n1 = 0, n2 = 0;
        for(int i=0; i<length; i++) {
            if(bytes[i]>=0)
                x = bytes[i];
            else
                x= 256 + bytes[i];
            n1 = x >> 4;
            n2 = x & 0x0f;
            sb = sb.append(HEX[n1]);
            sb = sb.append(HEX[n2]);
        }
        return sb.toString();
    }

    /**
     * Make MD5 diaguest.
     * 
     * @param str Original String.
     * @return MD5-String.
     */
    public static String toMD5(String str) {
        try {
            MessageDigest md = MessageDigest.getInstance("MD5");
            byte[] buf = md.digest(str.getBytes());
            return toHexString(buf);
        }
        catch (NoSuchAlgorithmException e) {
            throw new RuntimeException(e);
        }
    }

}