Java之MD5演算法實現

import java.security.MessageDigest;import java.security.NoSuchAlgorithmException;public class MD5 {        // 全域數組    private final static String[] strDigits = { "0", "1", "2", "3", "4", "5",            "6", "7", "8", "9", "a", "b", "c", "d", "e", "f" };    public MD5() {    }    // 返回形式為數字跟字串    private static String byteToArrayString(byte bByte) {        int iRet = bByte;        // System.out.println("iRet="+iRet);        if (iRet < 0) {            iRet += 256;        }        int iD1 = iRet / 16;        int iD2 = iRet % 16;        return strDigits[iD1] + strDigits[iD2];    }    // 返回形式只為數字    private static String byteToNum(byte bByte) {        int iRet = bByte;        System.out.println("iRet1=" + iRet);        if (iRet < 0) {            iRet += 256;        }        return String.valueOf(iRet);    }    // 轉換位元組數組為16進位字串    private static String byteToString(byte[] bByte) {        StringBuffer sBuffer = new StringBuffer();        for (int i = 0; i < bByte.length; i++) {            sBuffer.append(byteToArrayString(bByte[i]));        }        return sBuffer.toString();    }    public static String GetMD5Code(String strObj) {        String resultString = null;        try {            resultString = new String(strObj);            MessageDigest md = MessageDigest.getInstance("MD5");            // md.digest() 該函數傳回值為存放雜湊值結果的byte數組            resultString = byteToString(md.digest(strObj.getBytes()));        } catch (NoSuchAlgorithmException ex) {            ex.printStackTrace();        }        return resultString;    }    public static void main(String[] args) {        System.out.println(MD5.GetMD5Code("123456"));    }}