Codeimport java.security.MessageDigest; public class MD5 { //十六进制下数字到字符的映射数组 private final static String[] hexDigits = { "0", "1", "2", "3", "4", "5", "6", "7", "8", "9", "a", "b", "c", "d", "e", "f" }; /** 把inputString加密 */ public static String createPassword(String inputString) { return encodeByMD5(inputString); } /** * * Creation Date:2008-3-14 * TODO 验证输入的密码是否正确 * @param password 加密后的源密码 * @param inputString 输入字符串 * @return boolean true为真,false为假 * @Author tianw */ public static boolean authenticatePassword(String password, String inputString) { if (password.equals(encodeByMD5(inputString))) { return true; } else { return false; } } /** 对字符串进行MD5加密 */ private static String encodeByMD5(String originString) { if (originString != null) { try { // 创建具有指定算法名称的信息摘要 MessageDigest md = MessageDigest.getInstance("MD5"); // 使用指定的字节数组对摘要进行最后更新,然后完成摘要计算 byte[] results = md.digest(originString.getBytes()); // 将得到的字节数组变成字符串返回 String resultString = byteArrayToHexString(results); return resultString.toUpperCase(); } catch (Exception ex) { ex.printStackTrace(); } } return null; } /** * * Creation Date:2008-3-14 * TODO 转换字节数组为十六进制字符串 * @param b 字节数组 * @return String 十六进制字符串 * @Author tianw */ private static String byteArrayToHexString(byte[] b) { StringBuffer resultSb = new StringBuffer(); for (int i = 0; i < b.length; i++) { String ss = byteToHexString(b[i]); resultSb.append(ss); } return resultSb.toString(); } /** 将一个字节转化成十六进制形式的字符串 */ private static String byteToHexString(byte b) { int n = b; if (n < 0) n = 256 + n; int d1 = n / 16; int d2 = n % 16; return hexDigits[d1] + hexDigits[d2]; } public static void main(String[] args) { System.out.println(MD5.createPassword("123456")); } }