我正在使用以下代码块来生成MD5哈希值：
public static String encode(String data) throws Exception {
/* Check the validity of data */
if (data == null || data.isEmpty()) {
throw new IllegalArgumentException("Null value provided for "
+ "MD5 Encoding");
}
/* Get the instances for a given digest scheme MD5 or SHA */
MessageDigest m = MessageDigest.getInstance("MD5");
/* Generate the digest. Pass in the text as bytes,length to the
* bytes(offset) to be hashed; for full string pass 0 to text.length()
*/
m.update(data.getBytes(),data.length());
/* Get the String representation of hash bytes,create a big integer
* out of bytes then convert it into hex value (16 as input to
* toString method)
*/
String digest = new BigInteger(1,m.digest()).toString(16);
return digest;
}
当我使用String数据运行上述代码段[12,B006GQIIEM,MH-ANT2000]时,输出是一个31个字符的散列 – 268d43a823933c9dafaa4ac0e756d6a.
解决方法
您的代码中唯一的问题是当
MSB小于Ox10时,结果散列字符串将只有31个字节,而不是32个字节,缺少前导零.
以这种方式创建你的md5字符串：
byte messageDigest[] = m.digest();
hexString = new StringBuffer();
for (int i=0;i<messageDigest.length;i++) {
String hex=Integer.toHexString(0xFF & messageDigest[i]);
if(hex.length()==1)
hexString.append('0');
hexString.append(hex);
}
