md加密 16位 32位

16位大写

//生成MD5
public static String getMD5(String message) {
String md5 = "";
try {
MessageDigest md = MessageDigest.getInstance("MD5"); // 创建一个md5算法对象
byte[] messageByte = message.getBytes("UTF-8");
byte[] md5Byte = md.digest(messageByte); // 获得MD5字节数组,16*8=128位
md5 = bytesToHex(md5Byte); // 转换为16进制字符串
} catch (Exception e) {
e.printStackTrace();
}
return md5;
}

// 二进制转十六进制
public static String bytesToHex(byte[] bytes) {
StringBuffer hexStr = new StringBuffer();
int num;
for (int i = 0; i < bytes.length; i++) {
num = bytes[i];
if(num < 0) {
num += 256;
}
if(num < 16){
hexStr.append("0");
}
hexStr.append(Integer.toHexString(num));
}
return hexStr.toString().toUpperCase();
}

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//32位小写

String sign = encryption(str);

public static String encryption(String plain) {
String re_md5 = new String();
MessageDigest md;
try {
md = MessageDigest.getInstance("MD5");
md.update(plain.getBytes());
byte b[] = md.digest();
int i;
StringBuffer buf = new StringBuffer("");
for (int offset = 0; offset < b.length; offset++) {
i = b[offset];
if (i < 0)
i += 256;
if (i < 16)
buf.append("0");
buf.append(Integer.toHexString(i));
}
re_md5 = buf.toString();
} catch (NoSuchAlgorithmException e) {
// TODO Auto-generated catch block
e.printStackTrace();
}
return re_md5;
}