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package mobvista.dmp.util;
import java.math.BigInteger;
import java.security.MessageDigest;
import java.security.NoSuchAlgorithmException;
import java.util.UUID;
/**
* @package: mobvista.dmp.util
* @author: wangjf
* @date: 2019-11-22
* @time: 11:48
* @email: jinfeng.wang@mobvista.com
* @phone: 152-1062-7698
*/
public class MD5Util {
// 如果前几位为0，则会删除0，出现少一两位。不足
public static String getMD5(String str) throws Exception {
try {
// 生成一个MD5加密计算摘要
MessageDigest md = MessageDigest.getInstance("MD5");
// 计算md5函数
md.update(str.getBytes());
// digest()最后确定返回md5 hash值，返回值为8为字符串。因为md5 hash值是16位的hex值，实际上就是8位的字符
// BigInteger函数则将8位的字符串转换成16位hex值，用字符串来表示；得到字符串形式的hash值
return new BigInteger(1, md.digest()).toString(16);
} catch (Exception e) {
throw new Exception("MD5加密出现错误，" + e.toString());
}
}
public static String getMD5Str(String plainText) {
try {
MessageDigest md = MessageDigest.getInstance("MD5");
md.update(plainText.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));
}
// 32位加密
return buf.toString();
// 16位的加密
// return buf.toString().substring(8, 24);
} catch (NoSuchAlgorithmException e) {
e.printStackTrace();
return "";
}
}
public static void main(String[] args) throws Exception {
UUID uid = UUID.randomUUID();
String str = getMD5Str(uid.toString());
System.out.println(uid.toString());
System.out.println(str);
// MySQLUtil.update("dwh", "ods_user_info", "20191130");
}
}