Java MD5加密算法工具类

package util;

import java.security.MessageDigest;
import java.security.NoSuchAlgorithmException;

public class MD5 {
    public static String encrypt(String s) {
        StringBuffer buf = new StringBuffer();
        try {
            MessageDigest md5 = MessageDigest.getInstance("MD5");
            md5.update(s.getBytes());
            byte[] bytes = md5.digest();

            for (int i = 0; i < bytes.length; i++) {
                int num = bytes[i];
                if (num < 0) {
                    num += 256;
                }

                // 如果小于16，则加0补齐16进制两位数
                if (num < 16) {
                    buf.append(0);
                }
                buf.append(Integer.toHexString(num));
            }
        } catch (NoSuchAlgorithmException e) {
            e.printStackTrace();
        }
        return buf.toString();
    }

    public static void main(String[] args) {
        String password = "HELLOhi";
        System.out.println(encrypt(password));
    }

}