Java常用工具类——MD5

参考文档

md5

import org.apache.commons.codec.binary.Hex;

import java.nio.charset.Charset;
import java.security.MessageDigest;
import java.security.NoSuchAlgorithmException;
import java.util.Objects;
import java.util.Random;

/**
 * MD5工具类，加盐
 *
 * @author daniel
 * @email 576699909@qq.com
 * @time 2016-6-11 下午7:57:36
 */
public class Md5Util {

    /**
     * 普通MD5
     *
     * @param input
     * @return
     */
    public static String md5(String input) {
        MessageDigest md5;
        try {
            md5 = MessageDigest.getInstance("MD5");
        } catch (NoSuchAlgorithmException e) {
            return "check jdk";
        } catch (Exception e) {
            e.printStackTrace();
            return "";
        }
        char[] charArray = input.toCharArray();
        byte[] byteArray = new byte[charArray.length];

        for (int i = 0; i < charArray.length; i++) {
            byteArray[i] = (byte) charArray[i];
        }

        byte[] md5Bytes = md5.digest(byteArray);
        StringBuffer hexValue = new StringBuffer();
        for (int i = 0; i < md5Bytes.length; i++) {
            int val = ((int) md5Bytes[i]) & 0xff;
            if (val < 16) {
                hexValue.append("0");
            }
            hexValue.append(Integer.toHexString(val));
        }
        return hexValue.toString();
    }


    /**
     * 加盐MD5
     *
     * @param password
     * @return
     */
    public static String generate(String password) {
        Random r = new Random();
        StringBuilder sb = new StringBuilder(16);
        sb.append(r.nextInt(99999999)).append(r.nextInt(99999999));
        int len = sb.length();
        if (len < 16) {
            for (int i = 0; i < 16 - len; i++) {
                sb.append("0");
            }
        }
        String salt = sb.toString();
        password = md5Hex(password + salt);
        char[] cs = new char[48];
        for (int i = 0; i < 48; i += 3) {
            cs[i] = Objects.requireNonNull(password).charAt(i / 3 * 2);
            char c = salt.charAt(i / 3);
            cs[i + 1] = c;
            cs[i + 2] = password.charAt(i / 3 * 2 + 1);
        }
        return new String(cs);
    }

    /**
     * 校验加盐后是否和原文一致
     *
     * @param password
     * @param md5
     * @return
     */
    public static boolean verify(String password, String md5) {
        char[] cs1 = new char[32];
        char[] cs2 = new char[16];
        for (int i = 0; i < 48; i += 3) {
            cs1[i / 3 * 2] = md5.charAt(i);
            cs1[i / 3 * 2 + 1] = md5.charAt(i + 2);
            cs2[i / 3] = md5.charAt(i + 1);
        }
        String salt = new String(cs2);
        return Objects.equals(md5Hex(password + salt), new String(cs1));
    }

    /**
     * 获取十六进制字符串形式的MD5摘要
     *
     * @param src 十六进制字符串
     * @return
     */
    private static String md5Hex(String src) {
        try {
            MessageDigest md5 = MessageDigest.getInstance("MD5");
            byte[] bs = md5.digest(src.getBytes(Charset.forName("utf-8")));
            return new String(new Hex().encode(bs), Charset.forName("utf-8"));
        } catch (Exception e) {
            return null;
        }
    }


}