使用MD5进行加盐加密

首先引入一个jar包：

 <dependency>
      <groupId>commons-codec</groupId>
      <artifactId>commons-codec</artifactId>

  </dependency> 

public class MD5Utils {
/**
* 普通MD5
* 
* @author daniel
* @time 2016-6-11 下午8:00:28
* @param inStr
* @return
*/
public static String MD5(String input) {
MessageDigest md5 = null;
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
* 
* @author daniel
* @time 2016-6-11 下午8:45:04
* @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] = 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
* 
* @author daniel
* @time 2016-6-11 下午8:45:39
* @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 md5Hex(password + salt).equals(new String(cs1));
}


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

public static void main(String[] args) {


plaintext = "123456";
System.out.println("原始：" + plaintext);
System.out.println("普通MD5后：" + MD5Utils.MD5(plaintext));

// 获取加盐后的MD5值
String ciphertext = MD5Utils.generate(plaintext);
System.out.println("加盐后MD5：" + ciphertext);
System.out.println("是否是同一字符串:" + MD5Utils.verify(plaintext, ciphertext));
}