week 11 作业

Boolean checkPw(String id, String password, String encPassword){
  if(encPassword==null){return false;}
  return encPassword.equals(MD5.encrypt(id+password));
}
    
public class MD5 {
  public static String encrypt(String data) {
		if (data == null || data.length() == 0) {
			return null;
		}
	  try {
      StringBuilder result = new StringBuilder();
      MessageDigest md = MessageDigest.getInstance("MD5");
      byte[] bytes = md.digest(data.getBytes(UTF_8));
      for (byte b :bytes) {
        String hex = Integer.toHexString(b&0xFF);
        if (hex.length() == 1)
          result.append("0");
        result.append(hex);
      }
      return result.toString();
    } catch (Exception e) {
      return null;
    }
  }
}