Spring 5.0 Projects

Validation

A user sends the data in JSON format and it must be validated before entering into the system to avoid any backend errors. Instead of imposing a full list of validations, we will implement a few basic validations. For example, validating an existing username,the role list has invalid values other than ROLR_USER and ROLE_ADMIN. The code looks as follows:

if (userRegistrationDto.username != null) {    var existingUser : User? = userRepository?.findByUsername(                                            userRegistrationDto.username)     if (existingUser != null) {        errors.reject("Existing username","User is already exist with username                                         '${userRegistrationDto.username}'. ")    }}if( userRegistrationDto.roleList.isEmpty()){    errors.reject("No Roles provided","Please provide roles")}else ...