Learn Java for Web Development

258 CHAPTER 5: Building Java Web Applications with Spring Web MVC

import com.apress.bookstore.model.Book;

public class BookValidator implements Validator {

@Override

public boolean supports(Class clazz) {

return Book.class.equals(clazz);

}

@Override

public void validate(Object obj, Errors errors) {

Book book = (Book) obj;

ValidationUtils.rejectIfEmptyOrWhitespace(errors, "bookTitle", "field.required",
"Required Field");

if (! errors.hasFieldErrors("bookTitle")) {

if (book.getBookTitle().isEmpty())

errors.rejectValue("Title", "", "Cannot be left empty!");

}

 Lines 19 to 23: Typical validations in the application

The controller named AddBookController is updated for the validation, as shown in Listing 5-51.

Listing 5-51. Updating the AddBookController

package com.apress.bookstore.controller;

import java.util.List;

import org.springframework.beans.factory.annotation.Autowired;

import org.springframework.stereotype.Controller;

import org.springframework.ui.ModelMap;

import org.springframework.validation.BindingResult;

import org.springframework.web.bind.WebDataBinder;

import org.springframework.web.bind.annotation.InitBinder;

import org.springframework.web.bind.annotation.ModelAttribute;

import org.springframework.web.bind.annotation.RequestMapping;

import org.springframework.web.bind.annotation.RequestMethod;

import org.springframework.web.bind.support.SessionStatus;

import org.springframework.web.context.request.WebRequest;

import com.apress.bookstore.model.Author;

import com.apress.bookstore.model.Book;

import com.apress.bookstore.service.AuthorService;

import com.apress.bookstore.service.BookService;

import com.apress.bookstore.validator.BookValidator;