Custom validator example

package com.howtodoinjava.demo.validator;
 
import org.springframework.stereotype.Component;
import org.springframework.validation.Errors;
import org.springframework.validation.ValidationUtils;
import org.springframework.validation.Validator;
 
import com.howtodoinjava.demo.model.EmployeeVO;
 
@Component
public class EmployeeValidator implements Validator 
{
 
    public boolean supports(Class clazz) {
        return EmployeeVO.class.isAssignableFrom(clazz);
    }
 
    public void validate(Object target, Errors errors) 
    {
        ValidationUtils.rejectIfEmptyOrWhitespace(errors, "firstName", "error.firstName", "First name is required.");
        ValidationUtils.rejectIfEmptyOrWhitespace(errors, "lastName", "error.lastName", "Last name is required.");
        ValidationUtils.rejectIfEmptyOrWhitespace(errors, "email", "error.email", "Email is required.");
    }
 
}

@RequestMapping(method = RequestMethod.POST)
public String submitForm(@ModelAttribute("employee") EmployeeVO employeeVO,
                        BindingResult result, SessionStatus status) 
{
     
    //Validation code
    validator.validate(employeeVO, result);
     
    //Check validation errors
    if (result.hasErrors()) {
        return "addEmployee";
    }
     
    //Store the employee information in database
    //manager.createNewRecord(employeeVO);
     
    //Mark Session Complete
    status.setComplete();
    return "redirect:addNew/success";
}

package com.howtodoinjava.demo.controller;
 
import org.springframework.beans.factory.annotation.Autowired;
import org.springframework.stereotype.Controller;
import org.springframework.ui.Model;
import org.springframework.validation.BindingResult;
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.annotation.SessionAttributes;
import org.springframework.web.bind.support.SessionStatus;
 
import com.howtodoinjava.demo.model.EmployeeVO;
import com.howtodoinjava.demo.service.EmployeeManager;
import com.howtodoinjava.demo.validator.EmployeeValidator;
 
@Controller
@RequestMapping("/employee-module/addNew")
@SessionAttributes("employee")
public class EmployeeController 
{
    @Autowired
    EmployeeManager manager;
     
    @Autowired
    EmployeeValidator validator;
     
    @RequestMapping(method = RequestMethod.GET)
    public String setupForm(Model model) 
    {
         EmployeeVO employeeVO = new EmployeeVO();
         model.addAttribute("employee", employeeVO);
         return "addEmployee";
    }
     
    @RequestMapping(method = RequestMethod.POST)
    public String submitForm(@ModelAttribute("employee") EmployeeVO employeeVO,
                            BindingResult result, SessionStatus status) 
    {
         
        validator.validate(employeeVO, result);
         
        if (result.hasErrors()) {
            return "addEmployee";
        }
        //Store the employee information in database
        //manager.createNewRecord(employeeVO);
         
        //Mark Session Complete
        status.setComplete();
        return "redirect:addNew/success";
    }
     
    @RequestMapping(value = "/success", method = RequestMethod.GET)
    public String success(Model model) 
    {
         return "addSuccess";
    }
}