java 40 lines · 8 steps

Building a Spring MVC form controller

A Spring MVC controller that renders an employee form, shares reference data, validates input, and redirects after saving.

Explained by highlit

Spring Intermediate mvc form-handling validation dependency-injection post-redirect-get

1@Controller
2@RequestMapping("/employees")
3public class EmployeeController {
4 
  private final DepartmentRepository departmentRepository;
  private final EmployeeService employeeService;
7 
  public EmployeeController(DepartmentRepository departmentRepository, EmployeeService employeeService) {
      this.departmentRepository = departmentRepository;
      this.employeeService = employeeService;
  }
12 
  @ModelAttribute("departments")
  public List<Department> populateDepartments() {
      return departmentRepository.findAllByActiveTrueOrderByName();
  }
17 
  @ModelAttribute("employmentTypes")
  public EmploymentType[] populateEmploymentTypes() {
      return EmploymentType.values();
  }
22 
  @GetMapping("/new")
  public String newEmployeeForm(Model model) {
      model.addAttribute("employee", new EmployeeForm());
      return "employees/form";
  }
28 
  @PostMapping
  public String create(@Valid @ModelAttribute("employee") EmployeeForm form,
                       BindingResult bindingResult,
                       RedirectAttributes redirectAttributes) {
      if (bindingResult.hasErrors()) {
          return "employees/form";
      }
      Employee saved = employeeService.register(form);
      redirectAttributes.addFlashAttribute("message", "Employee " + saved.getName() + " created");
      return "redirect:/employees/" + saved.getId();
  }
40}

01 / 01

STEP 01

Walkthrough

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Three takeaways

1@ModelAttribute methods centralize reference data so every view under the controller has it without repeating lookups.
2Pairing @Valid with BindingResult lets you re-render the form on failure instead of throwing.
3The Post-Redirect-Get pattern with flash attributes prevents duplicate submissions and survives the redirect.

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