Spring boot validation doesn't work

Question

I have Spring boot application and I can't show error message to user. Object without that data is not saved in the database and that is OK. But showing error message is the problem. When I debug i get errors size = 0

This is my model:

 @Size(min = 1, message = "Address is invalid.")
 @NotNull
 @Column
 private String address;

Controller

  @RequestMapping(value = "/create", method = RequestMethod.POST, 
  consumes = MediaType.APPLICATION_FORM_URLENCODED_VALUE)
  public String createNewBusiness(@Valid @ModelAttribute("business") 
  Business business, BindingResult result, Model model) {
  model.addAttribute("userEmail", getUserEmail());
   logger.info("/business/create:" + business.toString());
  LocationResponse locationResponse = geoService.getCoords(business.getAddress());

if(locationResponse.getStatus().equals("OK")) {
    business.setLatitude(locationResponse.getResults().get(0).getGeometry().getLocation().getLat());
    business.setLongitude(locationResponse.getResults().get(0).getGeometry().getLocation().getLng());
    business.setUserId(getUserId());

    businessService.createNew(business);

    model.addAttribute("business", business);

}else{
    business.setAddress(null);
    model.addAttribute("business", business);

}

if(result.hasErrors()){
    List<FieldError> errors = result.getFieldErrors();
    for (FieldError error : errors ) {
        System.out.println (error.getObjectName() + " - " + error.getDefaultMessage());
    }
    return "newBusiness";
}

return "business";

}

And Thymeleaf

<div class="input-field left m-0 w-100">
                        <i class="fa fa-map-marker prefix grey-text" aria-hidden="true"></i>
                        <input placeholder="Address" id="inputAddress" name="address" type="text" class="validate my-0" th:required="true">
                        <label th:errors="*{address}" th:if="${#fields.hasErrors('address')}" >Invalid address </label>
                    </div>

Answer 1

You need to use @Valid and on some also @ModelAttribute for the parameter of createNewBusiness() - depending on your parameters and stuff.

Also you need to add th:field="*{adress}" to your inputfield because it´s the ID of this inputfield in the framework.

---

So in you case the method header will look like this:

public String createNewBusiness(@ModelAttribute Business business,
    @Valid Model model, BindingResult result) {
    // ...
}

Answer 2

If you want to throw a custom validation error (for example, if you're validating a field by something other than the annotation validators in your model), you can do that through BindingResult#rejectValue() method. For example:

if (business.getEmail()  == null || business.getEmail().length() == 0) {
    result.rejectValue("email", "email.missing", "Must enter email");
}

Obviously email field is just an example, as you would need that email field on your thymeleaf resource as well as the error field.

More on this topic at https://docs.spring.io/autorepo/docs/spring-framework/3.2.8.RELEASE/javadoc-api/org/springframework/validation/Errors.html#rejectValue(java.lang.String,%20java.lang.String,%20java.lang.Object[],%20java.lang.String)