validate input in Thymeleaf

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[愿得一人]
[愿得一人] 2021-01-07 09:20

I have this input:

Masa: 
    
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2条回答
  • 2021-01-07 09:49

    It seems like you want to implement server side validation. For this the best approach is to use validators and its bindingResult. Steps to implement server side validation is

    1. Have for model

      public class PersonForm {
        private String name;
      
       public String getName() {
          return this.name;
      }
      
       public void setName(String name) {
          this.name = name;
      }
      }
      
    2. Use form model in html

      <form action="#" th:action="@{/personForm}" th:object="${personForm}" method="post">
      <table>
          <tr>
              <td><label th:text="#{label.name}+' :'"></label></td>
              <td><input type="text" th:field="*{name}" /></td>
              <td th:if="${#fields.hasErrors('name')}" th:errors="*{name}">Generic Error</td>
          </tr>
          <tr>
              <td><button type="submit">Submit</button></td>
          </tr>
      </table>
      </form>
      
      1. Have validator class

      @Component

      public class PersonFormValidator implements Validator {
      @Override
      public boolean supports(Class<?> clazz) {
          return PersonForm.class.equals(clazz);
      }
      
      @Override
      public void validate(Object target, Errors errors) {
          ValidationUtils.rejectIfEmpty(errors, "name", "field.name.empty");
          PersonForm p = (PersonForm) target;
      
          if (p.getName().equalsIgnoreCase("XXX")) {
              errors.rejectValue("name", "Name cannot be XXX");
          }
      }}
      
      1. Bind validator to controller and let spring do the magic.

      @Controller

      public class WebController {
      @Autowired
      PersonFormValidator personFormValidator;
      
      
      @InitBinder("personForm")
      protected void initPersonFormBinder(WebDataBinder binder) {
      binder.addValidators(personFormValidator);
      }
      
      @PostMapping("/personForm")
      public String checkPersonInfo(@Validated PersonForm personForm, BindingResult bindingResult, final RedirectAttributes redirectAttributes) {
      if (bindingResult.hasErrors()) {
          return "personForm";
      }
      redirectAttributes.addFlashAttribute("personResult",  apiClientService.getPersonResult(personForm));
      return "redirect:/spouseForm";
      }
      }
      
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  • 2021-01-07 09:51
    @PostMapping("/cal-bmi")
    public String calculateBmiForm(Model model, Integer masa, Integer wzrost) {
    
    String x = String.valueOf(masa);
        String y = String.valueOf(wzrost);
    
    
        if(x==null ){
        model.addAttribute("wzrost",true);
        return"views/success";
    }
        if(y==null ){
            model.addAttribute("wzrost",true);
            return"views/success";
        }
    }
    

    ANd when i get a valu form masa and wzrost i check from null, i click submit alwas nullpointerexception

     <form th:action="@{/cal-bmi}" method="post">
    
        <ul class="gender-options">
            <input id="man" type="radio" name="gender" value="male" required  />
            <label for="man">mężczyzna</label> &frasl;
            <input id="woman" type="radio" name="gender" value="female"/>
            <label for="woman">kobieta</label>
        </ul>
    
    
        Masa: <input type="number" class="form-control form-text" required placeholder="(kg)" name="masa"/>
    
        <!--<div class="text col-sm-12 error" th:if="${wzrost}">-->
            <!--<p class="text text-center">-->
                <!--To pole jest wymagane-->
            <!--</p>-->
        <!--</div>-->
        Wzrost: <input type="number" class="form-control form-text " required placeholder="(cm)" name="wzrost"/>
    
        <!--<div class="text col-sm-12 error" th:if="${wzrost}">-->
            <!--<p class="text text-center">-->
                <!--To pole jest wymagane-->
            <!--</p>-->
        <!--</div>-->
        <input type="submit" class="col-lg-10 btn btn-primary" value="Oblicz"/>
    </form>
    

    Now i used required but is not good solution

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