What is the use of BindingResult interface in spring MVC

Question

Is BindingResult useful to bind just exceptions with view  or something else   what is the exact use of BindingResult   Or is it useful in binding model attribute with view

User · Answer

Basically BindingResult is an interface which dictates how the object that stores the result of validation should store and retrieve the result of the validation errors  attempt to bind to disallowed fields etc   From Spring MVC Form Validation with Annotations Tutorial       BindingResult  is Spring   s object that holds the result of the   validation and binding and contains errors that may have occurred  The   BindingResult must come right after the model object that is validated   or else Spring will fail to validate the object and throw an   exception       When Spring sees  Valid  it tries to find the validator for the   object being validated  Spring automatically picks up validation   annotations if you have    annotation-driven    enabled  Spring then   invokes the validator and puts any errors in the BindingResult and   adds the BindingResult to the view model

User · Answer

It s important to note that the order of parameters is actually important to spring  The BindingResult needs to come right after the Form that is being validated  Likewise  the  optional  Model parameter needs to come after the BindingResult  Example    Valid     RequestMapping value     entry updateQuantity   method   RequestMethod POST  public String updateEntryQuantity  Valid final UpdateQuantityForm form                                    final BindingResult bindingResult                                     RequestParam  pk   final long pk                                    final Model model        Not Valid    RequestMapping value     entry updateQuantity   method   RequestMethod POST  public String updateEntryQuantity  Valid final UpdateQuantityForm form                                     RequestParam  pk   final long pk                                    final BindingResult bindingResult                                    final Model model

User · Answer

From the official Spring documentation         General interface that represents binding results  Extends the   interface for error registration capabilities  allowing for a   Validator to be applied  and adds binding-specific analysis and model   building       Serves as result holder for a DataBinder  obtained via the   DataBinder getBindingResult   method  BindingResult implementations   can also be used directly  for example to invoke a Validator on it    e g  as part of a unit test

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Particular example  use a BindingResult object as an argument for a validate method of a Validator inside a Controller   Then  you can check this object looking for validation errors    validator validate modelObject  bindingResult     if  bindingResult hasErrors               do something

User · Answer

BindingResult is used for validation    Example -   public  ResponseBody String nutzer  ModelAttribute value  nutzer   Nutzer nutzer  BindingResult ergebnis           String ergebnisText          if  ergebnis hasErrors                 nutzerList add nutzer               ergebnisText    Anzahl      nutzerList size             else              ergebnisText    Error                                return ergebnisText

User · Answer

Well its a sequential process  The Request first treat by FrontController and then moves towards our own customize controller with  Controller annotation   but our controller method is binding bean using modelattribute and we are also performing few validations on bean values   so instead of moving the request to our controller class  FrontController moves it towards one interceptor which creates the temp object of our bean and the validate the values  if validation successful then bind the temp obj values with our actual bean which is stored in  ModelAttribute otherwise if validation fails it does not bind and moves the resp towards error page or wherever u want

[spring-mvc] What is the use of BindingResult interface in spring MVC?

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