CODEWITHSUNDEEP
ajaxangularjsvalidationspring-mvcknockout.js
Tunguska
Tunguska

Reputation: 1205

Server side validation with Spring MVC and Knockout JS

Qustion:

I am looking for a good solution to validate my data in Spring MVC controller and populate the errors with Knockout JS. I imagine something similiar to the existing <form:errors path=""> from Spring Tags. The solution should provide following properties:

  1. Form submission with jQuery and AJAX
  2. Server side validation with @ModelAttribute and @Valid
  3. Error messages should be automatically populated to some "Knockout Error Tags"

Does something similar already exist? I am also open to switch to another JS Framework if this would provide the needed functionalities. (Angular, Backbone etc.)

My custom solution:

I store all errors in a Map<String, String> where the key is the field name and the value is the error message and populated the errors in Knockout. The problem with this solution is, that KnockoutJS looses all unbinded fields after validation.

Validate: 

helper.getErrors().put("firstName", messageSourceProvider.getMessage("validation.requiredDefault"));

Serialize:

JSONSerializer serializer = new JSONSerializer();
serializer.include("helper");
serializer.include("helper.errors");
String json = serializer.serialize(helper);

Knockout:

<!-- ko foreach: errors -->
    <!-- ko if: key === 'firstName' -->
        <span data-bind='text: value' class="spring-error ordinary-tooltip fa fa-lg fa-exclamation-circle"></span> 
    <!-- /ko -->
<!-- /ko -->

Upvotes: 5

Views: 580

Answers (1)

Tyler Smith
Tyler Smith

Reputation: 528

The method I've undertaken to handle your problem is to fire off an ajax call prior to allowing the form to submit. If there are validation issues or errors I stop the form from submitting and display the errors. This way the bindings are still intact and after the user fixes the issues the form data can be resubmitted again.

Upvotes: 0

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