Validating input in java
Similar to the previous tutorial, our model will eventually look like this: package be.g00glen00b.controller; import *; import org.springframework.beans.factory.annotation. Idea Repository; @Rest Controller @Request Mapping("/api/ideas") public class Idea Controller This example looks fine except that there’s one problem… You can easily add ideas that have no title (which should be required) or you can enter a title/description that has any length, eventually surpassing the database limits resulting in unexpected exceptions/behavior.
To report errors, it is necessary to provide an Error Handler to the underlying implementation.
Imperative validation allows users to do this by Firing the validation from the Bean method In this type of validation we write a method in the bean to validate the UIComponents and invoke this method from the jsf page through a validator attribute in the input Text tag.
Now lets see consider an example of firing a validation from the Bean.package com.bean; import
This means the validation engine directly accesses the instance variable and does not invoke the property accessor method even if such an accessor exists.
Constraints can be applied to fields of any access type (public, private etc.).