Spring: Developing Java Applications for the Enterprise

Chapter 8. Validate Your Products with a Validator

One of the most commonly expected behaviors of any web application is that it should validate user data. Every time a user submits data into our web application, it needs to be validated. This is to prevent security attacks, wrong data, or simple user errors. We don't have control over what the user may type while submitting data into our web application. For example, they may type some text instead of a date, they may forget to fill a mandatory field, or suppose we used 12-character lengths for a field in the database and the user entered 15-character length data, then the data cannot be saved in the database. Similarly, there are lots of ways a user can feed incorrect data into our web application. ...