Username availability check using Servlet, AJAX and MySQL

Sometimes we need to check username availability instantly before a user presses the submit button after filling a long-sized signup form. In this case we can use AJAX with any technologies like PHP, Codeigniter, Servlet, Struts, JSF, Spring etc. for checking whether the input username is avaialable or already occupied by someone else. So if we give instant result to the user for username availability then sometimes it makes more sensible than while pressing the submit button and goes top of the signup form to rectify the username input field if input username is not available.

This tutorial shows how to check username availability using Servlet, AJAX and MySQL. So after finishing this example you will be able to apply the same logic to any Servlet based web framework or any server side technologies such as PHP, Codeigniter etc. Continue reading “Username availability check using Servlet, AJAX and MySQL”

Spring Data JPA Entity Graphs

One of the important features in JPA 2.1 is the ability to specify fetch plans using Entity Graphs. This is useful since it allows you to customize the data that is retrieved with a query or find operation. It is expected to display data from the same entity in different and several ways when working with mid to large size applications. In other cases, you just need to select a smallest set of information to optimize the performance of your application.

Typically you do not have many mechanisms to control what is loaded or what is not loaded in a JPA Entity. You could use EAGER/LAZY fetching, but these definitions are pretty much static. You are unable to change their behaviour at runtime when retrieving data, meaning that you are stuck with what was defined in the entity. Changing these amid development is a nightmare, since it can cause queries to behave unexpectedly. Another way to control loading is to write specific JPQL queries. Continue reading “Spring Data JPA Entity Graphs”

Call Stored Procedure using Spring StoredProcedure

This tutorial will show you how we can stored procedure using Spring SimpleJdbcCall. For this tutorial we will create a standalone maven project in Eclipse.

If you already have an idea on how to create a maven project in Eclipse will be great otherwise I will tell you here how to create a maven project in Eclipse.

Sometimes we need to call a stored procedure while a single SQL statement is unable to fulfil our requirements because, it permits to execute multiple SQL statements and it also allows us to execute these SQL statements in a transactional unit in an efficient manner to avoid any inconsistency sometimes occurs during the execution of multiple SQL statements. Continue reading “Call Stored Procedure using Spring StoredProcedure”

Call Stored Procedure using Spring SimpleJdbcCall

This tutorial will show you how we can stored procedure using Spring SimpleJdbcCall. For this tutorial we will create a standalone maven project in Eclipse.

If you already have an idea on how to create a maven project in Eclipse will be great otherwise I will tell you here how to create a maven project in Eclipse.

Sometimes we need to call a stored procedure while a single SQL statement is unable to fulfil our requirements because, it permits to execute multiple SQL statements and it also allows us to execute these SQL statements in a transactional unit in an efficient manner to avoid any inconsistency sometimes occurs during the execution of multiple SQL statements. Continue reading “Call Stored Procedure using Spring SimpleJdbcCall”