Java Hibernate ManyToMany Tutorial – With Add and Delete examples

The many-to-many mappings and usage thereof can be a little bit weird on first glance.

This tutorial demonstrates:

  1. The mappings (Annotations not XML).
  2. Adding an entity to a group.
  3. Removing an entity from a group.
  4. Listing parents with children.
  5. Listing children with parents.

image

(The Hibernate Logic is completely separate from the UI)

The project is available to download at the bottom of this post.

Continue reading “Java Hibernate ManyToMany Tutorial – With Add and Delete examples”

Spring 3 MVC – Adding Objects to a List element on the fly at form submit – (Generic method)

Edit 10-Feb-2015

A much better approach to this problem is simply to use JSON. A number of comments below are in regard to nested lists. The solution detailed here does not readily facilitate nested lists. The solution outlined in this blog does: http://outbottle.com/spring-4-web-mvc-json-handling/. JSON is the recommended way of achieving “Adding Objects to a List element on the fly”

End Edit

Edit 12-Feb-2015

Alternatively, this blog also demonstrates the solution:

Spring 4 Web MVC with AngularJS

Abstract

The project downloadable below is an answer to a question repeated in this blog (Spring 3 MVC – Adding Objects to a List element on the fly at form submit – (Generic method))

“How can I submit nested lists of objects?”

The answer is AJAX and JSON.

A very good approach to this is with AngularJS and Spring as demonstrated here.

End Edit

 

ok, hard to describe this one and hard to find stuff on google so here’s an image explaining.

Add and Remove Items from List Dynamically in Spring 3 Web MVC
Add and Remove Items from List Dynamically in Spring 3 Web MVC

When clicked, the ‘Add’ and ‘Remove’ links in the image generate JavaScript events which add and remove the HTML elements dynamically client-side. The idea is to allow a Java List Object to have elements added and removed dynamically on form submission.

A Generic JavaScript library is provided. It makes the process of dynamically adding List elements (rows or Person objects in this example) effortless for any situation. The JavaScript library provides callabacks thus facilitating an AJAX implementation with little effort.

The Netbeans project and the JavaScript file are available for download at the bottom of the page.

Continue reading “Spring 3 MVC – Adding Objects to a List element on the fly at form submit – (Generic method)”

Hello Spring 3 Security with Netbeans – Role Based Method Protection

This tutorial will outline in simple steps how to do the following:

  1. Create Spring 3 Web MVC project using Netbeans
  2. Introduce Spring Security measures
  3. Limit @Controller method invocation to certain User-Role’s using Annotations
  4. Roles and users are defined within XML configurations.
  5. The full source code is available for download here

Continue reading “Hello Spring 3 Security with Netbeans – Role Based Method Protection”

Custom Annotated Validation with Spring 3 Web MVC

My previous tutorial detailed using Hibernate Validation within Spring 3 Web MVC.  This tutorial shows how to create custom validation annotations.

E.g.

This example annotation only permits the word ‘John’. Optionally, it can be case-sensitive.  Continue reading “Custom Annotated Validation with Spring 3 Web MVC”

Spring 3 Web MVC – Exception Handling – incorporating AJAX

Spring 3 Web MVC Exception Handling with AJAX
Spring 3 Web MVC Exception Handling

This tutorial demonstrates how to handle exceptions in Spring 3 Web MCV.
Emphasis is given to Handling  exceptions that occur during AJAX requests. I.e. in the event of an exception during an AJAX request,  it is not desirable to redirect to an error page, instead JavaScript error handling code should be invoked with relevant information passed in.

 

A Netbeans project is available for download at the bottom of this page.

Continue reading “Spring 3 Web MVC – Exception Handling – incorporating AJAX”

Integrating Hibernate with Spring 3 Web MVC

This tutorial on “Integrating Hibernate with Spring 3 Web MVC” incorporates:

  1. Hibernate Transaction Control
  2. @RequestMapping friendly URL’s. More on this specific Spring 3 Web MVC friendly URL topic here. (Alternative @RequestParam method here)
  3. A Generic DAO suitable for Hibernate operations with Spring 3 Web MVC. More here in this separate Generic DAO tutorial.
  4. Spring 3 Web MVC Dependency Injection (DI) and Inversion  of Control (IoC). More on DI and IoC here.
  5. Netbeans (7.1.1 used here but any version will do)

The complete Netbeans project is available for download here. The SQL for the project is included in the download in the WEB-INF folder.

Update: Jan 8, 2014

———–

The project originally available for download does not work with Netbeans 8 due to libraries that were in Netbeans 7.1.1 no longer available in Netbeans 8. Additionally, a comment below referencing Netbeans 7.0 .1 may suggest the same problem. This enforces the point that a dependency management utility is a much better means of building projects. To that end this project has been recreated using Maven. This ensures it will work irrespective of IDE version. In fact because it’s a maven project it’s not dependant on an IDE at all. It should work on any IDE that supports Maven. Netbeans of course, does support Maven. Here is the download link SpringHibernateCrudMvn for the Maven version of this application.

The POM is quite comprehensive in that it includes support for Spring, Spring-Security, Jackson, Hibernate, Hibernate-search and a bunch of other utilities. It can serve as a template to a certain extent.

—————————————————— (/End Update)

Continue reading “Integrating Hibernate with Spring 3 Web MVC”

Setting the Welcome Page in Spring Web MVC

In any Spring Web MVC application, there is a need to set the default landing or welcome page.

Traditionally in Java web applications, this is done in the web.xml file as so:

Or in a spring web mvc application, it might be like this:

With a corresponding controller class RequestMapping:

 

This is ok, because “/” is a valid existing URL but, if the required welcome page is to be a virtual URL such as /person/list a little more creativity is required.
Continue reading “Setting the Welcome Page in Spring Web MVC”

Determining the primary key property name using Hibernate

Simple method:

String idPropertyName = sessionFactory.getClassMetadata(User.class).getIdentifierPropertyName();

To get the actual value see this tutorial

Elaboration
Continue reading “Determining the primary key property name using Hibernate”

Annotated Dependency Injection / Inversion of Control (DI / IoC) in Spring 3 Web MVC using Netbeans

This tutorial will detail how to insert services and components (Dependency Injection) into a Spring 3 Web MVC Netbeans application.

The process used is Dependency Injection (DI) or Inverse of Control (IoC) whereby Spring will instantiate (or inject) certain components at runtime rather than at having them initiated at compile time.  This provides a highly decoupled design which facilitates ‘change’ more easily. Importantly, it also makes comprehensive Unit Testing (with Mock Objects) much easier to achieve. IoC is a conventional design pattern.

This tutorial is quite comprehensive in that it will simulate CRUD operations on ‘Person’ objects. For simplicity, it does not used a database, data will be put stored in the ‘HttpSession’ object instead.

The code is available for download at the bottom of this page. Continue reading “Annotated Dependency Injection / Inversion of Control (DI / IoC) in Spring 3 Web MVC using Netbeans”

Spring 3 Web MVC – Friendly URL using RequestMapping variable URI

Following on from a previous tutorial on getting a hello world Spring 3 Web MVC application running in Netbeans here, this tutorial will explain how to achieve friendly URL’s incorporating variables.

E.g.

http://localhost:8084/HelloSpring/person?name=John

becomes

http://localhost:8084/HelloSpring/person/John
Continue reading “Spring 3 Web MVC – Friendly URL using RequestMapping variable URI”