Preface

There are a lot of books written about Spring Framework and its subprojects. A multitude of online references are also available. Most of these massive resources discuss Spring in a lot of detail, which makes learning Spring a very time-consuming and sometimes tedious effort. The idea of this book is to allow novice Java developers or architects to master Spring without spending much time and effort and at the same time provide them with a strong foundation on the topic in order to enable them to design high-performance systems that are scalable and easily maintainable.

We have been using Spring Framework and its subprojects for more than a decade to develop enterprise applications in various domains. While the usage of Spring quickly raises the design quality of projects with its smart templates and subframeworks abstracting many error-prone and routine programming tasks, a developer needs a thorough understanding of its concepts, features, best practices, and above all, the Spring programming model in order to utilize Spring to its best.

We have seen Spring used wrongly inside many projects mainly because the developer either didn't understand the right use of a particular Spring component or didn't bother to follow the design approach Spring suggests for that component. Often, developers didn't appear to have the right knowledge of Spring Framework; when asked, their complaint mostly was the uphill task of learning such a vast framework from huge documentation. Most of this category of developers find Spring a mammoth framework that is difficult to learn, which is not really true.

Spring, if the basics are understood correctly, is very easy to conquer further. A developer needs to understand the Spring style of programming and architecting applications, and the result will be a piece of art. The design will look simple, pretty straightforward, and easily understandable, which is very important for the evolution of applications in the long run. This book is an attempt to fill that gap and provide a very solid foundation in Spring, its concepts, design styles, and best practices, in a very quick and easy way.

This book tries to engage the reader by providing the feeling of developing a realistic, modern enterprise application using Spring and its necessary features while giving him or her a solid understanding of its concepts, benefits, and usage with real-life examples. It covers the most important concepts and features of Spring Framework and a few of its critical subprojects that are necessary for building modern web applications.

The goal of Spring is to simplify enterprise application development. We hope this book simplifies mastering Spring so that developers can build smarter systems that make the world a better place.

What this book covers

Chapter 1, Getting Started with Spring Core, introduces the core Spring Framework, including its core concepts, such as POJO-based programming, Dependency Injection, and Aspect Oriented Programming, to the reader. It further explains the Spring IoC container, bean configurations, Spring Expression Language (SpEL), resource management, and bean definition profiles, all which become the foundation for the advanced topics.

Chapter 2, Building the Web Layer with Spring Web MVC, gives in-depth coverage of the Spring MVC web framework with its features and various different ways of configuring and tuning web applications using Spring. The chapter covers the building of both view-based web applications and REST APIs with many available options, including asynchronous request processing.

Chapter 3, Accessing Data with Spring, discusses the different data-access and persistence mechanisms that Spring offers, including the Spring Data family of projects, such as Spring Data JPA and Spring Data Mongo. This chapter enables the reader to design an elegant data layer for his or her Spring application, delegating all the heavylifting to Spring.

Chapter 4, Understanding WebSocket, discusses the WebSocket technology, which is gaining wider usage inside modern web applications, where low latency and high frequency of communication are critical. This chapter explains how to create a WebSocket application and broadcast a message to all subscribed clients as well as send a message to a specific client, and shows how a broker-based messaging system works with STOMP over WebSocket. It also shows how Spring's WebSocket fallback option can tackle browser incompatibility.

Chapter 5, Securing Your Applications, teaches the reader how to secure his or her Spring applications. It starts with authentication and explains Spring flexibility on authorization. You learn how to integrate your existing authentication framework with Spring. On authorization, it shows how to use Spring EL expressions for web, method, and domain object authorization. It also explains the OAuth 2.0 Authorization Framework and how to allow third-party limited access to user's protected resources on a server without sharing user's username and password.

Chapter 6, Building a Single-Page Spring Application, demonstrates how Spring can be used as the API server for modern single-page applications (SPAs) with an example of an Ember JS application. At first, it introduces the concept of SPAs, and then it explores using Ember JS to build the SPA. Finally, it covers building the backend API that processes requests asynchronously using Spring MVC and implements persistence using Spring Data JPA.

Chapter 7, Integrating with Other Web Frameworks, demonstrates how Spring can be integrated with Java web frameworks such as JSF and Struts so that even web applications not based on Spring MVC can leverage the power of Spring.

What you need for this book

In order to execute the sample projects used in this book, you need the following software installed on your computer:

For all chapters, in general, you need the following software:

• Java version 8 onwards
• Spring Framework 4.x
• Apache Maven 3.x.x
• Apache Tomcat 8.x

For Chapter 3, Accessing Data with Spring, you need the following databases:

• PostgreSQL 8 onwards
• MongoDB 3.x

Additionally, for Chapter 6, Building a Single-Page Spring Application, you need the following software:

• Node.js version 4.x
• Bower JS in the latest version

Who this book is for

If you are a Java developer who is looking to master enterprise Java development using Spring Framework, then this book is ideal for you. A prior understanding of core Java programming and a high-level understanding of Spring Framework is recommended. Having sound knowledge of Servlet-based web development in Java and basic database concepts would be an advantage but not a requirement.

Conventions

In this book, you will find a number of text styles that distinguish between different kinds of information. Here are some examples of these styles and an explanation of their meaning.

Code words in text, database table names, folder names, filenames, file extensions, pathnames, dummy URLs, user input, and Twitter handles are shown as follows: "Spring provides mock classes for both client and server sides inside the org.springframework.mock.http and org.springframework.mock.http.client packages."

A block of code is set as follows:

<dependencies>
  <dependency>
    <groupId>org.springframework</groupId>
    <artifactId>spring-context</artifactId>
    <version>${spring-framework.version}</version>
  </dependency>
  ...
</dependencies>

Any command-line input or output is written as follows:

mvn clean package spring-boot:run -Dserver.contextPath=/myapp -Dserver.port=9090

New terms and important words are shown in bold. Words that you see on the screen, for example, in menus or dialog boxes, appear in the text like this: "STS and Eclipse allow you to run Java web apps from the IDE just by right-clicking Run As and then Run on Server."

Note

Warnings or important notes appear in a box like this.

Tip

Tips and tricks appear like this.

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