Introducing Spring Framework

Chapter 1 ■ Your First Spring Application
Then, in your main method, you are calling the Spring container by using the ApplicationContext class. This
class, with help from the other annotations (@Config, @ComponentScan, and @Bean), will create the container and wire
everything up for ready to use, so when you call the context.getBean method the Spring Container already knows
what object to use.
Note that if you change your implementation, it will be the only class to change; the other classes will remain
intact. This will create an extensible and robust application, even if it is as simple as the Hello World example.
■ ■Note If you need to get more information about dependency injection and how it is used with the Spring Framework,
I recommend the Pro Spring series of books from Apress.
In the following chapters, you will get more details on all of the features of the Spring Framework, the Spring
Extensions, and subprojects, plus how you can use them.
Spring Boot: Even Easier
With the release of the Spring Framework 4, the Spring team also released a new extension of the Spring technology:
Spring Boot. You are going to do a small example (the famous “Hello World”) using this new technology and yes, this
is also Spring.
Spring Boot makes development even easier. Any Spring application can be reduced to less code with minimum
effort, and it will be production-ready. Let’s create the folder structure and add the following files:
• build.gradle
••• src
••• main
••• java
••• com
••• apress
••• isf
••• spring
• HelloWorldController.java
This shows the structure you are going to use and the HelloWorldController.java file that it will run. Note that
it is necessary to create your build.gradle file to run your example (see Listing 1-5).
Listing 1-5. build.gradle
apply plugin: 'application'
mainClassName = System.getProperty("mainClass")
dependencies {
compile("org.springframework.boot:spring-boot-starter-web:1.0.2.RELEASE")
}
repositories {
mavenCentral()
maven {
8