Spring Boot: Fast MVC start
I planned to write an article about Spring Boot more than a year ago. Finally I have time and inspiration for this. So prepare yourself for 10 – 15 minutes of step by step tutorial. I’m going to demonstrate Spring Boot basics with Gradle and embedded Tomcat. I use Intellij IDEA instead of Eclipse but this shouldn’t be a problem for those of you who used to Eclipse.
Introduction to Spring Boot
What’s my goal? I want to develop something very similar to one of my previous tutorials about Spring with java configurations. It’s a good exercise to compare two different approaches for Spring development.
No doubt, most of you know what is the main aim of the Spring Boot. For the rest of readers I want to say that the Spring Boot makes developers happier because it takes care of configurations meanwhile a developer can focus on a code production. For more details read official reference.
Gradle build file
For managing dependencies and build of the project I use Gradle. Here is how build.gradle file looks:
01 02 03 04 05 06 07 08 09 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 | buildscript { repositories { //Required repos mavenCentral() } dependencies { //Required dependency for spring-boot plugin classpath 'org.springframework.boot:spring-boot-gradle-plugin:1.1.2.BUILD-SNAPSHOT' }}apply plugin: 'java'apply plugin: 'war'apply plugin: 'spring-boot'war { baseName = 'companies' version = '0.1'}repositories { mavenCentral()}dependencies { compile 'org.springframework.boot:spring-boot-starter-web' //Required dependency for JSP providedRuntime 'org.apache.tomcat.embed:tomcat-embed-jasper'} |
If you are new to Gradle, I recommend you to read about it somewhere else, e.g. on official site. It’s really nice and practical tool. It can do everything what Maven do, but without XML =)
Spring Boot initialisation
Now we can setup the Spring Boot on a java code level.
01 02 03 04 05 06 07 08 09 10 11 12 13 14 15 16 17 | package com.companies;import org.springframework.boot.SpringApplication;import org.springframework.boot.autoconfigure.EnableAutoConfiguration;import org.springframework.context.annotation.ComponentScan;import org.springframework.context.annotation.Configuration;@Configuration@ComponentScan@EnableAutoConfigurationpublic class CompanyApplication { public static void main(String[] args) { SpringApplication.run(CompanyApplication.class, args); }} |
That’s it, now you can start develop your business logic. Just kidding, we need to put some extra configs related to view resolving.
01 02 03 04 05 06 07 08 09 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 | package com.companies.config;import org.springframework.context.annotation.Bean;import org.springframework.context.annotation.Configuration;import org.springframework.web.servlet.config.annotation.DefaultServletHandlerConfigurer;import org.springframework.web.servlet.config.annotation.EnableWebMvc;import org.springframework.web.servlet.config.annotation.WebMvcConfigurerAdapter;import org.springframework.web.servlet.view.InternalResourceViewResolver;@Configuration@EnableWebMvcpublic class WebMvcConfig extends WebMvcConfigurerAdapter{ @Override public void configureDefaultServletHandling(DefaultServletHandlerConfigurer configurer) { configurer.enable(); } @Bean public InternalResourceViewResolver viewResolver() { InternalResourceViewResolver resolver = new InternalResourceViewResolver(); resolver.setPrefix("WEB-INF/pages/"); resolver.setSuffix(".jsp"); return resolver; }} |
After you created the class published above, you can go ahead with controller development.
Controller & View
01 02 03 04 05 06 07 08 09 10 11 12 13 14 15 16 17 18 19 20 21 22 | package com.companies.controller;import org.springframework.stereotype.Controller;import org.springframework.web.bind.annotation.RequestMapping;import org.springframework.web.bind.annotation.RequestMethod;import org.springframework.web.servlet.ModelAndView;@Controllerpublic class HelloWorldController { @RequestMapping(value = "/hello", method = RequestMethod.GET) public ModelAndView hello() { ModelAndView mav = new ModelAndView(); mav.setViewName("hello"); String str = "Hello World!"; mav.addObject("message", str); return mav; }} |
And corresponding view hello.jsp for the controller:
1 2 3 4 5 6 7 8 | <html><head> <title>Hello world page</title></head><body> <h1>${message}</h1></body></html> |
I hope it wan’t hard to repeat all these steps.
Run Spring Boot application
The last thing which we have to do in this tutorial is launch of the application. Hence I use Gradle, and in our build.gradle file I specified that the application need to be package as WAR file – I need to run build and run war file.
Here is how it looks like in IDEA:
Result you can see here localhost:8080/hello
If you want to perform start of the app more simply, just run the CompanyApplication.class
This approach is more preferable compering with the first one.
