Spring Boot WebApplicationType
Spring Boot WebApplicationType tutorial presents various types of web applications in a Spring Boot application. The example shows how to set the WebApplicationType.
Spring Boot WebApplicationType
last modified July 20, 2023
Spring Boot WebApplicationType tutorial presents various types of web applications in a Spring Boot application. The example shows how to set the WebApplicationType.
Spring Boot is a popular application framework for creating enterprise application in Java, Kotlin, or Groovy.
WebApplicationType
The WebApplicationType is an enumeration of possible types of web applications. There are three possible values:
- NONE - the application should not run as a web application and should not start an embedded web server.
- REACTIVE - the application should run as a reactive web application and should start an embedded reactive web server.
- SERVLET - the application should run as a servlet-based web application and should start an embedded servlet web server.
Spring Boot example
In the following application, we define the web application type of a Spring Boot application.
build.gradle … src ├── main │ ├── java │ │ └── com │ │ └── zetcode │ │ └── Application.java │ └── resources └── test └── java
This is the project structure of the Spring Boot application.
build.gradle
plugins { id ‘java’ id ‘org.springframework.boot’ version ‘3.1.1’ id ‘io.spring.dependency-management’ version ‘1.1.0’ }
group = ‘com.zetcode’ version = ‘0.0.1-SNAPSHOT’
java { sourceCompatibility = ‘17’ }
repositories { mavenCentral() }
dependencies { implementation ‘org.springframework.boot:spring-boot-starter-webflux’ implementation ‘org.springframework.boot:spring-boot-starter-web’ }
test { useJUnitPlatform() }
In the build.gradle file, we have dependencies for a classic servlet and reactive web application.
com/zetcode/Application.java
package com.zetcode;
import org.springframework.boot.CommandLineRunner; import org.springframework.boot.WebApplicationType; import org.springframework.boot.autoconfigure.SpringBootApplication; import org.springframework.boot.builder.SpringApplicationBuilder; import org.springframework.context.annotation.Bean; import org.springframework.context.annotation.Configuration; import org.springframework.stereotype.Component; import org.springframework.web.bind.annotation.GetMapping; import org.springframework.web.bind.annotation.RestController; import org.springframework.web.reactive.function.server.RouterFunction; import org.springframework.web.reactive.function.server.ServerResponse;
import static org.springframework.web.reactive.function.BodyInserters.fromValue; import static org.springframework.web.reactive.function.server.RequestPredicates.GET; import static org.springframework.web.reactive.function.server.RouterFunctions.route; import static org.springframework.web.reactive.function.server.ServerResponse.ok;
@SpringBootApplication public class Application {
public static void main(String[] args) {
new SpringApplicationBuilder(Application.class)
.web(WebApplicationType.SERVLET)
.run(args);
}
}
@RestController class MyController {
@GetMapping("/")
public String hello() {
return "Home page";
}
}
@Configuration class MyRoutes {
@Bean
RouterFunction<ServerResponse> about() {
return route(GET("/about"), request -> ok().body(fromValue("About page")));
}
}
@Component class MyRunner implements CommandLineRunner {
@Override
public void run(String... args) throws Exception {
System.out.println("Hello there!");
}
}
In the Application, we define the Spring Boot application and set up a classic web rest point, a reactive route and a commandline runner.
new SpringApplicationBuilder(Application.class) .web(WebApplicationType.SERVLET) .run(args);
We define the web application type using the SpringApplicationBuilder. For the WebApplicationType.SERVLET, the reactive route is not available.
$ ./gradlew bootRun
We start the application.
$ curl localhost:8080/ Home page
The classic servlet rest point is active.
In this article we have worked with a Spring Boot WebApplicationType.
Author
My name is Jan Bodnar, and I am a passionate programmer with extensive programming experience. I have been writing programming articles since 2007. To date, I have authored over 1,400 articles and 8 e-books. I possess more than ten years of experience in teaching programming.
