Spring Boot WebApplicationType
last modified July 6, 2020
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.
pom.xml src ├── main │ ├── java │ │ └── com │ │ └── zetcode │ │ └── Application.java │ └── resources └── test └── java
This is the project structure of the Spring Boot application.
<?xml version="1.0" encoding="UTF-8"?> <project xmlns="http://maven.apache.org/POM/4.0.0" xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance" xsi:schemaLocation="http://maven.apache.org/POM/4.0.0 http://maven.apache.org/xsd/maven-4.0.0.xsd"> <modelVersion>4.0.0</modelVersion> <groupId>com.zetcode</groupId> <artifactId>SpringBootWebOff</artifactId> <version>1.0-SNAPSHOT</version> <packaging>jar</packaging> <properties> <java.version>13</java.version> </properties> <parent> <groupId>org.springframework.boot</groupId> <artifactId>spring-boot-starter-parent</artifactId> <version>2.2.4.RELEASE</version> </parent> <dependencies> <dependency> <groupId>org.springframework.boot</groupId> <artifactId>spring-boot-starter-webflux</artifactId> </dependency> <dependency> <groupId>org.springframework.boot</groupId> <artifactId>spring-boot-starter-web</artifactId> </dependency> </dependencies> <build> <plugins> <plugin> <groupId>org.springframework.boot</groupId> <artifactId>spring-boot-maven-plugin</artifactId> </plugin> </plugins> </build> </project>
In the Maven pom.xml
file, we have dependencies for a classic servlet
and reactive web application.
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.
$ mvn spring-boot:run
We start the application.
$ curl localhost:8080/ Home page
The classic servlet rest point is active.
In this tutorial, we have worked with a Spring Boot WebApplicationType
.
List Spring Boot tutorials.