SpringBootServletInitializer tutorial
last modified July 6, 2020
SpringBootServletInitializer tutorial shows how to deploy a Spring Boot application from a traditional WAR deployment.
The current trend is to deploy Spring Boot application from an executable JAR. (See the Spring Boot first web application for details how to start a simple web application from JAR.)
Spring is a popular Java application framework. Spring Boot is an effort to create stand-alone, production-grade Spring based applications with minimal effort.
SpringBootServletInitializer
SpringBootServletInitializer
is an interface to run SpringApplication
from a traditional WAR deployment. It binds Servlet, Filter and ServletContextInitializer
beans from the application context to the server.
SpringBootServletInitializer example
The application creates a simple Spring Boot RESTful application and packages it into a WAR.
pom.xml src ├───main │ ├───java │ │ └───com │ │ └───zetcode │ │ │ Application.java │ │ └───controller │ │ MyController.java │ └───resources └───test └───java
This is the project structure.
<?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>servletinitializer</artifactId> <version>1.0-SNAPSHOT</version> <packaging>war</packaging> <properties> <project.build.sourceEncoding>UTF-8</project.build.sourceEncoding> <maven.compiler.source>11</maven.compiler.source> <maven.compiler.target>11</maven.compiler.target> </properties> <parent> <groupId>org.springframework.boot</groupId> <artifactId>spring-boot-starter-parent</artifactId> <version>2.1.1.RELEASE</version> </parent> <dependencies> <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>
This is the Maven build file. The spring-boot-starter-web
is starter for
building web, including RESTful, applications using Spring MVC.
The application is packaged into a WAR file.
package com.zetcode.controller; import org.springframework.http.MediaType; import org.springframework.web.bind.annotation.GetMapping; import org.springframework.web.bind.annotation.RestController; @RestController public class MyController { @GetMapping(value = "/", produces = MediaType.TEXT_PLAIN_VALUE) public String index() { return "Hello there"; } }
This is the controller class for the Spring Boot web application. A controller is decorated with
the @Restontroller
annotation.
@GetMapping(value = "/", produces = MediaType.TEXT_PLAIN_VALUE) public String index() { return "Hello there"; }
A GET request to the home page returns a string. The binding is done with @GetMapping
.
package com.zetcode; import org.springframework.boot.SpringApplication; import org.springframework.boot.autoconfigure.SpringBootApplication; import org.springframework.boot.web.servlet.support.SpringBootServletInitializer; @SpringBootApplication public class Application extends SpringBootServletInitializer { public static void main(String[] args) { SpringApplication.run(Application.class, args); } }
The Application
sets up the Spring Boot application. It extends
from SpringBootServletInitializer
so that it can be deployed as
a WAR.
The application can be run both by deploying the WAR on a Tomcat server and executing it as a self-executable web archive with embedded Tomcat.
In this tutorial, we have created our first Spring Boot web application deployable from a traditional WAR.
List Spring Boot tutorials.