springboot-Complete guide to package springboot apps as WAR and deploy to tomcat

1. The purpose of this post

This post would demo how to package the springboot app as a WAR file, and then it can be deployed to tomcat.

2. Environments

• springboot 1.x and 2.x(for example 2.1.5.RELEASE)

3. The solution

3.1 Change the build plugins in your POM

We must add the maven-war-plugin to your POM:

<build>
    <finalName>${artifactId}</finalName>
    <plugins>
        <plugin>
            <groupId>org.springframework.boot</groupId>
            <artifactId>spring-boot-maven-plugin</artifactId>
            <executions>
                <execution>
                    <goals>
                        <goal>repackage</goal>
                    </goals>
                    <configuration>
                        <classifier>exec</classifier>
                    </configuration>
                </execution>
            </executions>
        </plugin>

        <plugin>
            <groupId>org.apache.maven.plugins</groupId>
            <artifactId>maven-war-plugin</artifactId>
            <version>3.0.0</version>
        </plugin>
    </plugins>
</build>

3.2 Add some settings to your POM

<artifactId>springboot2-jdbctemplate</artifactId>

<packaging>war</packaging>

<properties>
    <project.build.sourceEncoding>UTF-8</project.build.sourceEncoding>
    <java.version>1.8</java.version>
    <start-class>springboot.dao.MainApp</start-class>
</properties>

3.3 Add some dependencies to your POM

<dependency>
    <groupId>org.springframework.boot</groupId>
    <artifactId>spring-boot-starter-web</artifactId>
</dependency>

<dependency>
    <groupId>org.springframework.boot</groupId>
    <artifactId>spring-boot-starter-tomcat</artifactId>
    <scope>provided</scope>
</dependency>

3.3 The whole POM.xml

<?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>

    <artifactId>springboot2-jdbctemplate</artifactId>

    <packaging>war</packaging>

    <properties>
        <project.build.sourceEncoding>UTF-8</project.build.sourceEncoding>
        <java.version>1.8</java.version>
        <start-class>springboot.dao.MainApp</start-class>
    </properties>

    <dependencies>
        <dependency>
            <groupId>mysql</groupId>
            <artifactId>mysql-connector-java</artifactId>
            <version>5.1.38</version>
        </dependency>
        <dependency>
            <groupId>org.springframework.boot</groupId>
            <artifactId>spring-boot-starter-jdbc</artifactId>
        </dependency>
        <dependency>
            <groupId>org.springframework.boot</groupId>
            <artifactId>spring-boot-starter-web</artifactId>
        </dependency>
        <dependency>
            <groupId>org.springframework.boot</groupId>
            <artifactId>spring-boot-starter-tomcat</artifactId>
            <scope>provided</scope>
        </dependency>

    </dependencies>

    <dependencyManagement>
        <dependencies>
            <dependency>
                <!-- Import dependency management from Spring Boot -->
                <groupId>org.springframework.boot</groupId>
                <artifactId>spring-boot-dependencies</artifactId>
                <version>2.1.5.RELEASE</version>
                <type>pom</type>
                <scope>import</scope>
            </dependency>
        </dependencies>
    </dependencyManagement>

    <build>
        <finalName>${artifactId}</finalName>
        <plugins>
            <plugin>
                <groupId>org.springframework.boot</groupId>
                <artifactId>spring-boot-maven-plugin</artifactId>
                <executions>
                    <execution>
                        <goals>
                            <goal>repackage</goal>
                        </goals>
                        <configuration>
                            <classifier>exec</classifier>
                        </configuration>
                    </execution>
                </executions>
            </plugin>

            <plugin>
                <groupId>org.apache.maven.plugins</groupId>
                <artifactId>maven-war-plugin</artifactId>
                <version>3.0.0</version>
            </plugin>
        </plugins>
    </build>
</project>

3.4 Change your Main class

The main class of your springboot app must do some changes as follows:

import org.springframework.boot.SpringApplication;
import org.springframework.boot.autoconfigure.SpringBootApplication;
import org.springframework.boot.builder.SpringApplicationBuilder;
import org.springframework.boot.web.servlet.support.SpringBootServletInitializer;

@SpringBootApplication
public class MainApp extends SpringBootServletInitializer {
    public static void main(String[] args) {
        SpringApplication.run(MainApp.class, args);
    }

    @Override
    protected SpringApplicationBuilder configure(SpringApplicationBuilder builder) {
        return builder.sources(MainApp.class);
    }
}

The key points are:

• extends SpringBootServletInitializer to make your app known by tomcat web container
• override configure method to simply register our class as a configuration class of the application

3.5 Build your WAR file

mvn clean package -o

Then you should get a WAR file in your target directory like this:

➜  target ✗ ls *.war 
springboot2-jdbctemplate-exec.war springboot2-jdbctemplate.war
➜  target ✗ 

3.6 Deploy your WAR file to tomcat

Just put your springboot2-jdbctemplate-exec.war in the webapps of your tomcat directory.

start your tomcat :

bin/catalina.sh run

Wait for a while and then visit the web like this:

➜  springboot2-jdbctempalte ✗ curl http://localhost:8080/springboot2-jdbctemplate-exec/cityApi/cities 

Remember to add the springboot2-jdbctemplate-exec to your url address.