Spring Boot - Deploy WAR file to External Tomcat

In this article, we will discuss how to deploy a Spring Boot web application WAR file to the external Tomcat servlet container.

It's very simple to configure and deploy the Spring web application war file to external Tomcat servlet container.

Please follow below three simple steps to configure and deploy the Spring web application war file to external Tomcat servlet container.

Three steps for Spring Boot WAR deployment

  1. Change the packaging type.
<packaging>war</packaging>
  1. Add spring-boot-starter-tomcat as the provided scope
  <dependency>
      <groupId>org.springframework.boot</groupId>
      <artifactId>spring-boot-starter-tomcat</artifactId>
      <scope>provided</scope>
  </dependency>
  1. Spring Boot Application or Main class extends SpringBootServletInitializer
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 Springboot2WebappJspApplication extends SpringBootServletInitializer{

    @Override
    protected SpringApplicationBuilder configure(SpringApplicationBuilder application) {
        return application.sources(Springboot2WebappJspApplication.class);
    }
 
    public static void main(String[] args) {
        SpringApplication.run(Springboot2WebappJspApplication.class, args);
    }
}
Let's develop complete step by step Spring Boot 2 Web application using JSP as View.

Table of Contents

  1. What we’ll build
  2. Tools and Technologies Used
  3. Creating and Importing a Project
  4. Packaging Structure
  5. The pom.xml File
  6. The Springboot2WebappJspApplication.java File
  7. Create a JPA Entity called User.java
  8. Create Spring Data JPA Repository - UserRepository.java
  9. Create Spring Controller - UserController.java
  10. Configuring MySQL Database and JSP View Resolver
  11. Insert SQL Script
  12. Create a JSP View - users.jsp
  13. Running the Application

1. What we’ll build

We are building a simple Spring MVC web application and JSP as a view and we will deploy this application in an external servlet container that is Tomcat.

2. Tools and Technologies Used

  • Spring Boot - 2.0.4.RELEASE
  • JDK - 1.8 or later
  • Spring Framework - 5.0.8 RELEASE
  • Hibernate - 5.2.17.Final
  • Maven - 3.2+
  • IDE - Eclipse or Spring Tool Suite (STS)
  • Tomcat - 8.5+
  • JSP
  • Bootstrap 3+

3. Creating and Importing a Project

There are many ways to create a Spring Boot application. The simplest way is to use Spring Initializr at http://start.spring.io/, which is an online Spring Boot application generator.
Look at the above diagram, we have specified following details:
  • Generate: Maven Project
  • Java Version: 1.8 (Default)
  • Spring Boot:2.0.4
  • Group: net.guides.springboot2
  • Artifact: springboot2webappjsp
  • Name: springboot2webappjsp
  • Package Name : net.guides.springboot2.springboot2webappjsp
  • Packaging: jar (This is the default value)
  • Dependencies: Web, JPA, MySQL, DevTools
Once, all the details are entered, click on Generate Project button will generate a spring boot project and downloads it. Next, Unzip the downloaded zip file and import it into your favorite IDE.

4. Packaging Structure

Once we will import generated spring boot project in IDE, we will see some auto-generated files.
  1. pom.xml
  2. resources
  3. Springboot2WebappJspApplication.java
  4. Springboot2WebappJspApplicationTests.java

5. The pom.xml File

<?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>net.guides.springboot2</groupId>
    <artifactId>springboot2-webapp-jsp</artifactId>
    <version>0.0.1-SNAPSHOT</version>
    <packaging>war</packaging>

    <name>springboot2-webapp-jsp</name>
    <description>Demo project for Spring Boot</description>

    <parent>
        <groupId>org.springframework.boot</groupId>
        <artifactId>spring-boot-starter-parent</artifactId>
        <version>2.0.4.RELEASE</version>
        <relativePath /> <!-- lookup parent from repository -->
    </parent>

    <properties>
        <project.build.sourceEncoding>UTF-8</project.build.sourceEncoding>
        <project.reporting.outputEncoding>UTF-8</project.reporting.outputEncoding>
        <java.version>1.8</java.version>
    </properties>

    <dependencies>
        <dependency>
            <groupId>org.springframework.boot</groupId>
            <artifactId>spring-boot-starter-web</artifactId>
        </dependency>
        <dependency>
            <groupId>org.springframework.boot</groupId>
            <artifactId>spring-boot-starter-data-jpa</artifactId>
        </dependency>
        <dependency>
            <groupId>org.springframework.boot</groupId>
            <artifactId>spring-boot-devtools</artifactId>
            <scope>runtime</scope>
        </dependency>
        <dependency>
            <groupId>mysql</groupId>
            <artifactId>mysql-connector-java</artifactId>
            <scope>runtime</scope>
        </dependency>
        <dependency>
            <groupId>org.springframework.boot</groupId>
            <artifactId>spring-boot-starter-test</artifactId>
            <scope>test</scope>
        </dependency>

         <!-- JSTL for JSP -->
        <dependency>
            <groupId>javax.servlet</groupId>
            <artifactId>jstl</artifactId>
        </dependency>

        <!-- Need this to compile JSP -->
        <dependency>
            <groupId>org.apache.tomcat.embed</groupId>
            <artifactId>tomcat-embed-jasper</artifactId>
            <scope>provided</scope>
        </dependency>

        <dependency>
            <groupId>org.springframework.boot</groupId>
            <artifactId>spring-boot-starter-tomcat</artifactId>
            <scope>provided</scope>
        </dependency>
        <!-- Optional, test for static content, bootstrap CSS -->
        <dependency>
            <groupId>org.webjars</groupId>
            <artifactId>bootstrap</artifactId>
            <version>3.3.7</version>
        </dependency>
    </dependencies>

    <build>
        <plugins>
            <plugin>
                <groupId>org.springframework.boot</groupId>
                <artifactId>spring-boot-maven-plugin</artifactId>
            </plugin>
        </plugins>
    </build>


</project>
Note that is above pom.xml, we have packaging type as war and tomcat starter as provided scope.

6. The Springboot2WebappJspApplication.java File

This class provides an entry point with the public static void main(String[] args) method, which you can run to start the application.
Note that SpringBootServletInitializer run a SpringApplication from a traditional WAR deployment
package net.guides.springboot2.springboot2webappjsp;

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 Springboot2WebappJspApplication extends SpringBootServletInitializer{

    @Override
    protected SpringApplicationBuilder configure(SpringApplicationBuilder application) {
        return application.sources(Springboot2WebappJspApplication.class);
    }
 
    public static void main(String[] args) {
        SpringApplication.run(Springboot2WebappJspApplication.class, args);
    }
}

7. Create a JPA Entity called User.java

package net.guides.springboot2.springboot2webappjsp.domain;

import javax.persistence.Entity;
import javax.persistence.GeneratedValue;
import javax.persistence.GenerationType;
import javax.persistence.Id;
import javax.persistence.Table;

@Entity
@Table(name = "user")
public class User {
    @Id 
    @GeneratedValue(strategy=GenerationType.AUTO)
    private Integer id;
    private String name;
 
    public User()
    {
    }

    public User(Integer id, String name)
    {
        this.id = id;
        this.name = name;
    }

    public Integer getId()
    {
        return id;
    }

    public void setId(Integer id)
    {
        this.id = id;
    }

    public String getName()
    {
        return name;
    }

    public void setName(String name)
    {
        this.name = name;
    }
}

8. Create Spring Data JPA Repository - UserRepository.java

package net.guides.springboot2.springboot2webappjsp.repositories;

import org.springframework.data.jpa.repository.JpaRepository;

import net.guides.springboot2.springboot2webappjsp.domain.User;

public interface UserRepository extends JpaRepository<User, Integer>
{

}

9. Create Spring Controller - UserController.java

package net.guides.springboot2.springboot2webappjsp.controllers;

import org.springframework.beans.factory.annotation.Autowired;
import org.springframework.stereotype.Controller;
import org.springframework.ui.Model;
import org.springframework.web.bind.annotation.RequestMapping;

import net.guides.springboot2.springboot2webappjsp.repositories.UserRepository;

@Controller
public class UserController {
    @Autowired
    UserRepository userRepo;

    @RequestMapping("/users")
    public String home(Model model) {
        model.addAttribute("users", userRepo.findAll());
        return "index";
    }
}

10. Configuring MySQL Database and JSP View Resolver

Configure application.properties to connect to your MySQL database. Let's open an application.properties file and add following database configuration to it.
spring.mvc.view.prefix: /WEB-INF/jsp/
spring.mvc.view.suffix: .jsp

logging.level.org.springframework=INFO

################### DataSource Configuration ##########################
spring.datasource.driver-class-name=com.mysql.jdbc.Driver
spring.datasource.url=jdbc:mysql://localhost:3306/users_database
spring.datasource.username=root
spring.datasource.password=root

################### Hibernate Configuration ##########################

spring.jpa.hibernate.ddl-auto=update
spring.jpa.show-sql=true

11. Insert SQL Script

Once you will run this application will create users table in a database and use below insert SQL script to populate a few records in users table.
INSERT INTO `users_database`.`user` (`id`, `name`) VALUES ('1', 'Salman');
INSERT INTO `users_database`.`user` (`id`, `name`) VALUES ('2', 'SRK');
INSERT INTO `users_database`.`user` (`id`, `name`) VALUES ('3', 'AMIR');
INSERT INTO `users_database`.`user` (`id`, `name`) VALUES ('4', 'Tiger');
INSERT INTO `users_database`.`user` (`id`, `name`) VALUES ('5', 'Prabhas');

12. Create a JSP View - users.jsp

Let's create a users.jsp view to show the list of users. Locate under webapp/WEB-INF/jsp folder.
<!DOCTYPE html>
<%@ taglib prefix="spring" uri="http://www.springframework.org/tags"%>
<%@ taglib prefix="c" uri="http://java.sun.com/jsp/jstl/core"%>
<html lang="en">
<head>

<link rel="stylesheet" type="text/css"
 href="webjars/bootstrap/3.3.7/css/bootstrap.min.css" />
<c:url value="/css/main.css" var="jstlCss" />
<link href="${jstlCss}" rel="stylesheet" />

</head>
<body>
 <div class="container">
  <header>
   <h1>Spring MVC + JSP + JPA + Spring Boot 2</h1>
  </header>
  <div class="starter-template">
   <h1>Users List</h1>
   <table
    class="table table-striped table-hover table-condensed table-bordered">
    <tr>
     <th>Id</th>
     <th>Name</th>
    </tr>
    <c:forEach var="user" items="${users}">
     <tr>
      <td>${user.id}</td>
      <td>${user.name}</td>
     </tr>
    </c:forEach>
   </table>
  </div>

 </div>

 <script type="text/javascript"
  src="webjars/bootstrap/3.3.7/js/bootstrap.min.js"></script>
</body>

</html>

13. Running the Application

  1. It is a maven project so create a war file using the following command:
mvn clean install or mvn clean package
  1. Once maven builds success then WAR file is generated under a target folder.
Just copy war file to external tomcat webapps folder and start the tomcat server.
  1. Hit this link to a browser - http://localhost:8080/springboot2-webapp-jsp/users
Note that you can change the context name from springboot2-webapp-jsp-0.0.1-SNAPSHOT to springboot2-webapp-jsp or as per your requirement.

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