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Updated on 2025-04-12

Interpretation of the relationship between SpringBoot and Tomcat

The relationship between Spring Boot and Tomcat can be explained in detail from multiple perspectives, including how they work, how they work, and how they work together. The following is a detailed analysis:

Introduction to Spring Boot

Spring Boot is a development tool based on the Spring framework. Its goal is to simplify the development of Spring applications. Spring Boot provides many out-of-the-box configurations, eliminating tedious XML configurations and simplifying the development process with automated configurations. It also provides many features such as embedded server support, production-level monitoring, Spring Boot Actuator, and more.

One of the core features of Spring Boot is its ability to embed a web server. It supports multiple web servers such as Tomcat, Jetty, and Undertow. We can choose one of the embedded servers so that the application can run as a standalone Java application without the need to be deployed to an external server.

Tomcat's introduction

Tomcat is an open source web server, which is a Servlet and JSP container launched by Apache Software Foundation. Tomcat implements some standards in the Java EE specification (mainly Servlets and JSPs) for handling requests and responses to web applications.

Tomcat itself is not a complete Java EE application server, it does not support other specifications of Java EE such as EJB and JMS. However, it is a very lightweight container that is widely used in the deployment of many web applications. It can run in standalone mode or be integrated with other Java EE containers.

The relationship between Spring Boot and Tomcat

The relationship between Spring Boot and Tomcat is mainly reflected in Spring Boot's embedded support for Tomcat. The following are detailed instructions:

(1) Spring Boot Inline Tomcat

Spring Boot provides the functionality of embedded web servers, and the most commonly used is embedded Tomcat. Embedded Tomcat is a key feature of Spring Boot, meaning that Spring Boot applications can run as a standalone executable JAR or WAR file without the need for a separate application server.

  • Default configuration: Spring Boot uses Tomcat as the embedded web server by default, so when you create a Spring Boot web application, you do not need to install or configure Tomcat separately by default.
  • Automated configuration: Spring Boot will automatically configure Tomcat as a web container. During development, you only need to pay attention to the business logic of the application. Tomcat automatically starts and listens for HTTP requests.
  • Run independently: Spring Boot packages the application into a separate JAR file throughjava -jarCommands can run without the need to be deployed on external servers such as Tomcat like traditional Java web applications.

(2) How to use with external Tomcat

Although Spring Boot uses inline Tomcat by default, it still supports traditional web application deployment methods. Developers have the option to deploy Spring Boot apps to external Tomcat servers.

Generate WAR file: Spring Boot supports packaging applications into WAR files and deploying them to external Tomcat servers. In this way, Tomcat handles HTTP requests as the web server, while Spring Boot serves as the business logic and web layer of the application.

Configuration method：

For example,Configuration:

<packaging>war</packaging>

existSpringBootServletInitializerMedium coverageconfiguremethod:

@SpringBootApplication
public class Application extends SpringBootServletInitializer {

    @Override
    protected SpringApplicationBuilder configure(SpringApplicationBuilder application) {
        return ();
    }

    public static void main(String[] args) {
        (, args);
    }
}
  • ReviseorConfiguration file,spring-boot-starter-webThe packaging method is modified from JAR to WAR.
  • Use on the application's entry classSpringBootServletInitializerInitialize the configuration.

(3) The main differences between Spring Boot and Tomcat

Although Tomcat is the default embedded web container for Spring Boot, there are some differences between the two:

Different functional positioning：

  • Spring BootThe main focus is on simplifying the development process of Spring applications, providing embedded Web servers, and simplifying application configuration and deployment.
  • TomcatIt is mainly a web server that handles HTTP requests, Servlet requests, and responses, but it does not directly involve the business logic development of the application.

How to use：

  • Spring BootAutomatic configuration, embedded server support and quick startup features allow developers to package applications into a JAR file or WAR file and throughjava -jarOr run the application by deploying to an external server.
  • TomcatIt is a standalone web server that usually requires manual installation and configuration and deploy WAR files to Tomcat.

Configuration flexibility：

  • In Spring Boot, Tomcat is embedded and automatically configured, and developers do not need to manually configure the details of Tomcat (such as ports, thread pools, etc.), unless there is a special requirement. Spring Boot providesorFiles to easily configure Tomcat.
  • In traditional Tomcat environments, all configurations (such as ports, memory, thread pools, etc.) usually need to be passedSet the configuration files manually.

(4) How to configure Tomcat-related parameters

Spring Boot provides some commonly used configuration items that developers can useorFile to configure Tomcat-related properties. For example:

  • Modify the port：
=8081
  • Modify the context path：
-path=/myapp
  • Configure Tomcat's connection pool(such as the maximum number of connections):
-connections=200
  • Modify the thread pool configuration：
=100
-spare=10

Through these configurations, Spring Boot allows developers to adjust the default settings of Tomcat to meet different performance requirements and usage scenarios.

Summarize

  • Embedded support: Spring Boot has built-in Tomcat as a web server by default, allowing developers to easily create self-contained web applications without installing and configuring an external Tomcat server.
  • Flexible configuration: Spring Boot provides a series of configuration options that can control the behavior of Tomcat, and developers can adjust it according to their needs.
  • Traditional deployment: Although Spring Boot provides an embedded server, developers can still deploy Spring Boot applications as WAR files to external Tomcat servers.
  • Simplify development: The goal of Spring Boot is to simplify the development and deployment process of applications. Tomcat, as the default embedded web server, greatly simplifies the up and running of web applications.

The combination of Spring Boot and Tomcat allows us to quickly and easily develop, deploy and run Java Web applications, which not only supports embedded run modes but also allows deployment on traditional web servers, providing flexibility and efficiency.

The above is personal experience. I hope you can give you a reference and I hope you can support me more.