Spring Boot can package applications as either JAR or WAR files. Here is a comparison of the two:
JAR files are executable Java files that can be run on any machine with a Java Virtual Machine (JVM). They are typically used for standalone applications, such as command-line tools or desktop applications.
WAR files are web archive files that are used to deploy web applications to a web server. They contain all of the resources that the web application needs, such as HTML, CSS, JavaScript, and Java classes.
Here is a table that summarizes the key differences between JAR and WAR files:
| Characteristic | JAR file | WAR file |
|---|---|---|
| Type | Executable Java file | Web archive file |
| Usage | Standalone applications | Web applications |
| Deployment | Can be run on any machine with a JVM | Must be deployed to a web server |
| Contents | Java classes, resources, and a manifest file | Java classes, resources, a manifest file, and web.xml file |
Which one should you choose?
If you are developing a standalone application, then you should use a JAR file. If you are developing a web application, then you should use a WAR file.
However, there are some cases where you might want to use a JAR file for a web application. For example, you might want to use a JAR file if you are developing a REST API that does not need to be deployed to a web server.
How to package your Spring Boot application as a JAR or WAR file
To package your Spring Boot application as a JAR file, you can use the following command:
mvn clean package
This will create a JAR file in the target directory.
To package your Spring Boot application as a WAR file, you can use the following command:
mvn war:war
This will create a WAR file in the target directory.
Once you have packaged your application as a JAR or WAR file, you can deploy it to your target environment.