Spring Boot + GZIP Compression - Hello World Example | JavaInUse

Spring Boot + GZIP - Hello World Example

In this example we will learn how to to enable compression for a Spring Boot application using GZIP.

What is GZIP? Need for it?

When a user hits the website a call is made to the server to return the requested files. If these requested files are large, it takes a longer time to reach the browser and get displayed.
Gzip compresses the webpages and style sheets before sending them over to the browser. This reduces the page loading time, less bandwidth usage and better user experience.
Consider a scenario when you visit this web site - www.javainuse.com . Then following operations are performed.
If we enable gzip compression -


This tutorial is explained in the below Youtube Video.

Lets Begin-

In this tutorial we will implement GZIP at the tomcat level. We will see how to implement this for
  • Deploying Spring Boot Application for Embedded Tomcat.
  • Deploying Spring Boot Application as war to external Tomcat.

Deploying Spring Boot Application for Embedded Tomcat

In previous example we had implemented a Spring Boot File download Example
We will be using the same example to implement GZIP.
The Maven project will be as follows-
Start the Application, and go to localhost:8080/download/file/boot.jpg We can see the image inline as follows -
In the developer tools-> network we can see that there is no encoding present.
Next create application.properties. Here we enable with following MIME types-
server.compression.enabled: true
Start the Application again, and go to localhost:8080/boot/download/file/boot.jpg
This time in developer tools-> network we can see that there is gzip encoding present.

Deploying Spring Boot Application as war to external Tomcat

Next if the application is to be deployed as a war file in external Tomcat then we will need to modify the code.
Maven project will be as follows -
Create the class that extends SpringBootServletInitializer class.
package com.javainuse;

import org.springframework.boot.builder.SpringApplicationBuilder;
import org.springframework.boot.web.support.SpringBootServletInitializer;

public class ServletInitializer extends SpringBootServletInitializer {

	protected SpringApplicationBuilder configure(SpringApplicationBuilder application) {
		return application.sources(SpringBootFileDownoad.class);

In pom.xml add the packaging as war.
<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">

		<relativePath />



Finally in the server.xml, in connector tag enable compression and specify the MIME types-
<Connector port="8080" protocol="HTTP/1.1"
			   noCompressionUserAgents="gozilla, traviata"
			   compressableMimeType="application/json,application/xml,text/html,text/xml,text/plain,application/javascript,text/css,image/jpeg" />
Compile the application, this creates a war file. Copy this file in the webapps folder and start tomcat. Go to localhost:8080/boot/download/file/boot.jpg
We can see the content is encoded as gzip.

Download Source Code

Download it -
Spring Boot Embedded Container GZIP Example
Spring Boot External Container GZIP Example