The rest of these answers are out of date and/or over the top complicated for something that should be simple IMO (how long has gzip been around for now? longer than Java...) From the docs:

In application.properties 1.3+

# 🗜️🗜️🗜️
server.compression.enabled=true
# opt in to content types
server.compression.mime-types=application/json,application/xml,text/html,text/xml,text/plain,application/javascript,text/css
# not worth the CPU cycles at some point, probably
server.compression.min-response-size=10240 

In application.properties 1.2.2 - <1.3

server.tomcat.compression=on
server.tomcat.compressableMimeTypes=application/json,application/xml,text/html,text/xml,text/plain,application/javascript,text/css

Older than 1.2.2:

@Component
public class TomcatCustomizer implements TomcatConnectorCustomizer {

  @Override
  public void customize(Connector connector) {
    connector.setProperty("compression", "on");
    // Add json and xml mime types, as they're not in the mimetype list by default
    connector.setProperty("compressableMimeType", "text/html,text/xml,text/plain,application/json,application/xml");
  }
}

Also note this will ONLY work if you are running embedded tomcat:

If you plan to deploy to a non embedded tomcat you will have to enable it in server.xml http://tomcat.apache.org/tomcat-9.0-doc/config/http.html#Standard_Implementation

IRL Production Note:

Also to avoid all of this consider using a proxy/load balancer setup in front of Tomcat with nginx and/or haproxy or similar since it will handle static assets and gzip MUCH more efficiently and easily than Java/Tomcat's threading model.

You don't want to throw 'cat in the bath because it's busy compressing stuff instead of serving up requests (or more likely spinning up threads/eating CPU/heap sitting around waiting for database IO to occur while running up your AWS bill which is why traditional Java/Tomcat might not be a good idea to begin with depending on what you are doing but I digress...)

refs: https://docs.spring.io/spring-boot/docs/current-SNAPSHOT/reference/html/howto.html#how-to-enable-http-response-compression

https://github.com/spring-projects/spring-boot/issues/2031

On recents versions in application.yml config:

---

spring:
  profiles: dev

server:
  compression:
    enabled: true
    mime-types: text/html,text/css,application/javascript,application/json

---

This is basically the same solution as @andy-wilkinson provided, but as of Spring Boot 1.0 the customize(...) method has a ConfigurableEmbeddedServletContainer parameter.

Another thing that is worth mentioning is that Tomcat only compresses content types of text/html, text/xml and text/plain by default. Below is an example that supports compression of application/json as well:

@Bean
public EmbeddedServletContainerCustomizer servletContainerCustomizer() {
    return new EmbeddedServletContainerCustomizer() {
        @Override
        public void customize(ConfigurableEmbeddedServletContainer servletContainer) {
            ((TomcatEmbeddedServletContainerFactory) servletContainer).addConnectorCustomizers(
                    new TomcatConnectorCustomizer() {
                        @Override
                        public void customize(Connector connector) {
                            AbstractHttp11Protocol httpProtocol = (AbstractHttp11Protocol) connector.getProtocolHandler();
                            httpProtocol.setCompression("on");
                            httpProtocol.setCompressionMinSize(256);
                            String mimeTypes = httpProtocol.getCompressableMimeTypes();
                            String mimeTypesWithJson = mimeTypes + "," + MediaType.APPLICATION_JSON_VALUE;
                            httpProtocol.setCompressableMimeTypes(mimeTypesWithJson);
                        }
                    }
            );
        }
    };
}

I have added for this:

Server compression

server.compression.enabled=true
server.compression.min-response-size=2048
server.compression.mime-types=application/json,application/xml,text/html,text/xml,text/plain

taken from http://bisaga.com/blog/programming/web-compression-on-spring-boot-application/

Spring Boot 1.4 Use this for Javascript HTML Json all compressions.

server.compression.enabled: true
server.compression.mime-types: application/json,application/xml,text/html,text/xml,text/plain,text/css,application/javascript

Enabeling GZip in Tomcat doesn't worked in my Spring Boot Project. I used CompressingFilter found here.

@Bean
public Filter compressingFilter() {
    CompressingFilter compressingFilter = new CompressingFilter();
    return compressingFilter;
}

To enable GZIP compression, you need to modify the configuration of the embedded Tomcat instance. To do so, you declare a EmbeddedServletContainerCustomizer bean in your Java configuration and then register a TomcatConnectorCustomizer with it.

For example:

@Bean
public EmbeddedServletContainerCustomizer servletContainerCustomizer() {
    return new EmbeddedServletContainerCustomizer() {
        @Override
        public void customize(ConfigurableEmbeddedServletContainerFactory factory) {
            ((TomcatEmbeddedServletContainerFactory) factory).addConnectorCustomizers(new TomcatConnectorCustomizer() {
                @Override
                public void customize(Connector connector) {
                    AbstractHttp11Protocol httpProtocol = (AbstractHttp11Protocol) connector.getProtocolHandler();
                    httpProtocol.setCompression("on");
                    httpProtocol.setCompressionMinSize(64);
                }
            });
        }
    };
}

See the Tomcat documentation for more details on the various compression configuration options that are available.

You say that you want to selectively enable compression. Depending on your selection criteria, then the above approach may be sufficient. It enables you to control compression by the request's user-agent, the response's size, and the response's mime type.

If this doesn't meet your needs then I believe you will have to perform the compression in your controller and return a byte[] response with a gzip content-encoding header.

I had the same problem into my Spring Boot+Spring Data project when invoking to a @RepositoryRestResource.

The problem is the MIME type returned; which is application/hal+json. Adding it to the server.compression.mime-types property solved this problem for me.

Hope this helps to someone else!

Add following dependency in pom.xml

<dependency>
    <groupId>net.sourceforge.pjl-comp-filter</groupId>
    <artifactId>pjl-comp-filter</artifactId>
    <version>1.6.4</version>
</dependency>

Add following bean configuration into your configuration file.

import org.springframework.boot.web.servlet.FilterRegistrationBean;
import org.springframework.context.annotation.Bean;
import org.springframework.web.servlet.DispatcherServlet;
import com.planetj.servlet.filter.compression.CompressingFilter;

@Bean
public FilterRegistrationBean<CompressingFilter> dispatcherRegistration(DispatcherServlet dispatcherServlet) {
    FilterRegistrationBean<CompressingFilter> registrationBean = new FilterRegistrationBean<>();
    registrationBean.setFilter(new CompressingFilter());
    registrationBean.setEnabled(true);
    registrationBean.addUrlPatterns("/*");
    return registrationBean;
}

CompressingFilter helps to compress the response.

You can set GZIP compression of selective endpoints using addUrlPatterns(String) method in FilterRegistrationBean. Use setUrlPatterns(Collection<String>) method in case you have multiple endpoints.

If no URL pattern is set, filter compresses all responses.

Note: this won't even need to add any properties in application.properties file.

Get the latest documentation from the below spring-docs url :

Spring-docs Embedded Server Configuration