Spring Boot: How to add another WAR files to the embedded tomcat?

Question

Spring Boot\'s embedded tomcat is very handy, for both development and deploy.

But what if an another (3rd-party) WAR file (for example, GeoServer) should be added?<

Answer 1

The accepted answer covers Spring Boot 1.x. The class mentioned is no longer present in Spring Boot 2.x. When using version 2, you need to use a different one:

    @Bean
    @ConditionalOnProperty(name = "external.war.file")
    public TomcatServletWebServerFactory servletContainerFactory(@Value("${external.war.file}") String path,
                                                                 @Value("${external.war.context:}") String contextPath) {
        return new TomcatServletWebServerFactory() {

            @Override
            protected TomcatWebServer getTomcatWebServer(Tomcat tomcat) {
                new File(tomcat.getServer().getCatalinaBase(), "webapps").mkdirs();

                Context context = tomcat.addWebapp(contextPath, path);
                context.setParentClassLoader(getClass().getClassLoader());

                return super.getTomcatWebServer(tomcat);
            }

        };
    }

Also, Spring boot enbedded Tomcat does not by default contain dependencies for JSPs. If you are using JSPs in your external war, you need to include them.

    org.apache.tomcat.embed
    tomcat-embed-jasper


    javax.servlet
    jstl

UPDATE: I've written a more detailed blog post on how to set this up for both Spring Boot 1 and 2.