WAR / JAR文件上的Spring Boot问题

Question

After a lot of head-scratching and going round in circles at websites I managed to get my Spring boot RESTful webservice deployed as a war file into Tomcat, using gradle. It was very much simpler than the documentation or other websites make out.

However, I just have a few questions:

1. How can I remove the bloat of spring from my 13Mb file and instead use a shared/deployed Spring version instead, to more easily support updating libraries?

2. Why is embedded tomcat still put into my war file (under WEB-INF\\lib-provided)?

3. Is there a way to also have the simpler jar version built for development purposes?

4. For a production system how is a jar produced file as good as a war file deployed to a container - you cannot easily modify configuration, you cannot scale it (in terms or load balancing the web server) and there is no management front-end to it. If the intent in spring (or spring boot) is to really create self-contained micro servers I still can't understand scaling it or even how you run a jar in Windows that is not a console application...

Here are the salient points of my files:

apply plugin: 'java'
apply plugin: 'org.springframework.boot'
apply plugin: 'war'

dependencies {
    compile("org.springframework.boot:spring-boot-starter-web")
    testCompile('org.springframework.boot:spring-boot-starter-test')
    providedRuntime 'org.springframework.boot:spring-boot-starter-tomcat'
}

Code:

@SpringBootApplication
public class Application extends SpringBootServletInitializer {

    public static void main(String[] args)  {
        SpringApplication.run(Application.class, args);
    }

    @Override
    protected SpringApplicationBuilder configure(SpringApplicationBuilder builder) {
        return builder.sources(Application.class);
    }

}

Thanks.

Answer 1

This should probably be several questions, so I'll (try to) answer the ones I can. I don't use Gradle, but I know Maven pretty well and the principles are the same.

1 . I don't know why a 13Mb jar is cause for concern, but you may be able to declare the dependency as compileOnly scope. Assuming the classpath of the server has the needed dependency available, this should work, though I've never tested it.

There are other potential issues here, however. Your goal: "use a shared/deployed Spring version instead, to more easily support updating libraries?" seems like a good idea, until you update the version on your server and it breaks your applications. It's much safer for each application to manage its own dependencies and deploy a dependency upgrade (as a new version of the application) only after it's been tested.

2. The embedded Tomcat is a dependency included in spring-boot-starter-web . You should be able to exclude it this way:

configurations {
    runtime.exclude module: 'spring-boot-starter-tomcat'
}

3. How do you define simpler? Again, not seeing the issue, but it seems like a bad idea anyway. I'd want whatever I'm working on to exactly mirror (Or as closely as possible) what I'm going to be putting into production.

4. There are pros and cons to any approach. You use what is best for your situation. A JAR can be self-contained, and for a small service, maybe that's better.

Answer 2

if your working with maven then creating spring-boot war file needs deployment discriptor file(web.xml) or its equalent java base configuration like initializer class for this configuration below snippet code you have write to make war file as below

@SpringBootApplication
public class Application extends SpringBootServletInitializer {

    public static void main(String[] args)  {
        SpringApplication.run(Application.class, args);
    }

    @Override
    protected SpringApplicationBuilder configure(SpringApplicationBuilder builder) {
        return builder.sources(Application.class);
    }

}

and exclude the default embedded server dependecy, and if packaging is jar then change the jar to war and then run the maven goal like maven clean install then you will get war file