spring-boot - How to convert plain java main method program on docker

Question

• I wanted to migrate/run old java code to docker using Jenkins.

  1. It is structured to run using normal main method of java (Jar file having main method is executed through some script).

  2. Its making use of spring.xml(applicationContext.xml) files with spring-context-2.5.xsd

  3. Uses properties file for all configurations.

• Questions as I am looking for recommendations now on:

  1. Does this project needs to be migrated to spring-boot application for migrating to/creating docker image?

  2. If yes, please have a look at current code block

  3. Do I need to replace properties files by yml files?

• Current code of main class can be framed as :

public class SIIRunner {   

    public static void main(String[] args){   

        String envStr = null;
        if (args != null && args.length > 0) {
            envStr = args[0];
        }

        ApplicationContext ctx = new ClassPathXmlApplicationContext("applicationContext.xml");
        SIIExecutor siiExecutor= (SIIExecutor) ctx.getBean("SIIExecutor");
        siiExecutor.pollAndOperate();
    }
}

标签： spring-bootdocker

Answer 1

@SpringBootApplication
public class Application {
    public static void main(String[] args) throws Exception {
        ApplicationContext app = SpringApplication.run(Application.class, 
         args);//init the context
        SIIExecutor siiExecutor = (SIIExecutor) 
         app.getBean(SIIExecutor.class);//get the bean by type
    }
    @Bean // this method is the equivalent of the <bean/> tag in xml
    public SIIExecutor getBean(){
         return new SIIExecutor();
    }
}

As long as you are starting with a base @Configuration class to begin with, which it maybe sounds like you are with @SpringBootApplication, you can use the @ImportResource annotation to include an XML configuration file as well.

@SpringBootApplication
@ImportResource("classpath:beanFileName.xml")
public class SpringConfiguration {
  //
}

Spring boot ideal concept is avoid xml file. but if you want to keep xml bean, you can just add @ImportResource("classPath:beanFileName.xml")

I would recommend remove the beanFileName.xml file. and, convert this file to spring annotation based bean. So, whatever class has been created as bean. Just write @Service or @Component annotation before class name. for example:

XML based:

<bean ID="id name" class="com.example.MyBean">

Annotation based:

@Service or @Component
class MyBean {
}

And, add @ComponentScan("Give the package name").

This is the best approach. Hope this helps.