使用Maven部署Spring-Boot项目，并将其进一步导入其他项目中 [英] Deploying a Spring-Boot project using Maven and further importing it in other projects

问题描述

因此，目前，我有两个项目，比如说Storefront和Dashboard，这两个项目都具有相同的POJO类，服务和一些API端点.例如，考虑一个 Student 类，我们在Storefront和Dashboard中都有该类及其服务类.此外，在不久的将来，我们将为客户实施另一个项目，即客户仪表板"，该项目将拥有几乎90％的相同资源.

So currently, I have two projects, let's say Storefront and Dashboard, and both of these projects have the same POJO classes, Services, and some API Endpoints. For example, consider a class Student, we have this class in Storefront as well as in the Dashboard along with its service class. Further, in near future, we'll be implementing another project for clients, a Client Dashboard, that'll have almost 90% of the same resources.

所以我想，如果我创建一个包含所有项目所需要的所有库的maven项目，然后根据需要将其导入.这将减少冗余，并使其他项目的权重降低.我以前曾使用项目内存储库和Dropbox作为Maven存储库，所以这次对我来说会更容易一些.

So I thought, what if I create a maven project with all the libraries I need across all projects and import them as needed. This would reduce the redundancy and would also make other projects light weighted. I've previously used the in-project repository and Dropbox as a maven repository so it'll be a bit easier for me this time.

现在的问题是:我有与 Student 相对应的 StudentRepository ，还可以与'@Autowired'注释一起使用吗?据我所知，当我运行'@SpringBootApplication'时，一切都会正常工作，但是正如我之前提到的，我将导入这些包，并且这样做，程序将通过NullPointerException导致StudentRepository的实例为null.

Now the problem is: I have the StudentRepository corresponding to the Student, which is further used with the '@Autowired' annotation right? As per my knowledge, everything will work when I run the '@SpringBootApplication' but as I previously mentioned, I'll be importing these packages, and doing so, the program will through a NullPointerException cause the instance of the StudentRepository will be null.

@SpringBootApplication
@EnableAutoConfiguration
@EntityScan
public class DemoApplication implements CommandLineRunner {

    private Logger logger = LoggerFactory.getLogger(this.getClass());

    @Autowired
    StudentRepository repository;

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

    @Override
    public void run(String... args) throws Exception {
        // This will work
        logger.info("Inserting -> {}", repository.save(new Student("studentName", "primaryKey")));
    }
    
    // This won't
    public void addAStudent(String studentName, String primaryKey) {
        repository.save(new Student(studentName, primaryKey));
    }

}

public class Test {

    public static void main(String[] args) {
        // This will throw a NullPointerException
        new DemoApplication().addAStudent("yourNameProbably", "yourSocialSecurityNumber");
    }

}

那么还有其他方法可以使这项工作吗?任何建议将不胜感激，并在此先感谢.

So is there any other way to make this work? Any suggestions will be appreciated and thanks in advance.

推荐答案

假定您有一个库FooLibrary和主应用程序FooApplication.这个想法是在FooApplication中导入FooLibrary.

Assume that you have a library FooLibrary and main application FooApplication. The idea is importing FooLibrary in FooApplication.

让我们从FooLibrary开始.因此，主要有2个重要文件.它们是FooLibraryInterface和FooLibraryConfiguration.在此示例中，我将不使用FooLibraryInterface.

Let's begin with FooLibrary. So mainly there are 2 important files. These are FooLibraryInterface and FooLibraryConfiguration. In this example I will not use FooLibraryInterface.

FooLibraryInterface是一个接口，其中包含客户端可能需要使用override和FooLibraryConfiguration来扫描和注入在FooLibrary中找到的bean的重要方法.所以，这里是

FooLibraryInterface is an interface that holds important methods that the client might need to override and FooLibraryConfiguration to scan and inject beans found in FooLibrary. So, here it follows

public interface FooLibraryInterface {
    public abstract Datasource configureDatabaseConnection();
}

FooLibraryConfiguration将如下所示:

@Configuration
@ComponentScan("package.to.scan")
public class FooLibraryConfiguration {
    @Bean
    public YourBean beanName() {
        return new YourBean();
    }
}

您可以在FooLibrary中添加所有需要的内容.现在我们的库已准备好在FooLibraryConfiguration

You can add all that you need in FooLibrary. Now our library is ready to be imported in FooApplication with the help of FooLibraryConfiguration

@SpringBootApplication
@Import(FooLibraryConfiguration.class) //this will import all the beans defined in the library
public class FooApplication {
    public static void main(String[] args) {
        SpringApplication.run(FooApplication.class, args);
    }
}

注意:如果您拥有EntityManager个托管类(实体，存储库)，则应该对主应用程序中的lib软件包进行其他扫描，因为我们不需要为单个应用程序使用不同的EntityManager .或者，您可以一起扫描所有文件( @EnableJpaRepositories 或 em.setPackagesToScan("library.entities.package"); 与@ComponentScan("base.library.package")一起保留单独的扫描)

NOTE: If you have EntityManager managed classes(entity, repository), you should do an additional scan of the lib packages in the main application, since we don't need to have different EntityManager for a single application. Or you may scan all files together (leaving individual scans from @EnableJpaRepositories or em.setPackagesToScan("library.entities.package"); with @ComponentScan("base.library.package"))

@Configuration
@EnableJpaRepositories(basePackages = { "library.repository.package" })
@EnableTransactionManagement
public class PersistenceConfig {
    @Bean
    public LocalContainerEntityManagerFactoryBean entityManagerFactory() {
        LocalContainerEntityManagerFactoryBean em = new LocalContainerEntityManagerFactoryBean();
        em.setDataSource(dataSource());
        em.setPackagesToScan("library.entities.package");

        JpaVendorAdapter vendorAdapter = new HibernateJpaVendorAdapter();
        em.setJpaVendorAdapter(vendorAdapter);
        em.setJpaProperties(additionalProperties());

        return em;
    }
    .....
}

更新

感谢您 @ keshavram-kuduwa ，您可以从 https://spring.io/guides/gs/multi-module/#_create_the_library_project

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