在Spring Boot中如何通过不同的微服务在两个实体之间建立关系? [英] How To Make Relations Between Two Entities From Different Microservices In Spring Boot?

问题描述

我正在尝试使用 Microservice Architecture 创建一个简单的 Spring Boot 网络应用.

I am trying to make a simple Spring Boot web app using Microservice Architecture.

我有两个微服务，其实体定义如下:

I have two microservices with entities as defined below:

Microservice 1 :

@Entity
public class Article {

    @Id
    @GeneratedValue(strategy = GenerationType.IDENTITY)
    private Long id;

    private String title;

    private String Content;

}

和

Microservice 2 :

@Entity
public class Tag {

    @Id
    @GeneratedValue(strategy = GenerationType.IDENTITY)
    private Long id;

    private String title;
}

现在，我想在我的网关中这两个实体之间建立多对多关系.

Now I want to have a Many To Many relation between these two entities in my Gateway.

我曾尝试使用伪装客户端，如下所示:

I had tried to use feign client as below:

Gateway :

@FeignClient(value = "article-service")
public interface ArticleClient {

    @RequestMapping(value = "/articles/", method = RequestMethod.GET)
    Set<Article> getArticleById(@RequestParam("id") Long id);

}

@FeignClient(value = "tag-service")
public interface TagClient {

    @RequestMapping(value = "/tags/", method = RequestMethod.GET)
    Tag getTagById(@RequestParam("id") Long id);

}

并在我的网关中定义 Article 和 Tag 实体，如下所示:

And defined Article and Tag entities in my Gateway like this:

Gateway :

@JsonIgnoreProperties(ignoreUnknown = true)
public class Entry {

    private Long id;

    private String title;

    private String Content;

    @ManyToMany(cascade = CascadeType.ALL)
    @JoinTable(name = "article_tag",
        joinColumns = @JoinColumn(name = "article_id", referencedColumnName = "id"),
        inverseJoinColumns = @JoinColumn(name = "tag_id",
                referencedColumnName = "id"))
    private Set<Tag> tags;
}


@JsonIgnoreProperties(ignoreUnknown = true)
public class Tag {
    private Long id;

    private String title;

    @ManyToMany(mappedBy = "tags")
    private Set<Article> articles;
}

我的数据库( Postgres )中有一个名为 article_tag 的表.

I have a table named article_tag in my database (Postgres).

现在如何在网关中定义我的存储库? 如何编写getArticlesByTagId()或getTagsByArticleId()函数? 我尽我所能使这种关系正常运转，但我认为他们不会相处的:)

Now how can I define my repositories in the Gateway? How to write getArticlesByTagId() or getTagsByArticleId() functions? I did whatever I could to make this relation work but I think they are not going to get along with each other :)

推荐答案

您想要的东西根本就不可能，您有2个不同的应用程序，每个实体在其上下文中都有自己的生命.想象一下服务中断的情况，您将如何处理?

It just impossible what you want, you have 2 differents applications, each entity has its own life in its context. Imagine the case where a service is down, how would you do?

如果微服务与另一个微服务紧密相连，则应修改架构.

If a microservice is closely linked to another one, you should revise your architecture.

要解决此类问题，请在每个实体中添加一个标识符，以标识哪个标签属于某个条目，反之亦然，您可以使用这些标识符来请求数据.

To solve this kind of problem, add an identifier in each entity to identify which Tag belongs to an Entry and vice-versa, you can request your data using those identifiers.

这篇关于在Spring Boot中如何通过不同的微服务在两个实体之间建立关系?的文章就介绍到这了，希望我们推荐的答案对大家有所帮助，也希望大家多多支持IT屋！