Spring REST API对连接表的响应

Question

I have a MySQL DB and a SpringBoot application running on Tomcat. This is a personal project of mine and my first experience designing REST services. I have been trying to create my POJOs to match the database, but this particular object is creating some doubts.

Here are the primary database tables:

• player (id, description)
• campaign (id, description)
• resource (id, description, resource_type_id)
• resource_type (id, description)
• component (id, description)

...and following junction tables:

• player_resource (id, player_id, resource_id): a player may have many resources, and a resource may belong to many players.
• campaign_resource (id, campaign_id, resource_id): a campaign may have many resources and a resource may belong to many campaigns.
• resource_component (id, resource_id, component_id): a resource may have many components and a component may belong to many resources

I'm sort of lost on how I should be designing my JSON response and the corresponding POJO(s) for the Resource object specifically.

What I'm thinking so far is to have three separate URI:

1. .../api/resources/{uuid} : Returns the specific Resource.
2. .../api/campaigns/{uuid}/resources : Returns which resources are available in the supplied campaign. As an aside, players exist within the scope of a campaign so this particular API ultimately determines what's available to a player to obtain in the course of their existence.
3. .../api/players/{uuid}/resources : Returns which resources the player currently has in their inventory.

I created a single POJO for Resource:

public class Resource {

    private String resourceId;
    private String shortDescription;
    private String longDescription;
    private ResourceType resourceType;
    private List<Component> components;

    // getters and setters

}

I created two additional POJOs for CampaignResource and PlayerResource:

public class CampaignResource {

    private String campaignResourceId;
    private Resource resource;

    // getters and setters

}

public class PlayerResource {

    private String playerResourceId;
    private Resource resource;

    // getters and setters

}

I expect URI #1 and #2 to return the same layout, but I have redundancy concerns with URI #3. URI #2 may return ten Resources which is fine and expected, but URI #3 could return hundreds depending on what a player is carrying around.

The only information I really need when calling URI #3 are the player_resource_id, resource_id, and resource_type_id fields. I do not need to know what components comprise a resource because that information is brought back in a much more manageable fashion using either URI #1 or URI #1.

I'm afraid to create separate "base" Resource POJOs since I feel obligated to follow some form of canonical modeling. Could I use something like a JsonView and separate Resource RowMappers based on whether it's URI #1, #2, or #3? I could implement some form of paging, but it's still a lot of redundant data. How would a veteran REST developer approach this?

Answer 1

Why do you need to create separate classes that contain resource for each REST API. Just return one Resource for #1 and list of Resource(s) for #2 and #3.

Answer 2

I think that if you want to know about RESTful API's this post will help a lot. Specifically about what you are asking, look in the topic Limiting which fields are returned by the API :

Use a fields query parameter that takes a comma separated list of fields to include.

For Example:

GET /tickets?fields=id,subject,customer_name,updated_at&state=open&sort=-updated_at

Here you can find how Google, Facebook and LinkdIn do.

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