将 Spring 数据休息链接与同一实体上的控制器链接合并

Question

我想将 HATEAOS 链接与 Controller 和 Repository 上的方法结合起来。

@RepositoryRestController
@ResponseBody
@ExposesResourceFor(Group.class)
@RequestMapping(value = "/api/v2/groups", produces = MediaTypes.HAL_JSON_VALUE)
public class GroupController {

    @Resource
    private GroupService groupService;

    @RequestMapping(value = "/external", method = POST)
    public  @ResponseBody   PersistentEntityResource saveExternalGroup(
            @RequestBody Group newGroup,
            PersistentEntityResourceAssembler assembler) {

        return assembler.toResource(groupService.saveExternalGroup(newGroup));

    }

}

存储库：

@RepositoryRestResource(excerptProjection = GroupSummary.class)
public interface GroupDao extends DefaultDao<Group, Long> {

    @NotNull
    List<Group> findByState(@Nullable GroupState state);
...other methods...

我想实现有可能去 /api/v2/groups 并有链接到 /external。目前，仅返回来自存储库的链接：

"_links": {
    "first": {
      "href": "http://localhost:8300/api/v2/groups?page=0&size=20"
    },
    "self": {
      "href": "http://localhost:8300/api/v2/groups"
    },
    "next": {
      "href": "http://localhost:8300/api/v2/groups?page=1&size=20"
    },
    "last": {
      "href": "http://localhost:8300/api/v2/groups?page=1&size=20"
    },
    "profile": {
      "href": "http://localhost:8300/api/v2/profile/groups"
    },
    "search": {
      "href": "http://localhost:8300/api/v2/groups/search"
    }
  },

我应该如何实现上述所有内容以及类似的内容：

"external": {
          "href": "http://localhost:8300/api/v2/groups/external"
        }

或者“/external”是 POST 有问题吗？如果是这样，请用“method=GET”评论并考虑这个问题。

Answer 1

选项1：

如果是一次性的，您可以使用 Resource 类在控制器方法中添加链接。

@RequestMapping(value = "/external", method = POST)
public  @ResponseBody   PersistentEntityResource saveExternalGroup(
        @RequestBody Group newGroup,
        PersistentEntityResourceAssembler assembler) {

    PersistentEntityResource resource = assembler.toResource(groupService.saveExternalGroup(newGroup));

    // Replace with ControllerLinkBuilder call, or EntityLinks as you see fit.
    resource.add(new Link("http://localhost:8300/api/v2/groups/external","search"));

    return resource;
}

选项 2：

如果您希望将此链接添加到每个渲染的Resource<Group>，然后创建一个ResourceProcessor 组件来添加它。

@Component
public class GroupResourceProcessor implements ResourceProcessor<Resource<Group>> {

    @Override
    public Resource<Group> process(Resource<Group> groupResource) {

        // Replace with ControllerLinkBuilder call, or EntityLinks as you see fit.
        groupResource.add(new Link("http://localhost:8300/api/v2/groups/external","search"));

        return groupResource;
    }

}