Spring Data REST 返回 EmptyCollectionEmbeddedWrapper 而不是空集合

问题描述

我正在开发基于 Spring Data REST 的服务.由于我们使用 swagger(通过 SpringFox 生成)创建前端代码这一事实，我不得不停用 HAL 格式的返回，该格式可以正常工作，但有一个例外.

I am developing a Service based on Spring Data REST. Cause of the fact that we are creating the frontend code using swagger (generated via SpringFox) I had to deactivate the return of the HAL-format which works fine with one exception.

如果请求的结果是一个空列表，则响应如下

If the result of a request is an empty list the response looks like this

{
"links": [
    {
        "rel": "self",
        "href": "http://localhost:9999/users"
    },
    {
        "rel": "profile",
        "href": "http://localhost:9999/profile/users"
    }
],
"content": [
    {
        "rel": null,
        "collectionValue": true,
        "relTargetType": "com.example.User",
        "value": []
    }
]
}

如何获取空列表作为内容?

How can I get an empty List as content?

推荐答案

为了使用 Spring HATEOAS 1.x 引入的类型，我不得不调整上一个解决方案中提供的解决方案

I have had to adapt the solution provided in the previous solution to use the types introduced by the Spring HATEOAS 1.x

这是我正在使用的代码:

This is the code I'm using:

@Component
public class ResourceProcessorEmpty implements RepresentationModelProcessor<CollectionModel<Object>> {
    @Override
    public CollectionModel<Object> process(CollectionModel<Object> resourceToThrowAway) {
        if (resourceToThrowAway.getContent().size() != 1) {
            return resourceToThrowAway;
        }
        if (!resourceToThrowAway.getContent().iterator().next().getClass().getCanonicalName().contains("EmptyCollectionEmbeddedWrapper")) {
            return resourceToThrowAway;
        }

        CollectionModel<Object> newResource = new CollectionModel<>(Collections.emptyList());
        newResource.add(resourceToThrowAway.getLinks());
        return newResource;
    }
}

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