Spring 5 Reactive WebClient 似乎没有反序列化参数化类型

Question

这个问题曾经的标题是“Spring 5 Reactive WebClient 消费者 HAL+JSON HATEOAS PagedResources”，但新的标题更合适。

以下代码与 RestTemplate 完美配合（参数化类型从 Spring DataREST 提供的 HATEOAS/HAL PagedResource 返回）：

// use exchange with ParameterizedTypeReference
ResponseEntity<PagedResources<Foo>> responseEntity = 
    restTemplate.exchange("/foos", HttpMethod.GET, null, 
    new ParameterizedTypeReference<PagedResources<Foo>>() {}, 
    randomServerPort, 0, 100);
// then the actual list of foos can be obtained like so
PagedResources<Foo> resources = responseEntity.getBody();
List<foo> foos = new ArrayList(resources.getContent());

这不适用于 Spring 5 Reactive WebClient：

public Mono<PagedResources<Foo>> getFoos() {
        return client.get()
            .uri("/foos").accept(MediaTypes.HAL_JSON)
            .retrieve()
            .bodyToMono(new ParameterizedTypeReference<PagedResources<Foo>>(){});
}

调用上述服务方法的控制器代码为：

@GetMapping("/foos")
public Mono<PagedResources<Foo>> getFoos() {
    return dataService.getFoos();
}

curl 的结果是：

{"links":[],"content":[],"page":null}

经过大量研究，上面的代码应该可以工作，因为参数化类型应该传递给 Jackson，就像上面显示的 RestTemplate 的情况一样。

This is looking now more like a bug. But before filing one I would like to see if someone has WebClient bodyToXXX working with parametrized types (i.e. ParameterizedTypeReference, Super Type Tokens, etc.)

Note there is a test for this in the WebClient code but maybe the embedded type ref (PagedResources) is not currently supported or has a bug:

https://github.com/spring-projects/spring-framework/blob/master/spring-webflux/src/test/java/org/springframework/web/reactive/function/client/WebClientIntegrationTests.java#L149

Bug filed: https://jira.spring.io/browse/SPR-16715

Answer 1

目前 Spring Data REST 和 Spring HATEOAS 都不支持 Reactor 类型。