Question

我尝试将我的Resteasy REST客户端（3.0.8）切换为使用代理机制，因为这看起来对我很好。我可以成功触发REST请求，但现在我需要映射/反序列化响应。代码如下：

RestRequest.java：

ResteasyClient client = new ResteasyClientBuilder().build();
ResteasyWebTarget target = client.target("http://127.0.0.1:8080/backend-1.0-SNAPSHOT/");
CategoryClient categoryClient = target.proxy(CategoryClient.class);
categoryList = categoryClient.getCategories();

CategoryClient.java（代理接口）：

public interface CategoryClient {
    @GET
    @Path("categories")
    @JsonProperty("categories")
    @JsonIgnoreProperties(ignoreUnknown = true)
    @Produces(MediaType.APPLICATION_JSON)
    public List<Category> getCategories();

Category.java（目标模型）：

public class Category {
    private Long id;
    private String name;
    private List<Asset> assetList;
    // getter & setters
}

JSON回复我得到并需要映射：

{
  "_links" : {
    "self" : {
      "href" : "http://127.0.0.1:8080/backend-1.0-SNAPSHOT/categories{?page,size,sort}",
      "templated" : true
    },
    "search" : {
      "href" : "http://127.0.0.1:8080/backend-1.0-SNAPSHOT/categories/search"
    }
  },
  "_embedded" : {
    "categories" : [ {
      "name" : "monkeys",
      "_links" : {
        "self" : {
          "href" : "http://127.0.0.1:8080/backend-1.0-SNAPSHOT/categories/0"
        },
        "assetList" : {
          "href" : "http://127.0.0.1:8080/backend-1.0-SNAPSHOT/categories/0/assetList"
        }
      }
    }, {
      "name" : "donkeys",
      "_links" : {
        "self" : {
          "href" : "http://127.0.0.1:8080/backend-1.0-SNAPSHOT/categories/1"
        },
        "assetList" : {
          "href" : "http://127.0.0.1:8080/backend-1.0-SNAPSHOT/categories/1/assetList"
        }
      }
    }
    ]
  },
  "page" : {
    "size" : 20,
    "totalElements" : 5,
    "totalPages" : 1,
    "number" : 0
  }
}

现在我需要一种机制来将响应映射到List<Category>，目前只提供

javax.ws.rs.client.ResponseProcessingException: javax.ws.rs.ProcessingException:
com.fasterxml.jackson.databind.JsonMappingException: Can not deserialize instance of 
java.util.ArrayList out of START_OBJECT token

我需要采取哪些步骤才能使映射工作？

Answer 1

杰克逊注释仅在应用于您反序列化的类时才有效。实现目标的最简单方法是创建一个表示响应结构的类层次结构：

@JsonIgnoreProperties(ignoreUnknown = true)
class Response {
    private Embedded embedded;
    // getters and setters here
}

@JsonIgnoreProperties(ignoreUnknown = true)
class Embedded {
    private List<Category> categories;
    // getters and setters here
}

@JsonIgnoreProperties(ignoreUnknown = true)
class Category {
    private String name;
    // getters and setters here
}

然后您就可以获得类别名称了。我也在寻找转换选项，但似乎不可能。我发现可能的最好的事情是使用@JsonDeserialize注释重构您的响应：

@JsonDeserialize(converter = ResponseConverter.class)
class Response {
    private List<String> categories;
    // getters and setters
}

class ResponseConverter implements Converter<Map<String, ?>, Response> {
    Response convert(Map<String, ?> jsonInput) {
        // convert jsonInput to response and return
    }
    // implement getInputType and getOutputType methods here
}

Resteasy代理杰克逊映射/反序列化

1 个答案: