如何通过JsonPath更直接地从JSON创建Java的GitlabProject对象？

我当前通过以下代码提取JSON数据来构建GitlabProject对象：

List<String> httpList = JsonPath.read(json, "$.*.http_url_to_repo");
List<String> idList = JsonPath.read(json, "$.*.id");

for (int i = 0; i < httpList.size(); i++)
{
    back.add(new GitlabProject(httpList.get(i), idList.get(i)));
}

对应的JSON结构示例：

[
    {
        "id": 63,
        "description": null,
        "name": "conti-maven-plugin-mm",
        "name_with_namespace": "ik / spu / other / conti-maven-plugin-mm",
        "path": "conti-maven-plugin-mm",
        "path_with_namespace": "ik/spu/other/conti-maven-plugin-mm",
        "created_at": "2023-01-30T12:33:59.218Z",
        "default_branch": "main",
        "tag_list": [],
        "topics": [],
        "ssh_url_to_repo": "git@gitlab-test.continentale.loc:ik/spu/other/conti-maven-plugin-mm.git",
        "http_url_to_repo": "https://gitlab-test.continentale.loc/ik/spu/other/conti-maven-plugin-mm.git",
        "web_url": "https://gitlab-test.continentale.loc/ik/spu/other/conti-maven-plugin-mm"
        // 其他字段省略
    }
]

三种更直接的实现方式 #

• 方式1：JsonPath直接映射到对象列表
  先确保GitlabProject类的字段与JSON键对应（或用@JsonProperty注解适配），然后直接读取为对象列表：

  // 配置Jackson作为JsonPath的反序列化器
  Configuration config = Configuration.defaultConfiguration()
      .setProvider(new JacksonJsonProvider());
  
  List<GitlabProject> projectList = JsonPath.using(config)
      .parse(json)
      .read("$", new TypeRef<List<GitlabProject>>() {});
  

  类定义示例（带构造函数注解）：

  public class GitlabProject {
      private String httpUrlToRepo;
      private String id;
  
      @JsonCreator
      public GitlabProject(
          @JsonProperty("http_url_to_repo") String httpUrlToRepo,
          @JsonProperty("id") String id
      ) {
          this.httpUrlToRepo = httpUrlToRepo;
          this.id = id;
      }
  
      // 可选：添加getter方法
  }
  

• 方式2：直接用Jackson反序列化（无需JsonPath）
  如果不需要筛选字段，直接用Jackson的ObjectMapper更简洁：

  ObjectMapper mapper = new ObjectMapper();
  List<GitlabProject> projectList = mapper.readValue(
      json,
      new TypeReference<List<GitlabProject>>() {}
  );
  

• 方式3：JsonPath筛选特定字段后映射
  若只需要id和http_url_to_repo字段，可先筛选再映射：

  List<GitlabProject> projectList = JsonPath.read(
      json,
      "$.*.['id', 'http_url_to_repo']",
      new TypeRef<List<GitlabProject>>() {}
  );
  

内容的提问来源于stack exchange，提问作者JF Meier