Spring Boot中静态方法返回CommonResult为空的原因是什么？

public class commonresult<t> implements serializable {
    public static integer code_success = 0;

    private integer code;
    private string message;
    public t data; // data 的访问权限由 private 改为 public

    public integer getcode() {
        return code;
    }

    public string getmessage() {
        return message;
    }

    public static <k> commonresult<k> success(k input_data) {
        commonresult<k> result = new commonresult<>();
        result.code = code_success;
        result.data = input_data;
        result.message = "";
        return result;
    }
}

@getmapping("/get2")
public commonresult<uservo> get2(@requestparam("id") integer id) {
    uservo user = new uservo().setid(id).setusername(uuid.randomuuid().tostring());
    // 返回结果
    return commonresult.success(user).data; // 使用 commonresult 的公共 data 字段
}

{
  "code": 0,
  "message": "",
  "data": {
    "id": 3,
    "username": "1e29a45d-6363-43b3-a08d-3989ea70d1ae"
  }
}