使用Jolt转换含子数组的JSON为带父属性的父元素数组

需求 #

将包含多层子数组的JSON转换为数组，每个数组元素对应原JSON中的一个Employee对象，同时完整保留其所属的Transmission和Employer层级属性。

输入JSON #

{
    "Transmission": {
        "TransmissionGUID": "transId1",
        "Employer": [
            {
                "EmployerPartyID": "employerId1",
                "Employee": [
                    {
                        "EmployeeGenderCode": "M",
                        "MaritalStatusCode": "Married"
                    },
                    {
                        "EmployeeGenderCode": "F",
                        "MaritalStatusCode": "UnMarried"
                    }
                ]
            },
            {
                "EmployerPartyID": "employerId2",
                "Employee": [
                    {
                        "EmployeeGenderCode": "M2",
                        "MaritalStatusCode": "Married2"
                    },
                    {
                        "EmployeeGenderCode": "F2",
                        "MaritalStatusCode": "UnMarried"
                    }
                ]
            }
        ]
    }
}

期望输出JSON #

[
    {
        "Transmission": {
            "TransmissionGUID": "transId1",
            "Employer": [
                {
                    "EmployerPartyID": "employerId1",
                    "Employee": [
                        {
                            "EmployeeGenderCode": "M",
                            "MaritalStatusCode": "Married"
                        }
                    ]
                }
            ]
        }
    },
    {
        "Transmission": {
            "TransmissionGUID": "transId1",
            "Employer": [
                {
                    "EmployerPartyID": "employerId1",
                    "Employee": [
                        {
                            "EmployeeGenderCode": "F",
                            "MaritalStatusCode": "UnMarried"
                        }
                    ]
                }
            ]
        }
    },
    {
        "Transmission": {
            "TransmissionGUID": "transId1",
            "Employer": [
                {
                    "EmployerPartyID": "employerId2",
                    "Employee": [
                        {
                            "EmployeeGenderCode": "M2",
                            "MaritalStatusCode": "Married2"
                        }
                    ]
                }
            ]
        }
    },
    {
        "Transmission": {
            "TransmissionGUID": "transId1",
            "Employer": [
                {
                    "EmployerPartyID": "employerId2",
                    "Employee": [
                        {
                            "EmployeeGenderCode": "F2",
                            "MaritalStatusCode": "UnMarried"
                        }
                    ]
                }
            ]
        }
    }
]

尝试的Jolt Spec（无效） #

[
    {
      "operation": "shift",
      "spec": {
        "Transmission": {
          "Employer": {
            "*": {
              "Employee": {
                "*": {
                    "@(4,TransmissionGUID)": "[].Transmission.TransmissionGUID",
                    "@(2,EmployerPartyID)": "[].Transmission.Employer[].EmployerPartyID",
                  "@": "[].Transmission.Employer[].Employee[]"
                }
              }
            }
          }
        }
      }
    }
]

问题分析 #

原Spec的核心问题是使用[]作为数组索引时，会将所有属性追加到同一个数组元素中，无法为每个Employee生成独立的对象条目；同时Employee[]会将多个员工对象塞到同一个数组里，不符合期望输出的单元素数组结构。

修正后的Jolt Spec #

[
  {
    "operation": "shift",
    "spec": {
      "Transmission": {
        // 临时存储顶层TransmissionGUID
        "TransmissionGUID": "temp_trans_guid",
        "Employer": {
          "*": {
            // 按Employer索引存储对应的EmployerPartyID
            "EmployerPartyID": "temp_employer_id[&1]",
            "Employee": {
              "*": {
                // 用Employer索引(&3)和Employee索引(&1)组合生成唯一数组键，确保每个Employee对应独立条目
                "@(4,temp_trans_guid)": "[&3_&1].Transmission.TransmissionGUID",
                "@(2,temp_employer_id[&3])": "[&3_&1].Transmission.Employer[0].EmployerPartyID",
                // 将当前Employee对象放入单元素数组
                "@": "[&3_&1].Transmission.Employer[0].Employee[0]"
              }
            }
          }
        }
      }
    }
  },
  // 清理临时变量
  {
    "operation": "remove",
    "spec": {
      "temp_trans_guid": "",
      "temp_employer_id": ""
    }
  }
]

说明 #

1. 临时存储：先把顶层的TransmissionGUID和每个Employer的EmployerPartyID存入临时变量，方便后续引用。
2. 唯一索引：通过&3_&1（&3是当前Employer的数组索引，&1是当前Employee的数组索引）生成唯一的数组键，确保每个Employee对应一个独立的输出对象。
3. 单元素数组：将Employer和Employee都处理为单元素数组，完全匹配期望输出的结构。

内容的提问来源于stack exchange，提问作者tys