JOLT移位转换：收集所有关卡中的所有物品，而不知道有多少个关卡

Question

我正在尝试使用 Jolt 转换来转换 JSON，在这里寻找一些输入。我正在尝试将所有级别中的所有项目放入一个数组中。

我的目标是获得一个包含所有项目的数组，而不知道我在json中有多少个级别。

这是我的输入和预期输出：

如果我有三个等级:

输入：

{
  "id": 11,
  "item": [
    {
      "id": "11_1",
      "item": [
        {
          "id": "11_1_1",
          "item": [
            {
              "id": "11_1_1_1"
            }
          ]
        },
        {
          "id": "11_1_2",
          "item": [
            {
              "id": "11_1_2_1"
            }
          ]
        }
      ]
    }
  ]
}

预期产出:

[
  {
    "id": "11_1"
  },
  {
    "id": "11_1_1"
  },
    {
    "id": "11_1_1_1"
  },
  {
    "id": "11_1_2"
  },
    {
    "id": "11_1_2_1"
  }
]

如果我有两个级别:

输入：

{
  "id": 11,
  "item": [
    {
      "id": "11_1",
      "item": [
        {
          "id": "11_1_1"
        },
        {
          "id": "11_1_2"
        }
      ]
    }
  ]
}

预期产出:

[
  {
    "id": "11_1"
  },
  {
    "id": "11_1_1"
  },
  {
    "id": "11_1_2"
  }
]

我试着写下这样的话:

[
  {
    "operation": "shift",
    "spec": {
      "item": {   //to cover the second level
        "*": "item"
      }
    }
    },
  {
    "operation": "shift",
    "spec": {
      "item": {
        "*": {    //to cover the 3td level
          "item": {
            "*": "item"
          }
        }
      }
    }
    }
]

结果为空，如果我单独运行每个转换，我会在适用时得到结果。你能帮我写一个简单的规范吗？

Answer 1

使用库乔森无限水平的解决方案。

https://github.com/octomix/josson

反序列化

Josson josson = Josson.fromJsonString(
    "{" +
    "  \"id\": 11," +
    "  \"item\": [" +
    "    {" +
    "      \"id\": \"11_1\"," +
    "      \"quantity\": 1," +
    "      \"action\": \"add\"," +
    "      \"state\": \"x\"," +
    "      \"item\": [" +
    "        {" +
    "          \"id\": \"11_1_1\"," +
    "          \"quantity\": 2," +
    "          \"action\": \"drop\"," +
    "          \"state\": \"y\"" +
    "        }," +
    "        {" +
    "          \"id\": \"11_1_2\"," +
    "          \"quantity\": 3," +
    "          \"action\": \"modify\"," +
    "          \"state\": \"z\"" +
    "        }" +
    "      ]" +
    "    }" +
    "  ]" +
    "}");

转型

JsonNode node = josson.getNode("item.cumulateCollect(field(item:), item)");
System.out.println(node.toPrettyString());

语句字段（项：） 从当前对象中删除字段项。
cumulateCollect（） 的第二个参数表示下一个级别。在本例中为项目。

输出

[ {
  "id" : "11_1",
  "quantity" : 1,
  "action" : "add",
  "state" : "x"
}, {
  "id" : "11_1_1",
  "quantity" : 2,
  "action" : "drop",
  "state" : "y"
}, {
  "id" : "11_1_2",
  "quantity" : 3,
  "action" : "modify",
  "state" : "z"
} ]

Answer 2

如果输入像您的情况一样最多有3个级别，则使用此规范

[
  {
    "operation": "shift",
    "spec": {
      "item": {
        "*": {
          "id": "&",
          "item": {
            "*": {
              "id": "&",
              "item": {
                "*": {
                  "id": "&"
                }
              }
            }
          }
        }
      }
    }
  },
  {
    "operation": "shift",
    "spec": {
      "id": {
        "*": "[#1].&1"
      }
    }
  }
]

以便仅使用这一个来处理两种情况。如果还需要一个级别，则添加

,
"item": {
  "*": {
    "id": "&"
  }
}

就在最里面

"id": "&"

编辑:如果您有一些不同于< code>id的其他属性，就像下面的输入示例中那样

{
  "id": 11,
  "item": [
    {
      "id": "11_1",
      "quantity": 1,
      "action": "add",
      "state": "x",
      "item": [
        {
          "id": "11_1_1",
          "quantity": 2,
          "action": "drop",
          "state": "y"
        },
        {
          "id": "11_1_2",
          "quantity": 3,
          "action": "modify",
          "state": "z"
        }
      ]
    }
  ]
}

而不仅仅是一点点修改就可以处理您的新案例：

[
  {
    "operation": "shift",
    "spec": {
      "item": {
        "*": {
          "*": "&",
          "item": {
            "*": {
              "*": "&",
              "item": {
                "*": {
                  "*": "&"
                }
              }
            }
          }
        }
      }
    }
  },
  {
    "operation": "shift",
    "spec": {
      "*": {
        "*": "[#1].&1"
      }
    }
  }
]

这将产生：

[
  {
    "id": "11_1",
    "quantity": 1,
    "action": "add",
    "state": "x"
  },
  {
    "id": "11_1_1",
    "quantity": 2,
    "action": "drop",
    "state": "y"
  },
  {
    "id": "11_1_2",
    "quantity": 3,
    "action": "modify",
    "state": "z"
  }
]