重用

重用此架构，因此习惯上（但不是必需）将其放在父架构下的 ：definitions
{
  "definitions": {
    "address": {
      "type": "object",
      "properties": {
        "street_address": { "type": "string" },
        "city":           { "type": "string" },
        "state":          { "type": "string" }
      },
      "required": ["street_address", "city", "state"]
    }
  }
}
{ "$ref": "#/definitions/address" }
  1. 转到文档的根目录
  1. 找到钥匙的价值 "definitions"
  1. 在该对象中，找到键的值 "address"

递归

$ref元素可用于创建引用自己的递归模式
{
  "$schema": "http://json-schema.org/draft-07/schema#",

  "definitions": {
    "person": {
      "type": "object",
      "properties": {
        "name": { "type": "string" },
        "children": {
          "type": "array",
          "items": { "$ref": "#/definitions/person" },
          "default": []
        }
      }
    }
  },

  "type": "object",

  "properties": {
    "person": { "$ref": "#/definitions/person" }
  }
}
相互$ref引用的架构循环可能会在解析器中引起无限循环，因此明确不允许这样做
// error
{
  "definitions": {
    "alice": {
      "anyOf": [
        { "$ref": "#/definitions/bob" }
      ]
    },
    "bob": {
      "anyOf": [
        { "$ref": "#/definitions/alice" }
      ]
    }
  }
}

$id & $ref

{
  "$schema": "http://json-schema.org/draft-07/schema#",

  "definitions": {
    "address": {
      "$id": "#address",
      "type": "object",
      "properties": {
        "street_address": { "type": "string" },
        "city":           { "type": "string" },
        "state":          { "type": "string" }
      },
      "required": ["street_address", "city", "state"]
    }
  },

  "type": "object",

  "properties": {
    "billing_address": { "$ref": "#address" },
    "shipping_address": { "$ref": "#address" }
  }
}

$ref & Combining schemas

{
  "$schema": "http://json-schema.org/draft-06/schema#",

  "definitions": {
    "address": {
      "type": "object",
      "properties": {
        "street_address": { "type": "string" },
        "city":           { "type": "string" },
        "state":          { "type": "string" }
      },
      "required": ["street_address", "city", "state"]
    }
  },

  "type": "object",

  "properties": {
    "billing_address": { "$ref": "#/definitions/address" },
    "shipping_address": {
      "allOf": [
        { "$ref": "#/definitions/address" },
        { "properties":
          { "type": { "enum": [ "residential", "business" ] } },
          "required": ["type"]
        }
      ]
    }
  }
}
badge