一、簡(jiǎn)介

我們先看下面的json數(shù)據(jù)

{ 
  "id": 1, 
  "name": "g2",　 
  "desc":"b2"
 }

假設(shè), 我們要求id為long型, id寝优、name非空条舔。desc可空。如何衡量json數(shù)據(jù)是有效的呢乏矾？現(xiàn)在流行的json schema 是用來校驗(yàn)json數(shù)據(jù)是否合法孟抗。

詳情請(qǐng)移至 https://spacetelescope.github.io/understanding-json-schema/

二、keyWords介紹

1钻心、keyWords速記表

2棺棵、具體使用如下

type關(guān)鍵字
①、type = object, properties關(guān)鍵字是必需的潘悼。
②律秃、type = array, items關(guān)鍵字是必需的。

porperties關(guān)鍵字

{
      type: "object";
      properties: {
        number: { type: "number" };
        name: { type: "string" };
      };
    }

additionalProperties關(guān)鍵字

"additionalProperties": false ：json串只能出現(xiàn)schema定義的屬性治唤。
"additionalProperties": { "type": "string" } ：json串能出現(xiàn)不在schema定義范圍內(nèi)的屬性, 但屬性的類型必須為string

{
      type: "object";
      properties: { number: { type: "number" }; name: { type: "string" } };
      additionalProperties: false;
}

required關(guān)鍵字
"required": ["name"] ： json串必須出現(xiàn)name屬性

{
      type: "object";
      properties: { number: { type: "number" }; name: { type: "string" } };
      additionalProperties: false;
      required: ["name"];
}

dependencies關(guān)鍵字

dependencies": {
    "number": ["name"]
} 

number的出現(xiàn)必須依賴在name的基礎(chǔ)上, 換而言之 , number出現(xiàn),則name必須出現(xiàn);name的出現(xiàn)與number并沒有毛關(guān)系

{
      type: "object";
      properties: { number: { type: "number" }; name: { type: "string" } };
      additionalProperties: false;
      required: ["name"];
      dependencies: { number: ["name"] };
}

patternProperties關(guān)鍵字

"patternProperties": {
   "^S_": { "type": "string" },
   "^I_": { "type": "integer" }
}

以s棒动、I開頭的屬性必須是String類型

{
      type: "object";
      properties: { number: { type: "number" }; name: { type: "string" } };
      additionalProperties: false;
      required: ["name"];
      dependencies: { number: ["name"] };
      patternProperties: {
        "^S_": { type: "string" };
        "^I_": { type: "integer" };
      };
}

enum關(guān)鍵字

{
      type: "string";
      enum: ["red", "amber", "green"];
}

anyOf關(guān)鍵字
anyOf: 對(duì)所有屬性范疇生效。所有屬性字符串長(zhǎng)度最大不能》5

{
  "anyOf": [
    { "type": "string", "maxLength": 5 },
    { "type": "number", "minimum": 0 }
  ]
}

allOf關(guān)鍵字
allOf ： type必須相同宾添。不能即String船惨、又number

{
      allOf: [{ type: "string" }, { maxLength: 5 }];
}

oneOf關(guān)鍵字

{
  "type": "number",
  "oneOf": [
    { "multipleOf": 5 },
    { "multipleOf": 3 }
  ]
}

**not關(guān)鍵字****

{
  "not": {
    "type": "string"
  }
}

$schema關(guān)鍵字

schema ： 聲明json片段是json schema模式, 并不是 普通json串, 同時(shí)也聲明了json schema版本

三、拓展

1缕陕、復(fù)用

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

如果我們想復(fù)用上述的json串, 可以使用definitions關(guān)鍵字粱锐。json結(jié)構(gòu)定義如下 ：

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

如何引用 ？ 可以使用$ref關(guān)鍵字

{ "$ref": "#/definitions/address" }

或者
{ "$ref": "definitions.json#/address" }

例子如下 ：
schema定義

{
  "$schema": "http://json-schema.org/draft-04/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": { "$ref": "#/definitions/address" },
    "shipping_address": { "$ref": "#/definitions/address" }
  }
}

目標(biāo)匹配json數(shù)據(jù)

{
  "shipping_address": {
    "street_address": "1600 Pennsylvania Avenue NW",
    "city": "Washington",
    "state": "DC"
  },
  "billing_address": {
    "street_address": "1st Street SE",
    "city": "Washington",
    "state": "DC"
  }
}

2扛邑、延伸屬性

json schema

{
  "$schema": "http://json-schema.org/draft-04/schema#",
  "definitions": {
    "address": {
      "type": "object",
      "properties": {
        "street_address": { "type": "string" },
        "city":           { "type": "string" },
        "state":          { "type": "string" }
      },
      "required": ["street_address", "city", "state"]
    }
  },
  "type": "object",
  "properties": {
    "billing_address": { "$ref": "#/definitions/address" },
    "shipping_address": {
      "allOf": [
        { "$ref": "#/definitions/address" },
        { "properties":
          { "type": { "enum": [ "residential", "business" ] } },
          "required": ["type"]
        }
      ]
    }
  }
}

可匹配json

{
  "shipping_address": {
    "street_address": "1600 Pennsylvania Avenue NW",
    "city": "Washington",
    "state": "DC",
    "type": "business"
  }
}