REST Assured 73 - How To Ignore Node/S For JSON Comparison In JSONassert

REST Assured 系列汇总 之 REST Assured 73 - How To Ignore Node/S For JSON Comparison In JSONassert

介绍

我们有时不需要比较 JSON 文档里的所有节点，比较时需忽略一些不匹配的结点。一个现实的例子就是一个时间戳字段，它是变化的，在比较时我们必须忽略这些变化的字段。

前提条件

添加 JSONassert 依赖

<!-- https://mvnrepository.com/artifact/org.skyscreamer/jsonassert -->
<dependency>
    <groupId>org.skyscreamer</groupId>
    <artifactId>jsonassert</artifactId>
    <version>1.5.0</version>
    <scope>test</scope>
</dependency>

请先阅读下面文章，了解 JSONassert Java library 基本概念 ，不同的比较模式和断言 JSON Objects 和 Array。

Introduction To JsonAssert Library

Compare JSON Objects Using JSONassert Library

Compare JSON Arrays Using JSONassert Library

比较时怎么忽略 JSON 中的字段

没有直接的方法去忽略某些字段和属性，我们需要用到 CustomComparator。

 JSONComparator com = new CustomComparator(JSONCompareMode.LENIENT, 
 new Customization("salary", (o1, o2) -> true));

CustomComparator 是一个类，它间接实现 JSONComparator。 Customization 是另外一个类，CustomComparator 的构造函数接收 JSONCompareMode 和一个 Customization 类型的数组。Customization 类的构造函数接收一个包含 euqal() 方法的 ValueMatcher 接口的引用，

// Constructor of CustomComparator
public CustomComparator(JSONCompareMode mode,  Customization... customizations) {
    
    
        super(mode);
        this.customizations = Arrays.asList(customizations);
    }

为了忽略某些字段，跟 JSONassert是没有啥关系的，而是显示地让这些忽略的字段断言 PASS。如果我们从第一个 JSON 文档中获取的值为 v1， 第二个 JSON 文档中的值为 v2，v1 可以等于 或 不等于 v2. 我们就像弄了一个代理，显示地将 v1 和 v2 是相等的，或者说是匹配成功的。

上面的代码中，“salary” 是一个 JSON path，“o1” 和 “o2” 分别是从 JSON 文档中获取的值。无条件使得这两个值是相等的，返回 true。

也可以传多个 Customization 引用，因为 CustomComparator 接收的是 Customization 类型的数组。

 JSONComparator com = new CustomComparator(JSONCompareMode.LENIENT, 
 new Customization("salary", (o1, o2) -> true),
 new Customization("age", (o1, o2) -> true)); 

JSONAssert 类的重载方法 assertEquals() 接收 JSONComparator 引用参数。

忽略简单 JSON object 的字段

JSON String 1

{
    
    
  "id": 1,
  "first_name": "Amod",
  "last_name": "Mahajan",
  "married": false,
  "salary": 123.45
} 

JSON String 2

{
    
    
  "id": 1,
  "first_name": "Amod",
  "last_name": "Mahajan",
  "married": false,
  "salary": 125.45
}

比较时，忽略 “salary” 字段

import org.json.JSONException;
import org.skyscreamer.jsonassert.Customization;
import org.skyscreamer.jsonassert.JSONAssert;
import org.skyscreamer.jsonassert.JSONCompareMode;
import org.skyscreamer.jsonassert.comparator.CustomComparator;
import org.skyscreamer.jsonassert.comparator.JSONComparator;
 
public class IgnoringFieldsFromSimpleJsonObjects {
    
    
 
 public static void main(String[] args) throws JSONException {
    
    
 
 String s1 = "{\r\n" + 
 "  \"id\": 1,\r\n" + 
 "  \"first_name\": \"Amod\",\r\n" + 
 "  \"last_name\": \"Mahajan\",\r\n" + 
 "  \"married\": false,\r\n" + 
 "  \"salary\": 123.45\r\n" + 
 "}";
 
 String s2 = "{\r\n" + 
 "  \"id\": 1,\r\n" + 
 "  \"first_name\": \"Amod\",\r\n" + 
 "  \"last_name\": \"Mahajan\",\r\n" + 
 "  \"married\": false,\r\n" + 
 "  \"salary\": 125.45\r\n" + 
 "}";
 
 JSONComparator com = new CustomComparator(JSONCompareMode.LENIENT, 
 new Customization("salary", (o1, o2) -> true));
 
 JSONAssert.assertEquals(s1, s2, com);
 
 }
 
}

忽略嵌套的 JSON Object 的字段

JSON Object 1

 {
    
    
  "id": 1,
  "first_name": "Amod",
  "last_name": "Mahajan",
  "married": false,
  "salary": 123.45,
  "address":{
    
    
    "permanent" : "KA",
    "city": "Bengaluru"
  }
}

JSON Object 2

{
    
    
  "id": 1,
  "first_name": "Amod",
  "last_name": "Mahajan",
  "married": false,
  "salary": 123.45,
  "address":{
    
    
    "permanent" : "KA",
    "city": "Katihar"
  }
}

比较时忽略 “address” 字段里面的 “city” 结点。我们需要提供忽略字段正确的 JSON path， “address.city“。

import org.json.JSONException;
import org.skyscreamer.jsonassert.Customization;
import org.skyscreamer.jsonassert.JSONAssert;
import org.skyscreamer.jsonassert.JSONCompareMode;
import org.skyscreamer.jsonassert.comparator.CustomComparator;
import org.skyscreamer.jsonassert.comparator.JSONComparator;
 
public class IgnoringFieldsFromNestedJsonObjects {
    
    
 
 public static void main(String[] args) throws JSONException {
    
    
 
 String s1 = "{\r\n" + 
 "  \"id\": 1,\r\n" + 
 "  \"first_name\": \"Amod\",\r\n" + 
 "  \"last_name\": \"Mahajan\",\r\n" + 
 "  \"married\": false,\r\n" + 
 "  \"salary\": 123.45,\r\n" + 
 "  \"address\":{\r\n" + 
 "    \"permanent\" : \"KA\",\r\n" + 
 "    \"city\": \"Bengaluru\"\r\n" + 
 "  }\r\n" + 
 "}";
 
 String s2 = "{\r\n" + 
 "  \"id\": 1,\r\n" + 
 "  \"first_name\": \"Amod\",\r\n" + 
 "  \"last_name\": \"Mahajan\",\r\n" + 
 "  \"married\": false,\r\n" + 
 "  \"salary\": 123.45,\r\n" + 
 "  \"address\":{\r\n" + 
 "    \"permanent\" : \"KA\",\r\n" + 
 "    \"city\": \"Katihar\"\r\n" + 
 "  }\r\n" + 
 "}";
 
 JSONComparator com = new CustomComparator(JSONCompareMode.LENIENT, 
 new Customization("address.city", (o1, o2) -> true));
 
 JSONAssert.assertEquals(s1, s2, com);
 
 }
} 

忽略简单 JSON Array 中的字段

JSON Array 1

[{
    
    
  "id": 1,
  "first_name": "Amod",
  "last_name": "Mahajan",
  "married": false,
  "salary": 123.45
},
{
    
    
  "id": 2,
  "first_name": "Animesh",
  "last_name": "Prashant",
  "married": true,
  "salary": 223.45
}]

JSON Array 2

[{
    
    
  "id": 10,
  "first_name": "Amod",
  "last_name": "Mahajan",
  "married": false,
  "salary": 123.45
},
{
    
    
  "id": 2,
  "first_name": "Animesh",
  "last_name": "Prashant",
  "married": true,
  "salary": 223.45
}]

建设我们不想比较数组中第一个 JSON Object 的 ”id“ 字段。我们需要忽略的 JSON path 就是 “[0].id”，但是如果我们选择的是 LENIENT mode，字段是不会忽略的。针对特定索引的元素，我们应该用 STRICT mode。

import org.json.JSONException;
import org.skyscreamer.jsonassert.Customization;
import org.skyscreamer.jsonassert.JSONAssert;
import org.skyscreamer.jsonassert.JSONCompareMode;
import org.skyscreamer.jsonassert.comparator.CustomComparator;
import org.skyscreamer.jsonassert.comparator.JSONComparator;
 
public class IgnoringFieldsFromSimpleJsonArray {
    
    
 
 public static void main(String[] args) throws JSONException {
    
    
 
 String s1 = "[{\r\n" + 
 "  \"id\": 1,\r\n" + 
 "  \"first_name\": \"Amod\",\r\n" + 
 "  \"last_name\": \"Mahajan\",\r\n" + 
 "  \"married\": false,\r\n" + 
 "  \"salary\": 123.45\r\n" + 
 "},\r\n" + 
 "{\r\n" + 
 "  \"id\": 2,\r\n" + 
 "  \"first_name\": \"Animesh\",\r\n" + 
 "  \"last_name\": \"Prashant\",\r\n" + 
 "  \"married\": true,\r\n" + 
 "  \"salary\": 223.45\r\n" + 
 "}]";
 
 String s2 = "[{\r\n" + 
 "  \"id\": 10,\r\n" +       
 "  \"first_name\": \"Amod\",\r\n" + 
 "  \"last_name\": \"Mahajan\",\r\n" + 
 "  \"married\": false,\r\n" + 
 "  \"salary\": 123.45\r\n" + 
 "},\r\n" + 
 "{\r\n" + 
 "  \"id\": 2,\r\n" + 
 "  \"first_name\": \"Animesh\",\r\n" + 
 "  \"last_name\": \"Prashant\",\r\n" + 
 "  \"married\": true,\r\n" + 
 "  \"salary\": 223.45\r\n" + 
 "}]";
 
 JSONComparator com = new CustomComparator(JSONCompareMode.STRICT, 
 
 new Customization("[0].id", (o1, o2) -> true));
 
 JSONAssert.assertEquals(s1, s2, com);
 
 }
 
} 

如果我们想忽略所有索引元素，我们可以传递 “[*].id“ JSON path，就可以用 STRICT 或 LENIENT mode 了。

忽略嵌套的 JSON Array 中的字段

JSON Array 1

[
  {
    
    
    "id": 1,
    "first_name": "Amod",
    "last_name": "Mahajan",
    "married": false,
    "salary": 123.45,
    "mob": [
      {
    
    
        "type": "personal",
        "number": "1234566"
      },
      {
    
    
        "type": "business",
        "number": "987654321"
      }
    ]
  },
  {
    
    
    "id": 2,
    "first_name": "Animesh",
    "last_name": "Prashant",
    "married": true,
    "salary": 223.45,
    "mob": [
      {
    
    
        "type": "personal",
        "number": "1234566"
      },
      {
    
    
        "type": "business",
        "number": "987654321"
      }
    ]
  }
]

JSON Array 2

[
  {
    
    
    "id": 1,
    "first_name": "Amod",
    "last_name": "Mahajan",
    "married": false,
    "salary": 123.45,
    "mob": [
      {
    
    
        "type": "personal",
        "number": "1234566"
      },
      {
    
    
        "type": "business",
        "number": "34545646"
      }
    ]
  },
  {
    
    
    "id": 2,
    "first_name": "Animesh",
    "last_name": "Prashant",
    "married": true,
    "salary": 223.45,
    "mob": [
      {
    
    
        "type": "personal",
        "number": "1234566"
      },
      {
    
    
        "type": "business",
        "number": "987654321"
      }
    ]
  }
]

假设想忽略第一个索引元素中第二个 mobile 中的 ”number“ 字段，那么 json path 就是 “[0].mob[1].number“

import org.json.JSONException;
import org.skyscreamer.jsonassert.Customization;
import org.skyscreamer.jsonassert.JSONAssert;
import org.skyscreamer.jsonassert.JSONCompareMode;
import org.skyscreamer.jsonassert.comparator.CustomComparator;
import org.skyscreamer.jsonassert.comparator.JSONComparator;
 
public class IgnoringFieldsFromNestedJsonArray {
    
    
 
 public static void main(String[] args) throws JSONException {
    
    
 
 String s1 = "[\r\n" + 
 "  {\r\n" + 
 "    \"id\": 1,\r\n" + 
 "    \"first_name\": \"Amod\",\r\n" + 
 "    \"last_name\": \"Mahajan\",\r\n" + 
 "    \"married\": false,\r\n" + 
 "    \"salary\": 123.45,\r\n" + 
 "    \"mob\": [\r\n" + 
 "      {\r\n" + 
 "        \"type\": \"personal\",\r\n" + 
 "        \"number\": \"1234566\"\r\n" + 
 "      },\r\n" + 
 "      {\r\n" + 
 "        \"type\": \"business\",\r\n" + 
 "        \"number\": \"987654321\"\r\n" + 
 "      }\r\n" + 
 "    ]\r\n" + 
 "  },\r\n" + 
 "  {\r\n" + 
 "    \"id\": 2,\r\n" + 
 "    \"first_name\": \"Animesh\",\r\n" + 
 "    \"last_name\": \"Prashant\",\r\n" + 
 "    \"married\": true,\r\n" + 
 "    \"salary\": 223.45,\r\n" + 
 "    \"mob\": [\r\n" + 
 "      {\r\n" + 
 "        \"type\": \"personal\",\r\n" + 
 "        \"number\": \"1234566\"\r\n" + 
 "      },\r\n" + 
 "      {\r\n" + 
 "        \"type\": \"business\",\r\n" + 
 "        \"number\": \"987654321\"\r\n" + 
 "      }\r\n" + 
 "    ]\r\n" + 
 "  }\r\n" + 
 "]";
 
 String s2 = "[\r\n" + 
 "  {\r\n" + 
 "    \"id\": 1,\r\n" + 
 "    \"first_name\": \"Amod\",\r\n" + 
 "    \"last_name\": \"Mahajan\",\r\n" + 
 "    \"married\": false,\r\n" + 
 "    \"salary\": 123.45,\r\n" + 
 "    \"mob\": [\r\n" + 
 "      {\r\n" + 
 "        \"type\": \"personal\",\r\n" + 
 "        \"number\": \"1234566\"\r\n" + 
 "      },\r\n" + 
 "      {\r\n" + 
 "        \"type\": \"business\",\r\n" + 
 "        \"number\": \"34545646\"\r\n" + 
 "      }\r\n" + 
 "    ]\r\n" + 
 "  },\r\n" + 
 "  {\r\n" + 
 "    \"id\": 2,\r\n" + 
 "    \"first_name\": \"Animesh\",\r\n" + 
 "    \"last_name\": \"Prashant\",\r\n" + 
 "    \"married\": true,\r\n" + 
 "    \"salary\": 223.45,\r\n" + 
 "    \"mob\": [\r\n" + 
 "      {\r\n" + 
 "        \"type\": \"personal\",\r\n" + 
 "        \"number\": \"1234566\"\r\n" + 
 "      },\r\n" + 
 "      {\r\n" + 
 "        \"type\": \"business\",\r\n" + 
 "        \"number\": \"987654321\"\r\n" + 
 "      }\r\n" + 
 "    ]\r\n" + 
 "  }\r\n" + 
 "]";
 
 System.out.println(s1);
 System.out.println(s2);
 JSONComparator com = new CustomComparator(JSONCompareMode.STRICT, 
 new Customization("[0].mob[1].number",(o1, o2) -> true));
 
 JSONAssert.assertEquals(s1, s2, com);
 
 }
 
} 

注意，比较时如果忽略的 JSON path 在 JSON 文档中找不到， 测试将会失败。