使用Rest Assured进行JSON Schema验证失败，请求技术协助

问题场景 #

使用Java结合Rest Assured做JSON Schema验证时，抛出Schema to use cannot be null异常，代码及错误信息如下：

原代码 #

public class Response_SchemaValidation 
{
    public static void main(String [] args) throws FileNotFoundException
    {
        System.out.println("This is testing...");
        
        String str ="{\r\n" + 
                "    \"firstname\": \"Sally\",\r\n" + 
                "    \"lastname\": \"Brown\",\r\n" + 
                "    \"totalprice\": 111,\r\n" + 
                "    \"depositpaid\": true,\r\n" + 
                "    \"bookingdates\": {\r\n" + 
                "        \"checkin\": \"2013-02-23\",\r\n" + 
                "        \"checkout\": \"2014-10-23\"\r\n" + 
                "    },\r\n" + 
                "    \"additionalneeds\": \"Breakfast\"\r\n" + 
                "}";
        
        
        //InputStream insp = new FileInputStream("C:\\Users\\ANANDA K R\\eclipse-workspace\\API_Automation_petStore\\Schema_validation_jsonFiles\\Response_SchemaValidation.json");
        //File fl1= new File("C:\\Users\\ANANDA K R\\eclipse-workspace\\API_Automation_petStore\\Schema_validation_jsonFiles\\Response_SchemaValidation.json");
        RequestSpecification reqstBody = 
                RestAssured.given().body(str).header("Content-Type","application/json");
            Response resp = reqstBody.post("https://restful-booker.herokuapp.com/booking");
            //resp.js 
            
            System.out.println(resp.statusCode());
            String str2 = resp.getBody().asString();
            System.out.println("str2 ---"+str2);
            Assert.assertEquals(resp.getBody().asString(), matchesJsonSchemaInClasspath("Response_SchemaValidation.json"));
            
        
    }

}

异常信息 #

Exception in thread "main" java.lang.IllegalArgumentException: Schema to use cannot be null
    at io.restassured.module.jsv.JsonSchemaValidator.validateSchemaIsNotNull(JsonSchemaValidator.java:270)
    at io.restassured.module.jsv.JsonSchemaValidator.access$300(JsonSchemaValidator.java:75)
    at io.restassured.module.jsv.JsonSchemaValidator$JsonSchemaValidatorFactory.create(JsonSchemaValidator.java:281)
    at io.restassured.module.jsv.JsonSchemaValidator.matchesJsonSchema(JsonSchemaValidator.java:166)
    at io.restassured.module.jsv.JsonSchemaValidator.matchesJsonSchemaInClasspath(JsonSchemaValidator.java:117)
    at basic_SchemaValidation.Response_SchemaValidation.main(Response_SchemaValidation.java:173)

原因分析 #

1. Schema文件路径错误：matchesJsonSchemaInClasspath方法仅在**类路径（classpath）**下查找文件，原代码中Schema文件放在项目自定义目录，未加入类路径，导致Rest Assured找不到文件，返回null的Schema。
2. 验证方法用法错误：用Assert.assertEquals将响应字符串与matchesJsonSchemaInClasspath返回的验证器对象直接比较，这是错误的用法，Rest Assured的Schema验证需通过链式断言调用。

解决方案 #

1. 调整Schema文件位置 #

• Maven/Gradle项目：将Response_SchemaValidation.json放到src/main/resources目录下（该目录默认属于类路径）。
• 普通Java项目：将Schema文件所在目录添加到项目的类路径配置中。

2. 修正验证代码 #

使用Rest Assured的链式断言语法执行Schema验证，替换错误的Assert.assertEquals写法：

import io.restassured.RestAssured;
import io.restassured.module.jsv.JsonSchemaValidator;
import static io.restassured.RestAssured.given;

public class Response_SchemaValidation {
    public static void main(String[] args) {
        System.out.println("This is testing...");

        String str = "{\r\n" +
                "    \"firstname\": \"Sally\",\r\n" +
                "    \"lastname\": \"Brown\",\r\n" +
                "    \"totalprice\": 111,\r\n" +
                "    \"depositpaid\": true,\r\n" +
                "    \"bookingdates\": {\r\n" +
                "        \"checkin\": \"2013-02-23\",\r\n" +
                "        \"checkout\": \"2014-10-23\"\r\n" +
                "    },\r\n" +
                "    \"additionalneeds\": \"Breakfast\"\r\n" +
                "}";

        RestAssured.baseURI = "https://restful-booker.herokuapp.com";

        // 发送请求并执行Schema验证
        given()
                .header("Content-Type", "application/json")
                .body(str)
        .when()
                .post("/booking")
        .then()
                .statusCode(200) // 先验证响应状态码
                .assertThat()
                .body(JsonSchemaValidator.matchesJsonSchemaInClasspath("Response_SchemaValidation.json")); // 验证JSON Schema

        System.out.println("JSON Schema验证通过");
    }
}

3. 确保Schema文件内容正确 #

对应restful-booker创建booking的响应，示例Schema文件内容如下：

{
  "$schema": "http://json-schema.org/draft-07/schema#",
  "type": "object",
  "properties": {
    "bookingid": {
      "type": "integer"
    },
    "booking": {
      "type": "object",
      "properties": {
        "firstname": {
          "type": "string"
        },
        "lastname": {
          "type": "string"
        },
        "totalprice": {
          "type": "integer"
        },
        "depositpaid": {
          "type": "boolean"
        },
        "bookingdates": {
          "type": "object",
          "properties": {
            "checkin": {
              "type": "string"
            },
            "checkout": {
              "type": "string"
            }
          },
          "required": ["checkin", "checkout"]
        },
        "additionalneeds": {
          "type": "string"
        }
      },
      "required": ["firstname", "lastname", "totalprice", "depositpaid", "bookingdates"]
    }
  },
  "required": ["bookingid", "booking"]
}

关键注意点 #

• 类路径优先级：如果Schema文件在子目录，路径要写成subdir/Response_SchemaValidation.json，保证matchesJsonSchemaInClasspath能正确定位。
• 依赖检查：确保项目中已引入Rest Assured的JSON Schema验证依赖（Maven需添加io.restassured:json-schema-validator依赖）。

内容的提问来源于stack exchange，提问作者Reddy Anand