如何用Rest-Assured+Java从无标签嵌套列表提取指定键值对

需要从接口返回的嵌套JSON数组中提取索引[1]位置的外层userId和oneAccountId值（层级中存在多个userId键，仅需最外层的）。Postman测试脚本可正常提取并存储为变量，但Rest-Assured+TestNG框架中的当前代码返回null，求正确实现方案。

示例响应体 #

[
    {
        "userId": 4813,
        "oneAccountId": 20785114,
        "userOptions": [
            {
                "userOptionsId": null,
                "userId": null,
            },
            {
                "userOptionsId": null,
                "userId": null,
            },
            {
                "userOptionsId": null,
                "userId": null,
            },
            {
                "userOptionsId": null,
                "userId": null,
            },
            {
                "userOptionsId": 16093,
                "userId": 4813,
            }
        ],
        "accessLocations": null
    },
    {
        "userId": 56725,
        "oneAccountId": 66443583,
        "userOptions": [
            {
                "userOptionsId": null,
                "userId": null,
            },
            {
                "userOptionsId": null,
                "userId": null,
            },
            {
                "userOptionsId": null,
                "userId": null,
            },
            {
                "userOptionsId": 27135,
                "userId": 56725,
            },
            {
                "userOptionsId": 27145,
                "userId": 56725,
            }
        ],
        "accessLocations": null
    },
    {
        "userId": 21455,
        "oneAccountId": 35993484,
        "userOptions": [
            {
                "userOptionsId": 29253,
                "userId": 21455,
            },
            {
                "userOptionsId": null,
                "userId": null,
            },
            {
                "userOptionsId": 29023,
                "userId": 21455,
            },
            {
                "userOptionsId": 3843,
                "userId": 21455,
            },
            {
                "userOptionsId": 3615,
                "userId": 21455,
            }
        ],
        "accessLocations": null
    },
    {
        "userId": 52903,
        "oneAccountId": 61477703,
        "userOptions": [
            {
                "userOptionsId": null,
                "userId": null
            },
            {
                "userOptionsId": null,
                "userId": null,
            },
            {
                "userOptionsId": null,
                "userId": null,
            },
            {
                "userOptionsId": 24303,
                "userId": 52903,
            },
            {
                "userOptionsId": 24313,
                "userId": 52903,
            }
        ],
        "accessLocations": null
    }
]

Postman可用代码 #

const response = JSON.parse(responseBody);
pm.environment.set("userId", response[1].userId);
pm.environment.set("oneAccountId", response[1].oneAccountId);

当前Rest-Assured错误代码 #

@Test (dataProvider = "endPoints")
public void get_users_associated_to_a_particular_compcode(String endPoints) 
{
    Response response = given().
                    header("Content-Type", "application/json").
                    header("Authorization", "Bearer " + accessToken).
                    get(endPoints).
                    then().
                    statusCode(200).
                    contentType(ContentType.JSON).
                    extract().response();
   JsonPath extractValue = response.jsonPath();
   String userID = extractValue.getList("userId").get(1).toString();
   String oneAccountID = extractValue.getList("oneAccountId").get(1).toString();
}

错误原因 #

原代码中extractValue.getList("userId")会递归遍历整个JSON结构，收集所有名为userId的字段值（包括嵌套在userOptions数组里的userId），因此get(1)拿到的并不是外层数组索引1的对象的userId，导致结果不符合预期甚至返回null。

正确实现方案 #

方案1：直接通过JsonPath索引定位（推荐） #

利用JsonPath语法直接定位到外层数组的第1个元素，再提取对应的字段：

@Test (dataProvider = "endPoints")
public void get_users_associated_to_a_particular_compcode(String endPoints) 
{
    Response response = given()
                    .header("Content-Type", "application/json")
                    .header("Authorization", "Bearer " + accessToken)
                    .get(endPoints)
                    .then()
                    .statusCode(200)
                    .contentType(ContentType.JSON)
                    .extract()
                    .response();
                    
    JsonPath extractValue = response.jsonPath();
    // 直接定位到外层数组索引1的对象，提取指定字段
    Integer userId = extractValue.get("[1].userId");
    Integer oneAccountId = extractValue.get("[1].oneAccountId");
    
    // 如需转成String类型
    String userIdStr = String.valueOf(userId);
    String oneAccountIdStr = String.valueOf(oneAccountId);
}

方案2：先获取整个数组再提取对象字段 #

先把外层数组转为List对象，再取指定索引的元素，最后提取字段：

@Test (dataProvider = "endPoints")
public void get_users_associated_to_a_particular_compcode(String endPoints) 
{
    Response response = given()
                    .header("Content-Type", "application/json")
                    .header("Authorization", "Bearer " + accessToken)
                    .get(endPoints)
                    .then()
                    .statusCode(200)
                    .contentType(ContentType.JSON)
                    .extract()
                    .response();
                    
    JsonPath extractValue = response.jsonPath();
    // 获取外层整个用户对象数组
    List<Map<String, Object>> userList = extractValue.getList("$");
    // 取出索引1的用户对象
    Map<String, Object> targetUser = userList.get(1);
    
    // 提取外层字段
    Integer userId = (Integer) targetUser.get("userId");
    Integer oneAccountId = (Integer) targetUser.get("oneAccountId");
    
    // 如需转成String类型
    String userIdStr = userId.toString();
    String oneAccountIdStr = oneAccountId.toString();
}

内容的提问来源于stack exchange，提问作者Jimil Patel