Jmeter之Json提取器详解（史上最全）

参考资料：https://www.bbsmax.com/A/D854lmBw5E/

Jsonpath在线测试：http://jsonpath.com/

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实际工作中用到的一些场景：

1. 提取某个特定的值
2. 提取多个值
3. 按条件取值
4. 阵列取值（返回所有元素的列表/数组）
5. 提取多个值

Jsonpath提取器需要另外安装

• 下载plugins-manager.jar加入其加入JMETER_HOME/lib/ext目录，
• 重新启动JMeter，
• 点击Options > Plugins Manager顶部菜单，
• 选择Available Plugins标签，
• 选择Json Plugins并双击应用更改并重新启动JMeter。

使用方法：

Json Path提取器应放在HTTP Sampler下。可设置的参数有：

• 变量名称：分号单独的变量名称，
• JSON Path Expressions：从json响应中提取内容的表达式，
• 匹配数字：-1对于所有，0对于随机的，n对于第n个，
• Compute concatenation var：创建一个${foo_ALL}包含所有提取值的串联的变量，
• 默认值：如果表达式不适用于正在处理的json文档，使用此处给定的默认值。

接下来用一个实际案例来演示Json提取的一些用法：

示例：有如下json

{
    "code": 0,
    "data": {
        "total": 10,
        "pageNo": 1,
        "pageSize": 100,
        "items": [
            {
                "friendHeadLogoUrl": null,
                "msg": "你好，我仰慕你的才华！",
                "shield": 0,
                "star": 0,
                "friendNickname": "Auto",
                "origin": 202,
                "black": 0,
                "memo": null,
                "updateTime": 1591169560056,
                "type": 2,
                "userId": 1268082752079560705,
                "friendId": 1267735865761759234,
                "createTime": 1591169490879,
                "blackUpdateTime": 0,
                "addUpdateTime": 1591169560056,
                "id": 1268082870707040258,
                "close": 0,
                "status": 2
            },
            {
                "friendHeadLogoUrl": null,
                "msg": "你好，我仰慕你的才华！",
                "shield": 0,
                "star": 0,
                "friendNickname": "Auto",
                "origin": 202,
                "black": 0,
                "memo": null,
                "updateTime": 1591169560092,
                "type": 2,
                "userId": 1268082752079560705,
                "friendId": 1267735866185383938,
                "createTime": 1591169491390,
                "blackUpdateTime": 0,
                "addUpdateTime": 1591169560092,
                "id": 1268082872854523906,
                "close": 0,
                "status": 2
            },
            {
                "friendHeadLogoUrl": null,
                "msg": "你好，我仰慕你的才华！",
                "shield": 0,
                "star": 0,
                "friendNickname": "Auto",
                "origin": 202,
                "black": 0,
                "memo": null,
                "updateTime": 1591169560126,
                "type": 2,
                "userId": 1268082752079560705,
                "friendId": 1267735867363983362,
                "createTime": 1591169491862,
                "blackUpdateTime": 0,
                "addUpdateTime": 1591169560126,
                "id": 1268082874830041089,
                "close": 0,
                "status": 2
            },
            {
                "friendHeadLogoUrl": null,
                "msg": "你好，我仰慕你的才华！",
                "shield": 0,
                "star": 0,
                "friendNickname": "Auto",
                "origin": 202,
                "black": 0,
                "memo": null,
                "updateTime": 1591169560164,
                "type": 2,
                "userId": 1268082752079560705,
                "friendId": 1267735867825356802,
                "createTime": 1591169492296,
                "blackUpdateTime": 0,
                "addUpdateTime": 1591169560164,
                "id": 1268082876654563330,
                "close": 0,
                "status": 2
            },
            {
                "friendHeadLogoUrl": null,
                "msg": "你好，我仰慕你的才华！",
                "shield": 0,
                "star": 0,
                "friendNickname": "Auto",
                "origin": 202,
                "black": 0,
                "memo": null,
                "updateTime": 1591169560310,
                "type": 2,
                "userId": 1268082752079560705,
                "friendId": 1267735867003273217,
                "createTime": 1591169493876,
                "blackUpdateTime": 0,
                "addUpdateTime": 1591169560310,
                "id": 1268082883277369345,
                "close": 0,
                "status": 2
            },
            {
                "friendHeadLogoUrl": null,
                "msg": "你好，我仰慕你的才华！",
                "shield": 0,
                "star": 0,
                "friendNickname": "Auto",
                "origin": 202,
                "black": 0,
                "memo": null,
                "updateTime": 1591169560376,
                "type": 2,
                "userId": 1268082752079560705,
                "friendId": 1267735868571942913,
                "createTime": 1591169494629,
                "blackUpdateTime": 0,
                "addUpdateTime": 1591169560376,
                "id": 1268082886439874561,
                "close": 0,
                "status": 2
            }
        ],
        "timestamp": null
    },
    "codeMsg": "success"
}

1、提取某个特定的值

Jsonpath	结果
$.data.total	10
$..total	10
$..items[1].userId	1268082752079560705

2、提取多个值

• 比如要提取items列表里所有的friendId

$..friendId

$..[*].friendId

$.data.items[*].friendId

三种写法都可以，结果为：

Result[0]=1267735865761759234
Result[1]=1267735866185383938
Result[2]=1267735867363983362
Result[3]=1267735867825356802
Result[4]=1267735864650268673
Result[5]=1267735865363300353
Result[6]=1267735866688700417
Result[7]=1267735867003273217
Result[8]=1267735868232204289
Result[9]=1267735868571942913

注意：

1. 使用时，需要用下标读取，如${friend_id_1}、${friend_id_2}........

2. 特别说明一下，如果想要获取返回元素的数量，可以用${friend_id_matchNr}

3. 也可以使用foreach控制器循环读取，这里不再描述。

3、按条件提取值

有时候只需要提取某个特定条件下的参数，比如现在想要提取创建时间为1591169490879的friendId

$.data.items[?(@.createTime ==1591169490879)].friendId

4、阵列提取

提取任何节点的某个key的值，比如提取friendId

$..friendId

结果为：

friend_all_1=1267735865761759234
friend_all_10=1267735868571942913
friend_all_2=1267735866185383938
friend_all_3=1267735867363983362
friend_all_4=1267735867825356802
friend_all_5=1267735864650268673
friend_all_6=1267735865363300353
friend_all_7=1267735866688700417
friend_all_8=1267735867003273217
friend_all_9=1267735868232204289
friend_all_ALL=1267735865761759234,1267735866185383938,1267735867363983362,1267735867825356802,1267735864650268673,1267735865363300353,1267735866688700417,1267735867003273217,1267735868232204289,1267735868571942913
friend_all_matchNr=10

_ALL下标是将所有元素组成一个list，像后续接口有时候参数是以数组形式来传参，这个函数就很有用，如果需要返回此函数，需要在json提取器中，勾选Compute concatenation var

5、提取多个值

json表达式：

$..['msg','friendId']

返回的变量如下：

two_1={"msg":"你好，我仰慕你的才华！","friendId":1267735865761759234}
two_10={"msg":"你好，我仰慕你的才华！","friendId":1267735868571942913}
two_2={"msg":"你好，我仰慕你的才华！","friendId":1267735866185383938}
two_3={"msg":"你好，我仰慕你的才华！","friendId":1267735867363983362}
two_4={"msg":"你好，我仰慕你的才华！","friendId":1267735867825356802}
two_5={"msg":"你好，我仰慕你的才华！","friendId":1267735864650268673}
two_6={"msg":"你好，我仰慕你的才华！","friendId":1267735865363300353}
two_7={"msg":"你好，我仰慕你的才华！","friendId":1267735866688700417}
two_8={"msg":"你好，我仰慕你的才华！","friendId":1267735867003273217}
two_9={"msg":"你好，我仰慕你的才华！","friendId":1267735868232204289}
two_ALL={"msg":"你好，我仰慕你的才华！","friendId":1267735865761759234},{"msg":"你好，我仰慕你的才华！","friendId":1267735866185383938},{"msg":"你好，我仰慕你的才华！","friendId":1267735867363983362},{"msg":"你好，我仰慕你的才华！","friendId":1267735867825356802},{"msg":"你好，我仰慕你的才华！","friendId":1267735864650268673},{"msg":"你好，我仰慕你的才华！","friendId":1267735865363300353},{"msg":"你好，我仰慕你的才华！","friendId":1267735866688700417},{"msg":"你好，我仰慕你的才华！","friendId":1267735867003273217},{"msg":"你好，我仰慕你的才华！","friendId":1267735868232204289},{"msg":"你好，我仰慕你的才华！","friendId":1267735868571942913}
two_matchNr=10