Foreword

Now many login interface is to return a json data, token value in the json returned inside, you can extract the value in the json which directly jmeter inside.
Return token on an interface of the interface as the next reference.

Case scenario

I now have a landing interfaces A, returns a token value after a successful landing. There is a binding acquisition card interface B, but B must first login interface to transfer token to log in to access
the A interface login interface documentation basic information

Access Address: http://127.0.0.1:8000/api/v1/login/
Request Type: POST
Request header: application / json
请求参数：{"username":"test", "password":"123456"}

A request interface and return the following message information

D:\>http http://127.0.0.1:8000/api/v1/login/ username=test password=123456 -v
POST /api/v1/login/ HTTP/1.1
Accept: application/json, */*
Accept-Encoding: gzip, deflate
Connection: keep-alive
Content-Length: 42
Content-Type: application/json
Host: 127.0.0.1:8000
User-Agent: HTTPie/1.0.3

{
    "password": "123456",
    "username": "test"
}

HTTP/1.1 200 OK
Allow: POST, OPTIONS
Content-Length: 109
Content-Type: application/json
Date: Sat, 21 Sep 2019 15:37:06 GMT
Server: WSGIServer/0.2 CPython/3.6.0
Vary: Accept, Cookie
X-Frame-Options: SAMEORIGIN

{
    "code": 0,
    "msg": "login success!",
    "token": "234af73571da46ade79ea6a74961b1d23d609b79",
    "username": "test"
}

B interface card interface to obtain binding document basic information

Access Address: http://127.0.0.1:8000/api/v1/user/info/
Request Type: GET
Request headers: Content-Type: application / json
Request header token argument: Authorization: Token xxxxx login token xxxxx

Login request

First add http request jmeter inside, fill in login interface parameters

HTTP header added post request manager Type: Content-Type: application / json

After running to see the number of results, you can see the correct return token values we want

Json extractor

Add extractor postprocessor -Json

Token values extracted from the returned results

Return result

{
    "code": 0,
    "msg": "login success!",
    "token": "234af73571da46ade79ea6a74961b1d23d609b79",
    "username": "test"
}

JSON extractor parameters:

Names of created variables parameter name
JSON Path expressions extraction expression
Match No.(0 for Random) 匹配规则,-1所有,0随机,1第一个
Compute concatenation va 如果有匹配到多个值，选择此项，会将全部值保存到_ALL，并使用逗号分割每个值，注意Match No. (0 for Random)需要为-1才有效，不然只能匹配到一个值了
Default Values 没提取到就给默认值