The connection is Jmeter A very important technology in tools . Because in the process of testing, some data is often changed , To get and use this data , We're going to use correlation .

such as ： After the user logs in ,session The information is different , Some operations need to use session, You need to save this dynamic information . There are also scenes that we often encounter , The parameters submitted by the second request are obtained from the return data of the first request .

The specific methods ：

One 、 Regular expression extractor

  Add a thread group to the default test plan , Then add the sampler .

Right click to add post processor → Regular expression extractor , The regular expression extractor interface is as follows ：

• explain ：

  Post Processors ： Play a role at the end of a request or when a response is returned

  Regular expression extractor ： Allow users to use... From the server's response perl The regular expression extract value of . This element acts on the specified range sampler , Extract the required value with regular expression , Generate template string , And store the result in the given variable name .

• APPly to: Scope of action （ Returns the assertion range of the content ）

  Main sample and sub-samples: The sampler acting on the parent node and the sampler corresponding to the child node

  Main sample only： Samplers acting only on the parent node

  Sub-samples only: Samplers acting only on child nodes

  JMeter Variable: Act on jmeter Variable ( Enter... In the input box jmeter The variable name of )

• Response fields to check ： The range of response messages to be checked

  The main body ： The body of the response message

  Body(unescaped): The main body , The main content of the response and all of the html Escape character , Be careful html Escape characters are processed without regard to context , So there may be incorrect conversions , Not recommended

  Body as a Document： Extract text from different types of files , Note that this option affects performance

  Response Headers： Response headers

  Request Headers: Request headers

  URL： Uniform resource locator , namely Internet The string used to describe information resources

  Response code : Response status code , such as 200、404 etc.

  Response information : Response information  

• Quote name （Reference Name）：Jmeter The name of the variable , Store the extracted results ; The value to be referenced by the next request 、 Field 、 Variable name （ What I extracted from the example is SOCIAL_NO）

• Regular expressions （Regular Expression）： Use regular expressions to parse response results ,“（）” Represents extracting partial values from a string , Please do not use “||”, Unless you need to match the character yourself .

        Common regular expression operators ：

• Templates ： Represents the style referenced from the regular expression result , In fact, the result is a group of , Instead of a .$0$ Represents all of this set of results ,$1$ The number one that represents this set of results 1 individual , And so on ;$1$$2$ Represents the... Th in a set of results of the regular expression 1 And the first 2 individual , The two ended up next to each other without a gap between them ;$3$,$4$ Represents the... Th in a set of results of the regular expression 3 And the first 4 individual , There is a comma between the two results .

• Match the Numbers ：0 Represents random... In the regular expression result group ,1 Represent all .

• The default value ： Display the information passed when the reference is not correct , Write one smoothly ERROR.

Last , Follow the instructions above , Complete the configuration , Then you can add a monitor first （ View the result tree ）, Check whether the corresponding value is taken ; The extracted parameters , Use when calling ${sessionid_1},${sessionid_2}..., If you want to get the number of matched parameters ,${sessionid_matchNr}.

Two 、json path postprocessor（JSON Extractor）

use ：

The current interface response returns json Extract content from , As a variable, it can be passed in different requests . as follows , From the login interface json Extract from user id, The variable name is set to id, You can call this variable directly in other requests , Or as post Parameters . Secondary plug-in for restful The interface is very easy to use .

• Variable names :  name

• JSONPath Expression：JSON expression

• Match Numbers： Match which , It can be empty, that is, the first one is the default

• Default Value： When no value is taken, the default value is

For example, the return value is as follows ：

1{
2    "userSession": {
3        "businessCode": "900000",
4        "createTime": "2018-05-25 03:24:17",
5        "userCode": "29feaa3c98014e02bec16c6f448a6459",
6        "userName": "lip-vpn",
7        "sessionId": "10a4cee035d044d8b2f25e2cebb2843e"
8    }
9}

• be json Expression for ：$.userSession.sessionId

If the return value is an array , You need to add the position of the array , Such as

1{
2    "userSession": [
3        {
4            "businessCode": "900000",
5            "createTime": "2018-05-25 03:24:17",
6            "userCode": "29feaa3c98014e02bec16c6f448a6459",
7            "userName": "lip-vpn",
8            "sessionId": "10a4cee035d044d8b2f25e2cebb2843e"
9        }
10    ]
11}

be json Expression for ：$.userSession[0].sessionId, Extract the first value .

3、 ... and 、XPath Extractor

Jmeter The support provided for association includes the following 2 In terms of ：

① It can save the specified content on the returned page in the parameter ;（ Regular expression extractor and JSON Extractor）

② To be able to GET or POST The data in the method is replaced with this parameter ;(XPath Extractor)

• XPath Extractor And regular expression extractor (Regular Expression Extractor) similar , It's just that Expression Is not a regular expression specified in , It's given XPath route .

• Post Processors (Post Processor) In essence, it's a kind of right sampler After sending the request, the received response data is processed （ post-processing ） Methods . The postprocessor components must be placed in the right place to achieve the desired effect .

• Create a new thread group , And then right-click - add to - Post Processors -XPath Extractor：

  

• APPly to: Scope of action （ Returns the assertion range of the content ）

         Main sample and sub-samples: The sampler acting on the parent node and the sampler corresponding to the child node

         Main sample only： Samplers acting only on the parent node

         Sub-samples only: Samplers acting only on child nodes

         JMeter Variable: Act on jmeter Variable ( Enter... In the input box jmeter The variable name of )

• XML Parsing Options： To parse XML Parameters

  Use Tidy： When the page to be processed is HTML When the format , You must check this option ; If it is XML or XHTML Format （ for example RSS return ）, Then uncheck ;

  Quiet Show only what you need HTML page ,Report errors Indicates that the display response reports an error ,Show warnings Indicates that a warning is displayed ;

  Use Namespaces： If this option is enabled , Follow up XML The parser will use the namespace to distinguish ;

         Validate XML： Check and parse according to the page element pattern ;

         Ignore Whitespace： Ignore blank content ;

          Fetch external DTDs： If it is checked , The outside will use DTD Rules to get page content ;

• Return entire XPath fragment of  text content： Return the whole content of the text XPath fragment ;

• Reference Name： Parameters that store the extracted values .

• XPath Query： For extracting values XPath expression .

• Default Value： The default value of the parameter .

• Regular expression extractors and XPath Extractor The difference between ：

① Regular expression extractor can be used to extract any text from a page , The extracted content is text matching in the page content according to the regular expression ;

②XPath Extractor You can extract any attribute of any element on the returned page ;

③ If the text to be extracted is the attribute value of an element on the page , It is recommended to use XPath Extractor;

④ If the position of the text to be extracted on the page is not fixed , Or not an attribute of an element , Regular expression extractors are recommended .

Finally, thank everyone who reads my article carefully , Watching the rise and attention of fans all the way , Reciprocity is always necessary , Although it's not very valuable , If you can use it, you can take it

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