在運行Jmeter腳本時獲取Transformer異常

Question

在使用3個線程運行我的JMeter腳本時，漸增5秒我收到變換器異常。實際上，在我的場景中，我想隨機點擊頁面的多個鏈接，因此我在JMeter中使用了隨機變量。但是在運行後，我得到了錯誤，但是，XPath提取器中的XPath表達式看起來很好。

2016/09/23 23:44:03 INFO - jmeter.engine.StandardJMeterEngine: Running the test! 
2016/09/23 23:44:03 INFO - jmeter.samplers.SampleEvent: List of sample_variables: [] 
2016/09/23 23:44:03 INFO - jmeter.gui.util.JMeterMenuBar: setRunning(true,*local*) 
2016/09/23 23:44:03 INFO - jmeter.engine.StandardJMeterEngine: Starting ThreadGroup: 1 : Thread Group 
2016/09/23 23:44:03 INFO - jmeter.engine.StandardJMeterEngine: Starting 3 threads for group Thread Group. 
2016/09/23 23:44:03 INFO - jmeter.engine.StandardJMeterEngine: Thread will continue on error 
2016/09/23 23:44:03 INFO - jmeter.threads.ThreadGroup: Starting thread group number 1 threads 3 ramp-up 5 perThread 1666.6666 delayedStart=false 
2016/09/23 23:44:03 INFO - jmeter.threads.JMeterThread: Thread started: Thread Group 1-1 
2016/09/23 23:44:03 INFO - jmeter.threads.ThreadGroup: Started thread group number 1 
2016/09/23 23:44:03 INFO - jmeter.engine.StandardJMeterEngine: All thread groups have been started 
2016/09/23 23:44:05 INFO - jmeter.threads.JMeterThread: Thread started: Thread Group 1-2 
2016/09/23 23:44:07 INFO - jmeter.threads.JMeterThread: Thread started: Thread Group 1-3 
2016/09/23 23:44:09 WARN - jmeter.extractor.XPathExtractor: TransformerException while processing ((//span[@class="title"]/a/@href)[$(RandomNumber)]) Expected ], but found: RandomNumber 
2016/09/23 23:44:10 INFO - jmeter.threads.JMeterThread: Thread is done: Thread Group 1-1 
2016/09/23 23:44:10 INFO - jmeter.threads.JMeterThread: Thread finished: Thread Group 1-1 
2016/09/23 23:44:10 WARN - jmeter.extractor.XPathExtractor: TransformerException while processing ((//span[@class="title"]/a/@href)[$(RandomNumber)]) Expected ], but found: RandomNumber 
2016/09/23 23:44:11 INFO - jmeter.threads.JMeterThread: Thread is done: Thread Group 1-3 
2016/09/23 23:44:11 INFO - jmeter.threads.JMeterThread: Thread finished: Thread Group 1-3 
2016/09/23 23:44:11 WARN - jmeter.extractor.XPathExtractor: TransformerException while processing ((//span[@class="title"]/a/@href)[$(RandomNumber)]) Expected ], but found: RandomNumber 
2016/09/23 23:44:12 INFO - jmeter.threads.JMeterThread: Thread is done: Thread Group 1-2 
2016/09/23 23:44:12 INFO - jmeter.threads.JMeterThread: Thread finished: Thread Group 1-2 
2016/09/23 23:44:12 INFO - jmeter.engine.StandardJMeterEngine: Notifying test listeners of end of test 
2016/09/23 23:44:12 INFO - jmeter.gui.util.JMeterMenuBar: setRunning(false,*local*) 

Answer 1

1. JMeter Variables被引用爲${RandomNumber} - 你需要使用大括號，而不是括號。或者您可以使用__V()功能像

   ${__V(RandomNumber)} 
   

   所以，你需要你的XPath查詢更改爲以下之一：

   • （//跨度[@類= 「標題」]/A/@ HREF）[$ {RandomNumber}]
   • （//跨度[@類= 「標題」] /一個/ @ HREF）[$ {__ V（RandomNumber）}]

2. 你的方法似乎是脆弱。我不知道有多少鏈接頁面，你如何生成您${RandomNumber}變量，但我寧願去以下方式：

   • 商店所有鏈接頁面到像JMeter的變量：

     link_1=http://example.com 
     link_2=http://jmeter.apache.org 
     ... 
     link_matchNr=50 
     

   • 使用隨機變量的JMeter從那裏經由上述__V()__Random()和組合功能所需的像先前提取的：

     ${__V(link_${__Random(1,${link_matchNr},)})} 
     

   演示：

   

   見Here’s What to Do to Combine Multiple JMeter Variables文章，你如何能不同JMeter的函數和變量組合成一個單一的表達更多的信息。