title: How can I set the multipart boundary with JMeter
body: <p>I'm using this guide to send a multipart POST request to a server with JMeter: <a href="https://www.blazemeter.com/blog/testing-advanced-rest-api-file-uploads-jmeter" rel="nofollow noreferrer">https://www.blazemeter.com/blog/testing-advanced-rest-api-file-uploads-jmeter</a></p>
  
  <p>In this request there are several parts like a file, some strings and JSON.</p>
  
  <p>The problem is, although I specify the boundary in the "Content type" field, JMeter set whatever it wants and the result is the server (Wildfly 10) correctly rejects the request with a "RESTEASY007500: Could find no Content-Disposition header within part".</p>
  
  <p>Here the request configuration:</p>
  
  <p><a href="https://i.stack.imgur.com/NMZ9A.jpg" rel="nofollow noreferrer"><img src="https://i.stack.imgur.com/NMZ9A.jpg" alt="enter image description here"></a></p>
  
  <p>And here the generated request:</p>
  
  <p><a href="https://i.stack.imgur.com/RTQ4y.jpg" rel="nofollow noreferrer"><img src="https://i.stack.imgur.com/RTQ4y.jpg" alt="enter image description here"></a></p>
  
  <p>I set "jmeter_is_great" but JMeter generates a random boundary.
  Is someone having the same problem? Am i doing something wrong?</p>
  
  <p>Thanks</p>
  
  <p><strong>UPDATE</strong></p>
  
  <p>I asked how to set the boundary because at the beginning of my test the first error throwed by the server was "RESTEASY007550: Unable to get boundary for multipart".
  So I added the "Content type" field, which can contain the boundary value, but that doesn't seem to work.
  I was not really interested to set a specific boundary at the beginning.</p>
  
  <p>Now, I found a configuration <strong>which work although without specify the boundary</strong>, maybe someone can find it useful:</p>
  
  <p><a href="https://i.stack.imgur.com/cCAsc.jpg" rel="nofollow noreferrer"><img src="https://i.stack.imgur.com/cCAsc.jpg" alt="enter image description here"></a></p>
  
  <p><a href="https://i.stack.imgur.com/Ou4Nn.jpg" rel="nofollow noreferrer"><img src="https://i.stack.imgur.com/Ou4Nn.jpg" alt="enter image description here"></a></p>