JMeter实现WebSocket压测：循环生成消息并添加至数组的方法

Got it, let's walk through how to set this up step by step—no prior Java/Beanshell experience required! We'll use a CSV Data Set Config to pull your message content, and a Beanshell PreProcessor to dynamically add new entries to the body array each time we send a request.

Step 1: Prepare Your CSV File #

First, make sure your CSV is formatted correctly:

• Create a file (e.g., messages.csv) with a single column header MESSAGE
• Each row below the header should contain one message content (the value you want for the body field in your new entry)

Example CSV content:

MESSAGE
new message again
another test message
third message to send

Step 2: Add CSV Data Set Config to Your Thread Group #

1. Right-click your Thread Group > Add > Config Element > CSV Data Set Config
2. Configure it like this:
   • Filename: Path to your messages.csv file
   • Variable Names: MESSAGE (matches the header in your CSV)
   • Recycle on EOF: Check this if you want to loop through the CSV entries when you reach the end (good for long load tests)
   • Stop thread on EOF: Uncheck this if you're recycling
   • Delimiter: , (default, since it's a CSV)

Step 3: Add Beanshell PreProcessor to Your WebSocket Request #

1. Right-click your WebSocket Request > Add > Pre Processors > Beanshell PreProcessor
2. Paste the following script into the "Script" field. I've added comments to explain each part:

// 1. Start with your base message template (matches the format you provided)
String baseMessage = "42[\"tickets\",\"ticket_message\", {\"ticket\":{ \"body\":[{\"received\":\"2018-05-17T11:28:51.000Z\",\"fromName\":\"Jesper Pedersen\",\"body\":\"test\\n\"}, {\"received\":\"2018-05-17T13:30:53+02:00\",\"body\":\"Yo\",\"fromName\":\"Futurum Digital\"} ] }}]";

// 2. Remove the Socket.IO prefix "42" to get the raw JSON array
String jsonContent = baseMessage.substring(2);

// 3. Parse the JSON array using JMeter's built-in JSON library
org.json.JSONArray mainArray = new org.json.JSONArray(jsonContent);

// 4. Navigate to the ticket's body array
org.json.JSONObject ticketWrapper = mainArray.getJSONObject(2);
org.json.JSONObject ticket = ticketWrapper.getJSONObject("ticket");
org.json.JSONArray bodyArray = ticket.getJSONArray("body");

// 5. Create your new message entry
org.json.JSONObject newEntry = new org.json.JSONObject();
// Generate current UTC timestamp in the format from your example
newEntry.put("received", new java.text.SimpleDateFormat("yyyy-MM-dd'T'HH:mm:ss.SSS'Z'").format(new java.util.Date()));
// Pull the message content from your CSV variable
newEntry.put("body", vars.get("MESSAGE"));
newEntry.put("fromName", "Futurum Digital");

// 6. Add the new entry to the body array
bodyArray.put(newEntry);

// 7. Reassemble the full Socket.IO message
String finalMessage = "42" + mainArray.toString();

// 8. Store the final message in a JMeter variable to use in your request
vars.put("DYNAMIC_WEBSOCKET_MESSAGE", finalMessage);

Step 4: Configure Your WebSocket Request #

In your WebSocket Request's Message Data field, replace any static content with the variable we created:

${DYNAMIC_WEBSOCKET_MESSAGE}

Optional Adjustment: Start with an Empty Body Array #

If you don't want to keep the initial two entries in the body array and want to start fresh each time, add this line right after getting the bodyArray:

// Clear existing entries to start with an empty array
bodyArray = new org.json.JSONArray();

That's it! Now each time your thread runs, it will pull a new message from the CSV, add it to the body array, and send the updated WebSocket message.

内容的提问来源于stack exchange，提问作者Jesper