How can variables be custom generated randomly in JMeter?

1 year ago
William Carter
2 minutes

In JMeter, you can use the following methods to customize variables for random generation:

  1. Utilize the built-in functions in JMeter: JMeter offers a variety of built-in functions that can be used to generate random values. For example, you can use the ${__Random(1,100)} function to generate a random integer between 1 and 100. This way, ${__Random(1,100)} can be used as a variable in the test plan.
  2. JMeter also offers specialized functions for generating random variables using the Random Variable function. For example, the ${__RandomString(10,abcdefghijklmnopqrstuvwxyz)} function can generate a random string of length 10 with lowercase letters. This allows the ${__RandomString(10,abcdefghijklmnopqrstuvwxyz)} function to be used as a variable in the test plan.
  3. Utilizing BeanShell scripts: For more complex random values, custom functions can be written using BeanShell scripts. For example, the following BeanShell script can be used to generate a random string containing numbers and letters:
import java.util.Random;

String generateRandomString(int length) {
    String characters = "abcdefghijklmnopqrstuvwxyzABCDEFGHIJKLMNOPQRSTUVWXYZ0123456789";
    StringBuilder stringBuilder = new StringBuilder();

    Random random = new Random();
    for (int i = 0; i < length; i++) {
        int index = random.nextInt(characters.length());
        char randomChar = characters.charAt(index);
        stringBuilder.append(randomChar);
    }

    return stringBuilder.toString();
}

String randomString = generateRandomString(10);
vars.put("randomString", randomString);

Then, use this script in the BeanShell PreProcessor or PostProcessor in JMeter to store the generated random string in a variable (in the example above, it is randomString). This way, you can use ${randomString} in the test plan to reference this random string variable.

The above are some common methods, and depending on specific requirements, other JMeter functions and custom scripts can also be combined to generate custom random variables.

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