无法从JMeter的JSR223 Sampler中获取值问题求助

Hey there, let's work through why your JSR223 Sampler isn't pulling the values you expect. I spotted a few key issues in your code that are likely blocking the logic from running correctly—let's break them down and fix it step by step:

1. Incorrect Size Comparison Logic #

Your code compares options.size() (which returns an integer) to string values "1" and "2". Integer-to-string comparisons will never evaluate to true, so the entire block inside your if statement never executes.

Fix: Swap the string literals for integer values:

if(options.size() == 1 || options.size() == 2) {

2. Truncated RandomUtils Method Call #

Your code cuts off at RandomUtils.nextInt(0, va...—this is missing the upper bound parameter, which should be values.size() to pick a valid random index within the values list. A malformed method call here will throw an error and stop the script in its tracks.

Fix: Complete the method call properly:

def randomValue = values.get(RandomUtils.nextInt(0, values.size()))

3. Add Null Safety Checks #

To avoid unexpected NullPointerExceptions (for example, if options or values is empty or null), add quick guard clauses before accessing their properties.

Corrected Full Code #

Here's the revised code with all fixes plus debug logs to help you verify each step of the process:

import com.jayway.jsonpath.JsonPath
import org.apache.commons.lang3.RandomUtils
import org.apache.jmeter.samplers.SampleResult

// Capture and log the previous sampler's response for debugging
def prevResponse = prev.getResponseDataAsString()
log.info("Previous sampler response: " + prevResponse)

// Extract the options array from the response
def options = JsonPath.read(prevResponse, '$.options')
log.info("Extracted options count: " + options.size())

// Validate options size with integer comparisons + null check
if(options != null && (options.size() == 1 || options.size() == 2)) {
    def randomOption = options.get(0)
    log.info("Selected option data: " + randomOption)
    
    // Extract and store the 'code' value
    def code = randomOption.get("code")
    vars.put('code1', code)
    log.info("Stored 'code1' variable: " + code)
    
    // Extract values list and pick a random entry
    def values = randomOption.get('values')
    if(values != null && !values.isEmpty()) {
        def randomValue = values.get(RandomUtils.nextInt(0, values.size()))
        log.info("Selected random value: " + randomValue)
        // Optional: Store the random value in a JMeter variable if needed
        // vars.put('selectedValue', randomValue.toString())
    } else {
        log.warn("Values list is null or empty—can't pick a random value!")
    }
} else {
    log.warn("Options list is null or doesn't have 1/2 items—skipping logic!")
}

Quick Debugging Tips #

• Open the JMeter Log Viewer (View → Log Viewer) to check the debug messages from the log.info() calls. This will tell you:
  • If the previous sampler's response matches what you expect
  • If the options array is being extracted correctly
  • Whether your code is entering the if blocks as intended
• Test your JSON Path expression $.options using JMeter's built-in JSON Path Tester (under the Tools menu) to confirm it targets the right data in your response.

内容的提问来源于stack exchange，提问作者Suresh