BeanShell PostProcessor执行Java代码编译错误，无法写入CSV文件

我尝试用JMeter的BeanShell PostProcessor编写代码，将接口返回的JSON数据写入CSV文件，代码如下：

import java.io.File;
import java.io.FileNotFoundException;
import java.io.FileWriter;
import java.io.IOException;
import org.json.simple.JSONArray;
import org.json.simple.JSONObject;
import org.json.simple.parser.JSONParser;
import org.json.simple.parser.ParseException;
import com.opencsv.CSVWriter;

public class CsvWrite{
    public static void main(String[] args){
String response = prev.getResponseDataAsString();
        JSONParser parser = new JSONParser();
        File file = new File("D:\\verisk\\first_url_response.csv");

        try {
            FileWriter fileWriter = new FileWriter(file);
            CSVWriter csvWriter = new CSVWriter(fileWriter);

            // adding header to csv
            String[] header = { "id", "title", "description", "price", "discountPercentage", "rating", "stock",
                    "brand" };
            csvWriter.writeNext(header);

            Object obj = parser.parse(response);
            JSONObject jsonObject = (JSONObject) obj;

            JSONArray productArray = (JSONArray) jsonObject.get("products");

            int productArraySize = productArray.size();
            for (int i = 0; i < productArraySize; i++) {
                JSONObject productDetailObject = (JSONObject) productArray.get(i);
                String id = (productDetailObject.get("id").toString());
                String title = (productDetailObject.get("title").toString());
                String price = (productDetailObject.get("price").toString());
                String description = (productDetailObject.get("description").toString());
                String discountPercentage = (productDetailObject.get("discountPercentage").toString());
                String rating = (productDetailObject.get("rating").toString());
                String stock = (productDetailObject.get("stock").toString());
                String brand = (productDetailObject.get("brand").toString());

                String[] productDetails = { id, title, description, price, discountPercentage, rating, stock, brand };
                csvWriter.writeNext(productDetails)
            }
            fileWriter.close();

        } catch (ParseException e) {
            // TODO Auto-generated catch block
            e.printStackTrace();
        } catch (IOException e) {
            // TODO Auto-generated catch block
            e.printStackTrace();
        }
    }

}

运行后无法写入CSV，日志报错：

2023-01-02 14:41:06,853 ERROR o.a.j.u.BeanShellInterpreter: Error invoking bsh method: eval In file: inline evaluation of: ``import java.io.File; import java.io.FileNotFoundException; import java.io.FileWr . . . '' Encountered "}" at line 44, column 25.

附带日志信息：

2023-01-02 14:41:06,853 INFO o.a.j.t.JMeterThread: Thread is done: Thread Group 1-1
2023-01-02 14:41:06,853 INFO o.a.j.t.JMeterThread: Thread finished: Thread Group 1-1
2023-01-02 14:41:06,854 INFO o.a.j.e.StandardJMeterEngine: Notifying test listeners of end of test
2023-01-02 14:41:06,854 INFO o.a.j.g.u.JMeterMenuBar: setRunning(false, local)

注：已将json-simple-1.1.jar和opencsv-4.1.jar放入JMeter的lib目录，代码在Eclipse中可正常运行。

问题原因与修复 #

1. 语法错误：缺少分号
   报错位置对应代码中csvWriter.writeNext(productDetails)一行，末尾缺少分号，BeanShell对语法要求严格，这是解析失败的直接原因。

2. BeanShell无需类和main方法
   BeanShell PostProcessor直接执行脚本代码，不需要像Java类那样定义CsvWrite类和main方法，多余的类结构会导致执行异常。

修正后的代码 #

import java.io.File;
import java.io.FileWriter;
import java.io.IOException;
import org.json.simple.JSONArray;
import org.json.simple.JSONObject;
import org.json.simple.parser.JSONParser;
import org.json.simple.parser.ParseException;
import com.opencsv.CSVWriter;

// 获取接口响应数据
String response = prev.getResponseDataAsString();
JSONParser parser = new JSONParser();
File file = new File("D:\\verisk\\first_url_response.csv");

try {
    FileWriter fileWriter = new FileWriter(file);
    CSVWriter csvWriter = new CSVWriter(fileWriter);

    // 写入CSV表头
    String[] header = { "id", "title", "description", "price", "discountPercentage", "rating", "stock", "brand" };
    csvWriter.writeNext(header);

    Object obj = parser.parse(response);
    JSONObject jsonObject = (JSONObject) obj;

    JSONArray productArray = (JSONArray) jsonObject.get("products");

    int productArraySize = productArray.size();
    for (int i = 0; i < productArraySize; i++) {
        JSONObject productDetailObject = (JSONObject) productArray.get(i);
        String id = productDetailObject.get("id").toString();
        String title = productDetailObject.get("title").toString();
        String price = productDetailObject.get("price").toString();
        String description = productDetailObject.get("description").toString();
        String discountPercentage = productDetailObject.get("discountPercentage").toString();
        String rating = productDetailObject.get("rating").toString();
        String stock = productDetailObject.get("stock").toString();
        String brand = productDetailObject.get("brand").toString();

        String[] productDetails = { id, title, description, price, discountPercentage, rating, stock, brand };
        csvWriter.writeNext(productDetails); // 补充分号
    }
    // 正确关闭资源
    csvWriter.close();
    fileWriter.close();

} catch (ParseException e) {
    e.printStackTrace();
} catch (IOException e) {
    e.printStackTrace();
}

额外优化建议 #

• 优先使用JSR223 PostProcessor + Groovy替代BeanShell，Groovy性能更优，语法兼容性更强。
• 若需要保留历史数据，可将FileWriter(file)改为FileWriter(file, true)启用追加模式。

内容的提问来源于stack exchange，提问作者Sandesh