jmeter beanshell获取返回值并保存到文件中

//提取响应内容
String statusCode = prev.getResponseCode(); //获取响应代码
String response_body = prev.getResponseDataAsString(); //获取响应body内容
String response_headers = prev.getResponseHeaders();   //获取响应头
String response_reason = prev.getResponseMessage();   //获取响应信息

log.info("=====响应代码：=====>>"+statusCode);
log.info("=====响应body:=====>>"+response_body);
log.info("=====响应头：=====>>"+response_headers);
log.info("=====响应信息：=====>>"+response_reason);
import org.json.JSONObject;
import org.json.JSONArray;
JSONObject JsonData = new JSONObject(response_body);//json格式化

log.info("=====JsonData：=====>>"+JsonData);
String strdata = JsonData.get("data").get("ocTrackingNumber").toString();

log.info("=====data：=====>>"+strdata);

String filename = "C:\\Users\\Desktop\\单号.txt";
FileWriter writer;
        try {
            writer = new FileWriter(filename,true);
            writer.write(strdata);
            writer.write("\r\n");
            writer.flush();
            writer.close();
        } catch (IOException e) {
            e.printStackTrace();
        }