如何修复此代码，我没有收到错误，但数据不会导出到csv

Question

我正在创建一个负载测试，我需要从数据库中获取数据，所以我创建了另一个文件，用于从db获取数据并将其导出到csv文件，以后将该文件用作馈送器，导出到csv isn'工作

import java.io._

import com.github.tototoshi.csv._
import io.gatling.core.Predef._
import io.gatling.core.feeder.SourceFeederBuilder
import io.gatling.jdbc.Predef._

import scala.collection.mutable.ArrayBuffer

class GenerateData extends Simulation {

  val csvFileLocation = new File("data.csv")
  val writers: CSVWriter = CSVWriter.open(csvFileLocation)

  // load and register JDBC driver for MySQL
  Class.forName("com.mysql.cj.jdbc.Driver")

  // DATABASE
  val dbStatement: String = System.getProperty("dbStatement", "SELECT * FROM db limit 1")
  val dbQuery: SourceFeederBuilder[Any] = jdbcFeeder("jdbc:mysql://localhost:3306/table?useUnicode=true&useJDBCCompliantTimezoneShift=true&useLegacyDatetimeCode=false&serverTimezone=UTC", "username", "pass", dbStatement)
//
  var recordCount: Int = dbQuery.readRecords.length
  var mList = new Array[String](recordCount)
  var dataString: ArrayBuffer[String] = ArrayBuffer[String]()
  var dataCounts: ArrayBuffer[Int] = ArrayBuffer[Int]()
  val out = new BufferedWriter(new FileWriter(csvFileLocation))
  val writer = new CSVWriter(out)

  val scn = scenario("Database Query")
    .feed(dbQuery)
    writer.writeRow(dataString)
    writer.close()

  setUp(scn.inject(atOnceUsers(1)))
}

没有任何内容添加到csv文件，我只是从gatling报告错误

能否请你帮忙

Answer 1

你做：

var dataString: ArrayBuffer[String] = ArrayBuffer[String]()
writer.writeRow(dataString)

dataString总是空的，你不会覆盖dataString

Answer 2

我想你的

writer.writeRow(dataString)
 writer.close()

线也需要在适当的gatling dsl步骤？

所以...

val scn = scenario("Database Query")
.feed(dbQuery)
.exec(session -> {
    //code to add the value from you dbQuery feeder to dataString 
    writer.writeRow(dataString)
    writer.close()
    session
})