要将数据写入Excel中的多个工作表，可以使用Apache Spark的DataFrameWriter功能来实现。下面是一个使用Scala语言的代码示例：

import org.apache.spark.sql.{DataFrame, SparkSession}

object SparkExcelWriter {
  def main(args: Array[String]): Unit = {
    val spark = SparkSession.builder()
      .appName("SparkExcelWriter")
      .master("local")
      .getOrCreate()

    val data = Seq(
      ("John", 25, "USA"),
      ("Mike", 30, "UK"),
      ("Anna", 35, "Germany")
    )

    val df = spark.createDataFrame(data).toDF("Name", "Age", "Country")

    val outputFilePath = "path/to/output.xlsx"
    val sheetNames = Seq("Sheet1", "Sheet2", "Sheet3")

    writeExcel(df, outputFilePath, sheetNames)

    spark.stop()
  }

  def writeExcel(df: DataFrame, outputFilePath: String, sheetNames: Seq[String]): Unit = {
    val workbook = new org.apache.poi.xssf.usermodel.XSSFWorkbook()

    sheetNames.foreach(sheetName => {
      val sheet = workbook.createSheet(sheetName)
      val headerRow = sheet.createRow(0)

      // Write column names as headers
      df.schema.fields.zipWithIndex.foreach { case (field, index) =>
        headerRow.createCell(index).setCellValue(field.name)
      }

      // Write data rows
      df.collect().zipWithIndex.foreach { case (row, rowIndex) =>
        val dataRow = sheet.createRow(rowIndex + 1)

        row.toSeq.zipWithIndex.foreach { case (value, columnIndex) =>
          val cell = dataRow.createCell(columnIndex)
          cell.setCellValue(value.toString)
        }
      }
    })

    val fileOut = new java.io.FileOutputStream(outputFilePath)
    workbook.write(fileOut)
    fileOut.close()
    workbook.close()
  }
}

请注意，这个示例假定你已经在项目中添加了Apache POI库的依赖。