How does SparkStreaming save data to a relational database

There is no difference between it and Core, that is, foreachRDD is called. The following is an example of stream processing to save wordcount to mysql

object TestStream2 {
    
    

  def main(args: Array[String]): Unit = {
    
    
    val conf = new SparkConf().setMaster("local[2]").setAppName("NetworkWordCount")
    val ssc = new StreamingContext(conf, Seconds(5))

    ssc.sparkContext.setLogLevel("WARN")

    val dataDS: ReceiverInputDStream[String] = ssc.socketTextStream("192.168.182.147",9998)

    val wordDS: DStream[String] = dataDS.flatMap(_.split(" "))

    val tupleDS: DStream[(String, Int)] = wordDS.map((_,1))

    tupleDS.reduceByKey(_+_).foreachRDD(rdd=>{
    
    
      rdd.foreach(word=>{
    
    
        Class.forName("com.mysql.jdbc.Driver")
        //获取mysql连接
        val conn = DriverManager.getConnection("jdbc:mysql://localhost:3306/test", "root", "")
        //把数据写入mysql
        try {
    
    
          var totalcount = word._2
          var sql = "";
          var querysql="select count from wordcount where titleName='"+word._1+"'"
          val queryresult: ResultSet = conn.prepareStatement(querysql).executeQuery()
          if(queryresult.next()){
    
    
            totalcount = queryresult.getString("count").toInt+word._2
            sql = "update wordcount set count='"+totalcount+"' where titleName='"+word._1+"'"
          }else{
    
    
            sql = "insert into wordcount (titleName,count) values ('" + word._1 + "','" + totalcount + "')"
          }

          conn.prepareStatement(sql).executeUpdate()
          println("保存结束--------------------------------------------------------------")
        } finally {
    
    
          conn.close()
        }
      })
    })

    ssc.start()
    ssc.awaitTermination()
  }
}