spark不支持。但是我已经用foreachpartition完成了（只使用dataframe数据…）
apachesparksql是否支持merge子句？

df.rdd.coalesce(2).foreachPartition(partition => {
  val connectionProperties = brConnect.value
  val jdbcUrl = connectionProperties.getProperty("jdbcurl")
  val user = connectionProperties.getProperty("user")
  val password = connectionProperties.getProperty("password")
  val driver = connectionProperties.getProperty("Driver")
  Class.forName(driver)
  val dbc: Connection = DriverManager.getConnection(jdbcUrl, user, password)
  val db_batchsize = 1000
  var pstmt: PreparedStatement = null
  partition.grouped(db_batchsize).foreach(batch => {
    batch.foreach{ row =>
      {
        val id = row.id
        val fname = row.fname
        val lname = row.lname
        val userid = row.userid
        println(id, fname)
        val sqlString = "INSERT employee USING   " +
        " values (?, ?, ?, ?) "

        var pstmt: PreparedStatement = dbc.prepareStatement(sqlString)
        pstmt.setLong(1, row.id)
        pstmt.setString(2, row.fname)
        pstmt.setString(3, row.lname)
        pstmt.setString(4, row.userid)
        pstmt.addBatch()
        pstmt.executeBatch()
      }
    }
    //pstmt.executeBatch()
    dbc.commit()
    pstmt.close()
  })
  dbc.close()
})