使用idea开发scala代码，使用spark从postgresql读取数据并转换成新的数据存入postgresql

libraryDependencies ++= Seq(
  "org.apache.spark" %% "spark-core" % "3.0.1",
  "org.apache.spark" %% "spark-sql" % "3.0.1",
  "org.postgresql" % "postgresql" % "42.2.18"
)

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

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

    val pgUrl = "jdbc:postgresql://host:port/database"
    val pgTable = "source_table"
    val pgProperties = new java.util.Properties()
    pgProperties.setProperty("user", "username")
    pgProperties.setProperty("password", "password")

    // 读取PostgreSQL数据
    val df: DataFrame = spark.read
      .format("jdbc")
      .option("url", pgUrl)
      .option("dbtable", pgTable)
      .option("properties", pgProperties)
      .load()

    // 数据转换示例：这里以转换为只取某些列为例
    val transformedDf = df.select("column1", "column2")

    // 定义存储数据的PostgreSQL信息
    val pgUrlWrite = "jdbc:postgresql://host:port/database"
    val pgTableWrite = "target_table"
    val pgPropertiesWrite = new java.util.Properties()
    pgPropertiesWrite.setProperty("user", "username")
    pgPropertiesWrite.setProperty("password", "password")
    pgPropertiesWrite.setProperty("driver", "org.postgresql.Driver")

    // 将转换后的数据写入新的PostgreSQL表
    transformedDf.write
      .mode("overwrite")
      .option("url", pgUrlWrite)
      .option("dbtable", pgTableWrite)
      .option("properties", pgPropertiesWrite)
      .format("jdbc")
      .save()

    spark.stop()
  }
}