scala 封装jdbc的常用操作，自动关闭数据库的连接资源

Scala中貌似没有try-with的概念，在Java中则可以使用try-with自动释放连接资源，如：输入输出流、数据库连接。
在Scala中如果想要实现自动释放数据库的连接资源时，需要自己封装。借鉴网上大神的博客，给大家分享一下我自己的Scala jdbc操作工具类。

case class CloseAble[A <: {def close() : Unit}](a: A) {
  def map[B](f: A => B): B =
    try f(a)
    finally {
      if (a != null){
        a.close()
      }
    }

  def flatMap[B](f: A => B): B = map(f)
}

初始化数据库连接对象

  private def initConnection(): Unit = {
    try {
      Class.forName(this._driverClassName).newInstance()
      this.conn = DriverManager.getConnection(this._url, this._user, this._password)
    } catch {
      case e: Exception => {
        e.printStackTrace()
      }
    }
  }

查询模型函数

 def queryModel[A](sql: String)(implicit f: ResultSet => List[A]): List[A] = {
    initConnection()
    CloseAble(this.conn).flatMap {
      conn =>CloseAble(conn.prepareStatement(sql, ResultSet.TYPE_FORWARD_ONLY, ResultSet.CONCUR_READ_ONLY))
          .flatMap {
            stmt =>CloseAble(stmt.executeQuery()).map {
                rs => f(rs)
              }
          }
    }
  }

测试

object Test {


  implicit def f1(rs: ResultSet): List[Int] = {
    val data: ListBuffer[Int] = ListBuffer()
    while (rs.next()) {
      data.append(rs.getInt("id"))
    }
    return data.toList
  }

  def main(args: Array[String]): Unit = {
    val dbHelper = RelationDbHelper()
    for (i <- 1 to 1000) {
      val data = dbHelper.queryModel[Int]("select * from etl_new_banner_store")(f1)
      println(i)
      println(data)
    }
  }
}

感谢大神[吐思圈] https://www.jianshu.com/u/a019e1b214c9
https://www.jianshu.com/p/fbd3cd650fe9