播放ANORM和SQL連接

Question

播放2.0 Scala中與ANORM框架提供了兩種方法來與數據庫進行交互：

def withConnection[A](name: String)(block: Connection => A): A = { 
    val connection = new AutoCleanConnection(getConnection(name)) 
    try { 
     block(connection) 
    } finally { 
     connection.close() 
    } 
    } 

    /** 
    * Execute a block of code, in the scope of a JDBC transaction. 
    * The connection and all created statements are automatically released. 
    * The transaction is automatically committed, unless an exception occurs. 
    * 
    * @param name The datasource name. 
    * @param block Code block to execute. 
    */ 
    def withTransaction[A](name: String)(block: Connection => A): A = { 
    withConnection(name) { connection => 
     try { 
     connection.setAutoCommit(false) 
     val r = block(connection) 
     connection.commit() 
     r 
     } catch { 
     case e => connection.rollback(); throw e 
     } 
    } 
    } 

現在很清楚，我說withConnection獲取和每次調用的時候關閉連接。

爲什麼兩種方法每次都創建和關閉連接？這不是一個昂貴的過程？

Answer 1

em ...因爲我們可以從連接池中檢索連接，所以沒有問題。 so close（）方法只是返回到池的連接，而不是實際關閉。