java - Best way to use java sql connection

Question

What is the best way to use connection in java application that having around 100 classes. 1) When user logging to the system, create a connection and pass to other classes and close when user presses exit button. or, 2) create a connection within every method and close when method ends.(Methods like we use for get data from db)

Answer 1

标准的答案是使用连接池，它经常在连接过多和并发所需的连接数之间取得适当的平衡。看看http://docs.oracle.com/javase/7/docs/api/javax/sql/ConnectionPoolDataSource.html

Answer 2

一如既往，这取决于。您不能在 2013 年合法地打开数百万个数据库连接，这是一个性能问题。您要做的是缓存尽可能多的数据，以减少到数据库的往返次数。通常，您只希望在使用时打开连接，不需要打开幻像连接。