J2EE 程序员一般都有现成的应用服务器所带的JDBC 数据库连接池，不过对于开发一般的 Java Application 、 Applet 或者 JSP、velocity 时，我们可用的JDBC 数据库连接池并不多，并且一般性能都不好。我们可以自己写一个JDBC 数据库连接池。-J2EE programmers tend to have a ready-made application server release the JDBC database connection pool, but for the general development of the Java Application, applet or JSP, velocity, we can use JDBC database connection pool is not over, and generally not a good performance. We ourselves wrote a JDBC database connection pool.