一个数据库连接池的完整代码，根据网上找来的代码改写。在jbuilder下测试完全通过 使用时注意修改properties文件。用于商业用途请与原开发者联系。原则上只用于学习目的-a database connection pool integrity code, according to the Internet brought the code rewritten. In JBuilder fully tested through the use of properties when changes to documents. For commercial purposes, please contact the original developers. In principle, only for the purpose of learning