实例化Spring容器的两种常用方式
//在类路径下寻找配置文件来实例化容器
ApplicationContext ctx = new ClassPathXmlApplicationContext(new String[]{"beans.xml"});
//在类路径下寻找配置文件来实例化容器
ApplicationContext ctx = new FileSystemXmlApplicationContext(new String[]{"d:\\beans.xml"});