在Servlet外部检索Init参数

注册 ServletContextListener 以在服务器启动时加载Init参数。

加载属性并使它对其他类静态可见。

样例代码：

public class AppServletContextListener implements ServletContextListener {    private static Properties properties;    @Override    public void contextInitialized(ServletContextEvent servletContextEvent) {        String cfgfile = servletContextEvent.getServletContext().getInitParameter("config_file");        properties.load(new FileInputStream(cfgfile));        //Some pre..        properties.getProperty("dbUser");    }    public static Properties getProperties(){        return properties;    }}

web.xml：

<listener>    <listener-class>com.x.y.z.AppServletContextListener</listener-class></listener><context-param>      <param-name>config_file</param-name>      <param-value>config_file_location</param-value></context-param>