自定义监听器类来加载web.xml中的<context-param>系统属性</context-param> 和xxx.properties文件属性

1：配置web.xml文件

<?xml version="1.0" encoding="UTF-8"?><web-app xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance" xmlns="http://java.sun.com/xml/ns/javaee" xmlns:web="http://java.sun.com/xml/ns/javaee/web-app_2_5.xsd" xsi:schemaLocation="http://java.sun.com/xml/ns/javaee http://java.sun.com/xml/ns/javaee/web-app_2_5.xsd" id="WebApp_ID" version="2.5">  <display-name>SpringMVC</display-name>  <welcome-file-list>    <welcome-file>webpage/index.html</welcome-file>    <welcome-file>webpage/index.htm</welcome-file>    <welcome-file>webpage/index.jsp</welcome-file>    <welcome-file>webpage/default.html</welcome-file>    <welcome-file>webpage/default.htm</welcome-file>    <welcome-file>webpage/default.jsp</welcome-file>  </welcome-file-list>    <context-param>        <param-name>USERNAME</param-name>        <param-value>liufukin</param-value>    </context-param>    <listener>        <listener-class>system.InitListener</listener-class>    </listener>  <servlet>    <servlet-name>springmvc</servlet-name>    <servlet-class>org.springframework.web.servlet.DispatcherServlet</servlet-class>    <init-param>        <param-name>contextConfigLocation</param-name>        <param-value>/WEB-INF/classes/springAnnotation-mvc.xml</param-value>    </init-param>    <load-on-startup>1</load-on-startup>  </servlet>  <servlet-mapping>    <servlet-name>springmvc</servlet-name>    <url-pattern>*.do</url-pattern>  </servlet-mapping></web-app>

2：创建自定义监听器类InitListener来加载web.xml中的系统属性 和xxx.properties文件属性

package system;import javax.servlet.ServletContextEvent;import javax.servlet.ServletContextListener;import util.LoadProperties;/** * @author Kin.Liufu * @created 2016-1-25 * @describe  */public class InitListener implements ServletContextListener{    public void contextDestroyed(ServletContextEvent sce) {          System.out.println("web exit ... ");      }    @Override    public void contextInitialized(ServletContextEvent sce) {        System.out.println("system init .......");        //加载web.xml中的配置信息        System.out.println(sce.getServletContext().getInitParameter("USERNAME"));        //加载.properties配置文件的信息，但是需要LoadProperties这个静态类的支持        System.out.println(LoadProperties.getProperty("config.properties", "userPwd", "liufu"));    }}

3：加载xxx.properties属性文件需要LoadProperties的支持，所以就自己写了一个加载properties文件的工具类

import java.io.IOException;import java.io.InputStream;import java.util.Hashtable;import java.util.Locale;import java.util.Properties;import org.apache.log4j.Level;import org.apache.log4j.Logger;public class LoadProperties {    private static Logger loger = Logger.getLogger(LoadProperties.class);    private static Hashtable<String, Properties> htProp = new Hashtable<String, Properties>();    public static String getProperty(String properties, String key)            throws IOException {        Properties p = getProperties(properties);        return p.getProperty(key)!=null ? p.getProperty(key).trim() : null;    }    public static Properties getProperties(String properties)            throws IOException {        loger.info("start to read the properties file");        Properties p = (Properties) htProp.get(properties);        if (p == null) {            LoadProperties.retrieveKeyMap(properties);            p = (Properties) htProp.get(properties);            if (p == null) {                throw new IOException("Can't retrieve specified properties: "                        + properties);            }        }        loger.info("end to read the properties file");        return p;    }    public static String getProperty(String properties, String key, String defaultValue)    {        try{            Properties p = getProperties(properties);            return p.getProperty(key,defaultValue);        }        catch(Exception e)        {        }        return defaultValue;    }    public static String getProperty(String properties, String key,            Locale locale) throws IOException {        String langName = locale.toString();        return getProperty(properties, key + "_" + langName);    }    public static void refresh(String properties) throws IOException {        retrieveKeyMap(properties);    }    private static void retrieveKeyMap(String propertyFileName) throws IOException {        Properties p = new Properties();        InputStream is = LoadProperties.class.getResourceAsStream("/" + propertyFileName);        if (is == null) {            is = LoadProperties.class                    .getResourceAsStream(propertyFileName);            if (is == null) {                is = ClassLoader.getSystemResourceAsStream(                        propertyFileName);            }        }        if (is == null) {            loger.log(Level.INFO, "Resource file cannot be found: " + propertyFileName);        } else {            p.load(is); // throw IOException            is.close();            htProp.put(propertyFileName, p);        }    }}