Java 使用 servletContextListener 将属性文件值加载到 web.xml 中

loading the property file values into web.xml using servletContextListener

提问by user2567005

i want load the values form property file in to my web.xml

我想将值表单属性文件加载到我的 web.xml

this is my web.xml file

这是我的 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">


    <!-- Property listeners -->
    <listener>       
      <listener-class>com.kpowd.utility.PropertyReading</listener-class>
   </listener>  

    <display-name>JSF 2 + Spring 3 Integration example</display-name>
    <!-- The welcome page -->
    <welcome-file-list>
        <welcome-file>login.xhtml</welcome-file>
    </welcome-file-list>

    <!-- Spring listeners -->
    <listener>
        <listener-class>org.springframework.web.context.ContextLoaderListener</listener-class>
    </listener>
    <listener>
        <listener-class>
            org.springframework.web.context.request.RequestContextListener</listener-class>
    </listener>

    <context-param>
        <param-name>contextConfigLocation</param-name>
        <param-value>
            /WEB-INF/spring-security.xml,
            /WEB-INF/applicationContext.xml            
        </param-value>
    </context-param>
    <!-- Change the primeface theme -->

    <context-param>
        <param-name>primefaces.THEME</param-name>
        <param-value>${primefacestheme}</param-value>
    </context-param>

    <!-- Spring Security -->
    <filter>
        <filter-name>springSecurityFilterChain</filter-name>
        <filter-class>org.springframework.web.filter.DelegatingFilterProxy</filter-class>
    </filter>

    <filter-mapping>
        <filter-name>springSecurityFilterChain</filter-name>
        <url-pattern>/*</url-pattern>
    </filter-mapping>

    <!-- Start JSF -->
    <servlet>
        <servlet-name>Faces Servlet</servlet-name>
        <servlet-class>javax.faces.webapp.FacesServlet</servlet-class>
        <load-on-startup>1</load-on-startup>
    </servlet>

    <!-- JSF URL mapping -->
    <servlet-mapping>
        <servlet-name>Faces Servlet</servlet-name>
        <url-pattern>*.xhtml</url-pattern>
    </servlet-mapping>

</web-app>

and this is my servelet context listner class

这是我的小服务器上下文监听器类

package com.kpowd.utility;

import java.io.IOException;
import java.util.Properties;

import javax.servlet.ServletContextEvent;
import javax.servlet.ServletContextListener;

public class PropertyReading implements ServletContextListener {

    @Override
    public void contextDestroyed(ServletContextEvent event) {
        // TODO Auto-generated method stub

    }

    @Override
    public void contextInitialized(ServletContextEvent event) {

        final String props = "/config.properties";
        final Properties propsFromFile = new Properties();
        try {               
            propsFromFile.load(getClass().getResourceAsStream(props));

        } catch (final IOException e) {
            e.printStackTrace();
        }
        for (String prop : propsFromFile.stringPropertyNames())
          {
             if (System.getProperty(prop) == null)
             {
                 System.setProperty(prop, propsFromFile.getProperty(prop));
             }
          }

    }

}

when i print the values form this class it shows me the proprety values but in web.xml when im trying to access ${primefacestheme} this value it doesn't load

当我从此类打印值时，它向我显示了属性值，但在 web.xml 中，当我尝试访问 ${primefacestheme} 时，它不会加载此值

and this is my config.properties file

这是我的 config.properties 文件

primefacestheme=glass-x
wellcomepage=accdenied.xhtml

please help me

请帮我

采纳答案by Amogh

Can you check with change in web.xml:

您可以检查 web.xml 中的更改：

<context-param>
   <param-name>primefacestheme</param-name> 
   <param-value>${primefacestheme}</param-value>
</context-param>

As config.propertieshaving property key name as primefacesthemeand in code we are checking with that key name and if its nullthen setting property value to that key name.

由于在代码中config.properties具有属性键名称，primefacestheme我们正在检查该键名称以及是否null将属性值设置为该键名称。

In short <param-name>and property key name need to be same.

简而言之<param-name>，属性键名称需要相同。

回答by SparkOn

As your properties file contains the key as primefacesthemebut while calling its value you are trying to use some other key

由于您的属性文件包含键，primefacestheme但在调用其值时，您正尝试使用其他键

change this

改变这个

<context-param>
  <param-name>primefaces.THEME</param-name>
  <param-value>${primefacestheme}</param-value>
</context-param>

to

到

<context-param>
  <param-name>primefacestheme</param-name>
  <param-value>${primefacestheme}</param-value>
</context-param>