ServletConfig的使用

深碍√TFBOYSˉ_ 2021-12-17 13:15 272阅读 0赞

## ServletConfig的使用 ##

**作用**  
ServletConfig 对象是 Servlet 的专属配置对象， 每个 Servlet 都单独拥有一个ServletConfig 对象， 用来获取 web.xml 中的配置信息。  
**使用**

*  获取 ServletConfig 对象
 *  获取 web.xml 中 servlet 的配置信息

**示例**

![在这里插入图片描述][watermark_type_ZmFuZ3poZW5naGVpdGk_shadow_10_text_aHR0cHM6Ly9ibG9nLmNzZG4ubmV0L3dlaXhpbl80MzE1NTg2Ng_size_16_color_FFFFFF_t_70]  
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" 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>07-ServletConfig</display-name>
      <welcome-file-list>
        <welcome-file>index.html</welcome-file>
        <welcome-file>index.htm</welcome-file>
        <welcome-file>index.jsp</welcome-file>
        <welcome-file>default.html</welcome-file>
        <welcome-file>default.htm</welcome-file>
        <welcome-file>default.jsp</welcome-file>
      </welcome-file-list>
      <servlet>
        <description></description>
        <display-name>sg</display-name>
        <servlet-name>sg</servlet-name>
        <servlet-class>com.wf.servlet.ServletConfigServlet</servlet-class>
        <init-param>
        	<param-name>config</param-name>
        	<param-value>utf-8</param-value>
        </init-param>
      </servlet>
      <servlet-mapping>
        <servlet-name>sg</servlet-name>
        <url-pattern>/sg</url-pattern>
      </servlet-mapping>
    </web-app>

Servlet文件

package com.wf.servlet;
    
    import java.io.IOException;
    
    import javax.servlet.ServletConfig;
    import javax.servlet.ServletException;
    import javax.servlet.http.HttpServlet;
    import javax.servlet.http.HttpServletRequest;
    import javax.servlet.http.HttpServletResponse;
    
    /** * ServletConfig对象学习 * @ClassName ServletConfigServlet * @Description * @Author Wangfei * @Date 2019年7月8日 下午7:53:34 */
    
    public class ServletConfigServlet extends HttpServlet { 
    	@Override
    	protected void service(HttpServletRequest req, HttpServletResponse resp) 
    			throws ServletException, IOException { 
    		//获取ServletConfig对象
    		ServletConfig servletConfig = this.getServletConfig();
    		//获取web.xml中的配置数据
    		String initParameter = servletConfig.getInitParameter("config");
    		System.out.println(initParameter);
    	}
    }

运行结果  
![在这里插入图片描述][watermark_type_ZmFuZ3poZW5naGVpdGk_shadow_10_text_aHR0cHM6Ly9ibG9nLmNzZG4ubmV0L3dlaXhpbl80MzE1NTg2Ng_size_16_color_FFFFFF_t_70 1]

[watermark_type_ZmFuZ3poZW5naGVpdGk_shadow_10_text_aHR0cHM6Ly9ibG9nLmNzZG4ubmV0L3dlaXhpbl80MzE1NTg2Ng_size_16_color_FFFFFF_t_70]: /images/20211213/98feee4ec881447cb4389c4e432cdc14.png
[watermark_type_ZmFuZ3poZW5naGVpdGk_shadow_10_text_aHR0cHM6Ly9ibG9nLmNzZG4ubmV0L3dlaXhpbl80MzE1NTg2Ng_size_16_color_FFFFFF_t_70 1]: /images/20211213/a37aeb9a711b445b986c2a4de9d9f93a.png