五、ServletConfig

一、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。

二、使用：

获取ServletConfig对象：

获取ServletConfig对象：ServletConfig sg = this.getServletConfig();

获取web.xml中的属性配置：sg.getInitParameter(name)

 1 public class TestServletConfig extends HttpServlet {
 2     @Override    
 3     protected void service(HttpServletRequest req, HttpServletResponse resp)
 4             throws ServletException, IOException {
 5         //获取ServletConfig对象
 6             ServletConfig sg = this.getServletConfig();
 7         //设置请求编码格式
 8             req.setCharacterEncoding(sg.getInitParameter("code"));
 9         //设置响应编码格式
10             resp.setContentType("text/html;charset=utf-8");
11         //获取请求信息
12             //获取web.xml中的属性配置
13             String flag = sg.getInitParameter("flag");
14             System.out.println(flag);
15             //获取用户请求信息
16             String uname=req.getParameter("uname");
17         //处理请求信息
18             System.out.println(uname);
19         //响应处理结果
20     }
21 }

web.xml中servlet的配置信息

 1 <?xml version="1.0" encoding="UTF-8"?>
 2 <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">
 3   <display-name>11-ServletConfig</display-name>
 4   <servlet>
 5     <description>This is the description of my J2EE component</description>
 6     <display-name>This is the display name of my J2EE component</display-name>
 7     <servlet-name>TestServletConfig</servlet-name>
 8     <servlet-class>com.bjsxt.servlet.TestServletConfig</servlet-class>
 9     <!-- 配置当前Servlet的属性信息 -->
10     <init-param>
11         <param-name>flag</param-name>
12         <param-value>true</param-value>
13     </init-param>
14      <init-param>
15         <param-name>code</param-name>
16         <param-value>utf-8</param-value>
17     </init-param>
18   </servlet>
19 
20   <servlet-mapping>
21     <servlet-name>TestServletConfig</servlet-name>
22     <url-pattern>/tg</url-pattern>
23   </servlet-mapping>
24 
25 </web-app>