WEB-ServletConfig与ServletContext

import java.io.IOException;

import javax.servlet.Servlet;
import javax.servlet.ServletConfig;
import javax.servlet.ServletContext;
import javax.servlet.ServletException;
import javax.servlet.ServletRequest;
import javax.servlet.ServletResponse;

public class HelloServlet implements Servlet {
	private ServletConfig servletConfig;
	@Override
	public void destroy() {
		// TODO Auto-generated method stub
		
	}

	@Override
	public ServletConfig getServletConfig() {
		// TODO Auto-generated method stub
		return null;
	}

	@Override
	public String getServletInfo() {
		// TODO Auto-generated method stub
		return null;
	}

	@Override
	public void init(ServletConfig arg0) throws ServletException {
		// TODO Auto-generated method stub
		this.servletConfig = arg0;
	}

	@Override
	public void service(ServletRequest arg0, ServletResponse arg1) throws ServletException, IOException {
		// TODO Auto-generated method stub
		System.out.println("hello");
		String initParameter = servletConfig.getInitParameter("encode");
		System.out.println("initParameter:"+initParameter);
		ServletContext servletContext = servletConfig.getServletContext();
		System.out.println("servletContext:"+servletContext);
		String servletName = servletConfig.getServletName();
		System.out.println("servletName:"+servletName);
		
		String initParameter2 = servletContext.getInitParameter("age");
		System.out.println("initParameter2:"+initParameter2);
		String realPath = servletContext.getRealPath("login.htli");
		System.out.println("realPath:"+realPath);
		
		
	}

}

<?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">
 	<!-- 
 		注册
 			1.加载类全路径
 			2.url
 			
 			
 		两个<servlet-name>名字需要对应好，一般为Servlet的文件名
 	 -->
 	 <context-param>
 	 	<param-name>age</param-name>
 	 	<param-value>18</param-value>
 	 </context-param>
 	 <servlet>
 	 	<servlet-name>HelloServlet</servlet-name>
 	 	<servlet-class>com.atguigu.servlet.HelloServlet</servlet-class>
 	 	
 	 	<init-param>
 	 		<param-name>encode</param-name>
 	 		<param-value>UTF-8</param-value>
 	 	</init-param>	
 	 	
 	 </servlet>
 	 <servlet-mapping>
 	 	<servlet-name>HelloServlet</servlet-name>
 	 	<url-pattern>/HelloServlet</url-pattern>
 	 </servlet-mapping>
</web-app>