Servlet--ServletContext(三)获取web.xml配置参数

   

    

     

      

     
     

      

       package test07_3context;
      
     
    

     

      

     
     

      
 
      
     
    

     

      

     
     

      

       import java.io.IOException;
      
     
    

     

      

     
     

      

       import java.io.PrintWriter;
      
     
    

     

      

     
     

      

       import java.util.Enumeration;
      
     
    

     

      

     
     

      
 
      
     
    

     

      

     
     

      

       import javax.servlet.ServletContext;
      
     
    

     

      

     
     

      

       import javax.servlet.ServletException;
      
     
    

     

      

     
     

      

       import javax.servlet.http.HttpServlet;
      
     
    

     

      

     
     

      

       import javax.servlet.http.HttpServletRequest;
      
     
    

     

      

     
     

      

       import javax.servlet.http.HttpServletResponse;
      
     
    

     

      

     
     

      
 
      
     
    

     

      

     
     

      

       public class WebServlet extends HttpServlet {
      
     
    

     

      

     
     

      
 
      
     
    

     

      

     
     

      
	@Override
      
     
    

     

      

     
     

      
	public void init() throws ServletException {
      
     
    

     

      

     
     

      
		// TODO Auto-generated method stub
      
     
    

     

      

     
     

      

       		System.out.println("=========在控制台输出Web配置信息=========");
      
     
    

     

      

     
     

      
		
      
     
    

     

      

     
     

      
		//获取ServletContext
      
     
    

     

      

     
     

      
		ServletContext app = getServletContext();
      
     
    

     

      

     
     

      
		//获取web配置的信息
      
     
    

     

      

     
     

      

       		System.out.println("①、通过参数名称获取Web配置的信息");
      
     
    

     

      

     
     

      
		String names = app.getInitParameter("name");
      
     
    

     

      

     
     

      

       		System.out.println("name的值："+names);
      
     
    

     

      

     
     

      
		String ages = app.getInitParameter("age");
      
     
    

     

      

     
     

      

       		System.out.println("age的值："+ages);
      
     
    

     

      

     
     

      

       		System.out.println("--------------------");
      
     
    

     

      

     
     

      
		//通过遍历方式获取web配置的信息
      
     
    

     

      

     
     

      

       		System.out.println("②、通过Enumration遍历方式获取web配置的信息");
      
     
    

     

      

     
     

      

       		Enumeration<String> en = app.getInitParameterNames();
      
     
    

     

      

     
     

      
		while(en.hasMoreElements()){
      
     
    

     

      

     
     

      
			String key = en.nextElement();
      
     
    

     

      

     
     

      

       			System.out.println("key的值为："+app.getInitParameter(key));
      
     
    

     

      

     
     

      

       		}
      
     
    

     

      

     
     

      
		
      
     
    

     

      

     
     

      

       	}
      
     
    

     

      

     
     

      
	public void doGet(HttpServletRequest request, HttpServletResponse response)
      
     
    

     

      

     
     

      
			throws ServletException, IOException {
      
     
    

     

      

     
     

      
 
      
     
    

     

      

     
     

      

       		response.setContentType("text/html;charset=UTF-8");
      
     
    

     

      

     
     

      
		PrintWriter out = response.getWriter();
      
     
    

     

      

     
     

      

       		out.println("===========在网页输出Web配置信息==========="+"<br/>");
      
     
    

     

      

     
     

      
		
      
     
    

     

      

     
     

      

       		out.println("①、通过参数名称获取Web配置的信息"+"<br/>");
      
     
    

     

      

     
     

      
		
      
     
    

     

      

     
     

      
		ServletContext ap = getServletContext();
      
     
    

     

      

     
     

      
		String nm = ap.getInitParameter("name");
      
     
    

     

      

     
     

      

       		out.print("name的值："+nm+"<br/>");
      
     
    

     

      

     
     

      
		String ag = ap.getInitParameter("age");
      
     
    

     

      

     
     

      

       		out.print("age的值："+ag+"<br/>");
      
     
    

     

      

     
     

      
		
      
     
    

     

      

     
     

      

       		out.println("②、通过Enumration遍历方式获取web配置的信息"+"<br/>");
      
     
    

     

      

     
     

      

       		Enumeration<String> eu = ap.getInitParameterNames();
      
     
    

     

      

     
     

      
		while(eu.hasMoreElements()){
      
     
    

     

      

     
     

      
			String ke = eu.nextElement();
      
     
    

     

      

     
     

      

       			out.print("key的值为："+ap.getInitParameter(ke)+"<br/>");
      
     
    

     

      

     
     

      

       		}
      
     
    

     

      

     
     

      
		
      
     
    

     

      

     
     

      

       	}
      
     
    

     

      

     
     

      
 
      
     
    

     

      

     
     

      

       }
      
     
   
  

   

    

     

      

     
     

      

       <?xml version="1.0" encoding="UTF-8"?>
      
     
    

     

      

     
     

      

       <web-app version="3.0"
      
     
    

     

      

     
     

      
    xmlns="http://java.sun.com/xml/ns/javaee"
      
     
    

     

      

     
     

      
    xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
      
     
    

     

      

     
     

      
    xsi:schemaLocation="http://java.sun.com/xml/ns/javaee http://java.sun.com/xml/ns/javaee/web-app_3_0.xsd">
      
     
   
  

   

    

     

      

     
     

      

        <!-- servletContext获取web配置的参数如下有name和age两个参数 -->
      
     
    

     

      

     
     

      
 <context-param>
      
     
    

     

      

     
     

      
 	<param-name>name</param-name>
      
     
    

     

      

     
     

      
 	<param-value>我的家乡在中国</param-value>
      
     
    

     

      

     
     

      
 </context-param>
      
     
    

     

      

     
     

      
 <context-param>
      
     
    

     

      

     
     

      
 	<param-name>age</param-name>
      
     
    

     

      

     
     

      
 	<param-value>65</param-value>
      
     
    

     

      

     
     

      
 </context-param>
      
     
    

     

      

     
     

      
 <servlet>
      
     
    

     

      

     
     

      
    <description>This is the description of my J2EE component</description>
      
     
    

     

      

     
     

      
    <display-name>This is the display name of my J2EE component</display-name>
      
     
    

     

      

     
     

      
    <servlet-name>WebServlet</servlet-name>
      
     
    

     

      

     
     

      
    <servlet-class>test07_3context.WebServlet</servlet-class>
      
     
    

     

      

     
     

      
    <load-on-startup>1</load-on-startup>
      
     
    

     

      

     
     

      
  </servlet>
      
     
    

     

      

     
     

      
 
      
     
    

     

      

     
     

      
  <servlet-mapping>
      
     
    

     

      

     
     

      
    <servlet-name>WebServlet</servlet-name>
      
     
    

     

      

     
     

      
    <url-pattern>/WebServlet</url-pattern>
      
     
    

     

      

     
     

      
  </servlet-mapping>
      
     
    

     

      

     
     

      
 
      
     
    

     

      

     
     

      

       </web-app>