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

来源：互联网发布：义乌美工学徒招聘编辑：程序博客网时间：2024/06/08 13:44

一、ServletContext作用之获取配置文件参数

1、获取配置文件实例：

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 {@Overridepublic void init() throws ServletException {// TODO Auto-generated method stubSystem.out.println("=========在控制台输出Web配置信息=========");//获取ServletContextServletContext 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/>");}}}

2、配置文件参数

<?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>

3、测试

启动该项目，在浏览器中输入测试地址：http://127.0.0.1:8080/test07_3/WebServlet

测试结果：

A、控制台结果：

B、网页端结果：

阅读全文

0 0