Java web获得应用初始化参数

Bertha 。 2023-06-19 09:36 2阅读 0赞

Java 的代码

package com.my.servlet;
 
 import java.io.IOException;
 import java.io.PrintWriter;
 import java.util.Enumeration;
 
 import javax.servlet.ServletConfig;
 import javax.servlet.ServletException;
 import javax.servlet.annotation.WebServlet;
 import javax.servlet.http.HttpServlet;
 import javax.servlet.http.HttpServletRequest;
 import javax.servlet.http.HttpServletResponse;
 
 /**
 * Servlet implementation class HelloServlet
 */
 @WebServlet("/HelloServlet")
 public class HelloServlet extends HttpServlet {
 	private static final long serialVersionUID = 1L;
 
 	
 	/**
 * @see HttpServlet#HttpServlet()
 */
 public HelloServlet() {
 super();
 }
 public void init(ServletConfig config) throws ServletException{
 	super.init(config);
 	System.out.println(this.getClass().getName()+"的init方法被调用:");
 	
 }
 
 public void destroy() {
 	System.out.println(this.getClass().getName()+"的destory方法被调用");
 }
 	/**
 	 * @see HttpServlet#doGet(HttpServletRequest request, HttpServletResponse response)
 	 */
 	protected void doGet(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException {
 		response.setContentType("text/html;charset=UTF-8");
 		Enumeration<String> paraNames = super.getServletContext().getInitParameterNames();
 		String webSite = super.getServletContext().getInitParameter("webSite");
 		String adminEmail = super.getServletContext().getInitParameter("adminEmail");
 		PrintWriter out = response.getWriter();
 		out.print("所有初始化参数");
 		while(paraNames.hasMoreElements()) {
 			String name = paraNames.nextElement();
 			out.print(name+" ");
 		}
 		out.println("website的值："+webSite);
 		out.println("admail的值："+adminEmail+"");
 		out.flush();
 		out.close();
 	}
 	/**
 	 * @see HttpServlet#doPost(HttpServletRequest request, HttpServletResponse response)
 	 */
 	protected void doPost(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException {
 	}
 
 }

xml文件：

<?xml version="1.0" encoding="UTF-8"?>
 <web-app xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance" 
 xmlns="http://xmlns.jcp.org/xml/ns/javaee" 
 xsi:schemaLocation="http://xmlns.jcp.org/xml/ns/javaee http://xmlns.jcp.org/xml/ns/javaee/web-app_4_0.xsd" 
 id="WebApp_ID" version="4.0">
 <display-name>mytest2</display-name>
 <context-param>
 	 <param-name>webSite</param-name>
 	 <param-value>www.itshixun.com</param-value>
 </context-param>
 
 <context-param>
 	 <param-name>adminEmail</param-name>
 	 <param-value>gaohuqun@qq.com</param-value>
 </context-param>
 
 
 <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>
 	<servlet-name>HelloServlet</servlet-name>
 	<servlet-class>com.my.servlet.HelloServlet</servlet-class>
 	<init-param>
 		<param-name>url</param-name> 
 		<param-value>ifyouwannago</param-value>
 	</init-param> 
 	<init-param>
 		<param-name>user</param-name>
 		<param-value>qst</param-value>
 	</init-param>
 	<init-param>
 		<param-name>password</param-name>
 		<param-value>qst123</param-value>
 	</init-param>
 </servlet>
 
 <servlet-mapping>
 	<servlet-name>HelloServlet</servlet-name>
 	<url-pattern>/</url-pattern>
 </servlet-mapping>
 
 </web-app>