web.xml (添加init-param)
1 <?xml version="1.0" encoding="UTF-8"?> 2 <web-app version="2.5" 3 xmlns="http://java.sun.com/xml/ns/javaee" 4 xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance" 5 xsi:schemaLocation="http://java.sun.com/xml/ns/javaee 6 http://java.sun.com/xml/ns/javaee/web-app_2_5.xsd"> 7 <display-name></display-name> 8 <servlet> 9 <description>This is the description of my J2EE component</description>10 <display-name>This is the display name of my J2EE component</display-name>11 <servlet-name>GetInitParameterServlet</servlet-name>12 <servlet-class>servlet.GetInitParameterServlet</servlet-class>13 <init-param>14 <param-name>username</param-name>15 <param-value>admin</param-value>16 </init-param>17 <init-param>18 <param-name>passWord</param-name>19 <param-value>123456</param-value>20 </init-param>21 </servlet>22 23 <servlet-mapping>24 <servlet-name>GetInitParameterServlet</servlet-name>25 <url-pattern>/servlet/GetInitParameterServlet</url-pattern>26 </servlet-mapping> 27 <welcome-file-list>28 <welcome-file>index.jsp</welcome-file>29 </welcome-file-list>30 </web-app>
index.jsp
1 <h1>獲取初始化參數演示案例</h1>2 <hr>3 <a href="servlet/GetInitParameterServlet">獲取初始化Servlet</a>
GetInitParameterServlet.java:
1 package servlet; 2 3 import java.io.IOException; 4 import java.io.PRintWriter; 5 6 import javax.servlet.ServletException; 7 import javax.servlet.http.HttpServlet; 8 import javax.servlet.http.HttpServletRequest; 9 import javax.servlet.http.HttpServletResponse;10 11 public class GetInitParameterServlet extends HttpServlet {12 private String username;13 private String password; 14 15 public String getUsername() {16 return username;17 }18 19 public void setUsername(String username) {20 this.username = username;21 }22 23 public String getPassword() {24 return password;25 }26 27 public void setPassword(String password) {28 this.password = password;29 }30 31 /**32 * Constructor of the object.33 */34 public GetInitParameterServlet() {35 super();36 }37 38 /**39 * Destruction of the servlet. <br>40 */41 public void destroy() {42 super.destroy(); // Just puts "destroy" string in log43 // Put your code here44 }45 46 /**47 * The doGet method of the servlet. <br>48 *49 * This method is called when a form has its tag value method equals to get.50 * 51 * @param request the request send by the client to the server52 * @param response the response send by the server to the client53 * @throws ServletException if an error occurred54 * @throws IOException if an error occurred55 */56 public void doGet(HttpServletRequest request, HttpServletResponse response)57 throws ServletException, IOException {58 59 doPost(request, response);60 }61 62 /**63 * The doPost method of the servlet. <br>64 *65 * This method is called when a form has its tag value method equals to post.66 * 67 * @param request the request send by the client to the server68 * @param response the response send by the server to the client69 * @throws ServletException if an error occurred70 * @throws IOException if an error occurred71 */72 public void doPost(HttpServletRequest request, HttpServletResponse response)73 throws ServletException, IOException {74 75 response.setContentType("text/html;charset=utf-8");76 PrintWriter out = response.getWriter();77 out.println("<!DOCTYPE HTML PUBLIC /"-//W3C//DTD HTML 4.01 Transitional//EN/">");78 out.println("<HTML>");79 out.println(" <HEAD><TITLE>A Servlet</TITLE></HEAD>");80 out.println(" <BODY>");81 out.println("<h2>用戶名:"+this.getUsername()+"</h2>");82 out.println("<h2>密碼:"+this.getPassword()+"</h2>");83 out.println(" </BODY>");84 out.println("</HTML>");85 out.flush();86 out.close();87 }88 89 /**90 * Initialization of the servlet. <br>91 *92 * @throws ServletException if an error occurs93 */94 public void init() throws ServletException { 95 this.setUsername(this.getInitParameter("username"));96 this.setPassword(this.getInitParameter("password"));97 }98 99 }
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