1. 获取初始化参数
在web.xml中配置Servlet时，可以配置一些初始化参数。而在Servlet中可以通过ServletConfig接口提供的方法来取得这些参数。
index.jsp
1 <%@ page language="java" import="java.util.*" contentType="text/html; charset=UTF-8"%> 2 <% 3 String path = request.getContextPath(); 4 String basePath = request.getScheme()+"://"+request.getServerName()+":"+request.getServerPort()+path+"/"; 5 %> 6 7 <!DOCTYPE HTML PUBLIC "-//W3C//DTD HTML 4.01 Transitional//EN"> 8 <html> 9 <head> 10 <base href="<%=basePath%>"> 11 12 <title>My JSP ‘index.jsp‘ starting page</title> 13 <meta http-equiv="pragma" content="no-cache"> 14 <meta http-equiv="cache-control" content="no-cache"> 15 <meta http-equiv="expires" content="0"> 16 <meta http-equiv="keywords" content="keyword1,keyword2,keyword3"> 17 <meta http-equiv="description" content="This is my page"> 18 <!-- 19 <link rel="stylesheet" type="text/css" href="styles.css"> 20 --> 21 </head> 22 23 <body> 24 <h1>获取初始化参数演示案例</h1> 25 <hr> 26 <a href = "servlet/GetInitParam">获取初始化参数</a> 27 </body> 28 </html>
web.xml
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 <servlet-name>GetInitParam</servlet-name> 10 <servlet-class>servlet.GetInitParam</servlet-class> 11 <init-param> 12 <param-name>username</param-name> 13 <param-value>admin</param-value> 14 </init-param> 15 <init-param> 16 <param-name>password</param-name> 17 <param-value>123456</param-value> 18 </init-param> 19 </servlet> 20 21 <servlet-mapping> 22 <servlet-name>GetInitParam</servlet-name> 23 <url-pattern>/servlet/GetInitParam</url-pattern> 24 </servlet-mapping> 25 <welcome-file-list> 26 <welcome-file>index.jsp</welcome-file> 27 </welcome-file-list> 28 </web-app>
GetInitParam.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 GetInitParam extends HttpServlet {
12
13 private String username; // 用户名
14 private String password; // 密码
15
16 public String getUsername() {
17 return username;
18 }
19
20 public void setUsername(String username) {
21 this.username = username;
22 }
23
24 public String getPassword() {
25 return password;
26 }
27
28 public void setPassword(String password) {
29 this.password = password;
30 }
31
32 /**
33 * The doGet method of the servlet. <br>
34 *
35 * This method is called when a form has its tag value method equals to get.
36 *
37 * @param request the request send by the client to the server
38 * @param response the response send by the server to the client
39 * @throws ServletException if an error occurred
40 * @throws IOException if an error occurred
41 */
42 public void doGet(HttpServletRequest request, HttpServletResponse response)
43 throws ServletException, IOException {
44
45 doPost(request, response);
46 }
47
48 /**
49 * The doPost method of the servlet. <br>
50 *
51 * This method is called when a form has its tag value method equals to post.
52 *
53 * @param request the request send by the client to the server
54 * @param response the response send by the server to the client
55 * @throws ServletException if an error occurred
56 * @throws IOException if an error occurred
57 */
58 public void doPost(HttpServletRequest request, HttpServletResponse response)
59 throws ServletException, IOException {
60
61 response.setContentType("text/html; charset=UTF-8");
62 PrintWriter out = response.getWriter();
63 out.println("<!DOCTYPE HTML PUBLIC \"-//W3C//DTD HTML 4.01 Transitional//EN\">");
64 out.println("<HTML>");
65 out.println(" <HEAD><TITLE>A Servlet</TITLE></HEAD>");
66 out.println(" <BODY>");
67 out.println(" <h2>账号：" + this.getUsername() + "</h2>");
68 out.println(" <h2>密码：" + this.getPassword() + "</h2>");
69 out.println(" </BODY>");
70 out.println("</HTML>");
71 out.flush();
72 out.close();
73 }
74
75 public void init() throws ServletException {
76 this.setUsername(this.getInitParameter("username"));
77 this.setPassword(this.getInitParameter("password"));
78 }
79 }
2. MVC设计模式
3. Model2简介
4. 阶段项目
时间： 2024-08-05 15:33:43