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[Java教程]servlet中获取配置文件中的参数.


 

web.

 1 <??> 2 <web-app version="2.5"  3   ="http://java.sun.com/  4   ="http://www.w3.org/2001/  5   xsi:schemaLocation="http://java.sun.com/ 6   http://java.sun.com/> 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>获取初始化参数演示案例</h1>2   <hr>3   <a href="servlet/GetInitParameterServlet">获取初始化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>用户名:"+this.getUsername()+"</h2>");82   out.println("<h2>密码:"+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 }