servlet中获取配置文件中的参数.

servlet中获取配置文件中的参数.

 

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>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 log

43         // Put your code here

44     }

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 server

52      * @param response the response send by the server to the client

53      * @throws ServletException if an error occurred

54      * @throws IOException if an error occurred

55      */

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 server

68      * @param response the response send by the server to the client

69      * @throws ServletException if an error occurred

70      * @throws IOException if an error occurred

71      */

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 occurs

93      */

94     public void init() throws ServletException {        

95         this.setUsername(this.getInitParameter("username"));

96         this.setPassword(this.getInitParameter("password"));

97     }

98 

99 }

 

你可能感兴趣的:(servlet)