Servlet获取初始化参数

一获取初始化参数

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接口提供方法来取得这些参数。

二界面

<%@ page language = "java" import = "java.util.*" contentType = "text/html; charset=utf-8" %>

String path = request.getContextPath();

String basePath = request.getScheme()+ "://" +request.getServerName()+ ":" +request.getServerPort()+path+ "/" ;

<! DOCTYPE HTML PUBLIC "-//W3C//DTD HTML 4.01 Transitional//EN">

< html >

< head >

< base href = " <%= basePath %> " >

< title > My JSP 'index.jsp' starting page </ title >

< meta http-equiv = "pragma" content = "no-cache" >

< meta http-equiv = "cache-control" content = "no-cache" >

< meta http-equiv = "expires" content = "0" >

< meta http-equiv = "keywords" content = "keyword1,keyword2,keyword3" >

< meta http-equiv = "description" content = "This is my page" >

<!--

-->

</ head >

< body >

< h1 > 获取初始化参数演示案例 </ h1 >

< hr >

< a href = "servlet/GetInitParameterServlet" > 获取初始化参数 Servlet </ a >

</ body >

</ html >

三配置文件

<? xml version = "1.0" encoding = "UTF-8" ?>

< web-app xmlns:xsi = " http://www.w3.org/2001/XMLSchema-instance" ; xmlns = " http://java.sun.com/xml/ns/javaee" ; xmlns:web = " http://java.sun.com/xml/ns/javaee/web-app_2_5.xsd" ; xsi:schemaLocation = " http://java.sun.com/xml/ns/javaee http://java.sun.com/xml/ns/javaee/web-app_2_5.xsd" ; version = "2.5" >

< display-name ></ display-name >

< servlet >

< description > This is the description of my J2EE component </ description >

< display-name > This is the display name of my J2EE component </ display-name >

< servlet-name > GetInitParameterServlet </ servlet-name >

< servlet-class > servlet.GetInitParameterServlet </ servlet-class >

< init-param >

< param-name > username </ param-name >

< param-value > admin </ param-value >

</ init-param >

< init-param >

< param-name > password </ param-name >

< param-value > 123456 </ param-value >

</ init-param >

</ servlet >

< servlet-mapping >

< servlet-name > GetInitParameterServlet </ servlet-name >

< url-pattern > / servlet /GetInitParameterServlet </ url-pattern >

</ servlet-mapping >

< welcome-file-list >

< welcome-file > index.jsp </ welcome-file >

</ welcome-file-list >

</ web-app >

四 Servlet

package servlet;

import java.io.IOException;

import java.io.PrintWriter;

import javax.servlet.ServletException;

import javax.servlet.http.HttpServlet;

import javax.servlet.http.HttpServletRequest;

import javax.servlet.http.HttpServletResponse;

public class GetInitParameterServlet extends HttpServlet {

private String username;//用户名

private String password; //密码

public String getUsername() {

return username;

}

public void setUsername(String username) {

this.username = username;

}

public String getPassword() {

return password;

}

public void setPassword(String password) {

this.password = password;

}

/**

* Constructor of the object.

public GetInitParameterServlet() {

super();

}

/**

* Destruction of the servlet. <br>

public void destroy() {

super.destroy(); // Just puts "destroy" string in log

// Put your code here

}

/**

* The doGet method of the servlet. <br>

* This method is called when a form has its tag value method equals to get.

* @param request the request send by the client to the server

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

* @throws ServletException if an error occurred

* @throws IOException if an error occurred

public void doGet(HttpServletRequest request, HttpServletResponse response)

throws ServletException, IOException {

doPost(request,response);

}

/**

* The doPost method of the servlet. <br>

* This method is called when a form has its tag value method equals to post.

* @param request the request send by the client to the server

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

* @throws ServletException if an error occurred

* @throws IOException if an error occurred

public void doPost(HttpServletRequest request, HttpServletResponse response)

throws ServletException, IOException {

response.setContentType("text/html;charset=utf-8");

PrintWriter out = response.getWriter();

out.println("<!DOCTYPE HTML PUBLIC \"-//W3C//DTD HTML 4.01 Transitional//EN\">");

out.println("<HTML>");

out.println(" <HEAD><TITLE>A Servlet</TITLE></HEAD>");

out.println(" <BODY>");

out.println("<h2>"+"用户名："+this.getUsername()+"</h2>");

out.println("<h2>"+"密码："+this.getPassword()+"</h2>");

out.println(" </BODY>");

out.println("</HTML>");

out.flush();

out.close();

}

/**

* Initialization of the servlet. <br>

* @throws ServletException if an error occurs

public void init() throws ServletException {

// Put your code here

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

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

}

五测试

Servlet获取初始化参数

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