Java Web学习(32)： Servlet学习(五)

时间：2016-08-05 16:13:41 阅读：230 评论：0 收藏：0 [点我收藏+]

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获取初始化参数

在web.xml中配置Servlet时或者在注解中配置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。

例子：

ServletDemo：

package com.servlet;


import java.io.IOException;
import java.io.PrintWriter;


import javax.servlet.ServletConfig;
import javax.servlet.ServletException;
import javax.servlet.annotation.WebInitParam;
import javax.servlet.annotation.WebServlet;
import javax.servlet.http.HttpServlet;
import javax.servlet.http.HttpServletRequest;
import javax.servlet.http.HttpServletResponse;


/**
 * Servlet implementation class ServletDemmo
 */
@WebServlet(name="ServletDemo" ,urlPatterns={"/ServletDemo"},
              initParams={  
                          @WebInitParam(name="username",value="admin"),  
                          @WebInitParam(name="password",value="123456")  
             })  
public class ServletDemo extends HttpServlet {
	private static final long serialVersionUID = 1L;
       
	private String username;
	private String password;
	
	
	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;
	}


    /**
     * @see HttpServlet#HttpServlet()
     */
    public ServletDemo() {
        super();
        // TODO Auto-generated constructor stub
    }


	/**
	 * @see Servlet#init(ServletConfig)
	 */
	public void init(ServletConfig config) throws ServletException {
		this.username = config.getInitParameter("username");
		this.password = config.getInitParameter("password");
	}


	/**
	 * @see Servlet#destroy()
	 */
	public void destroy() {
		// TODO Auto-generated method stub
	}


	/**
	 * @see HttpServlet#doGet(HttpServletRequest request, HttpServletResponse response)
	 */
	protected void doGet(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException {
		// TODO Auto-generated method stub
		response.setContentType("text/html;charset=UTF-8");
		PrintWriter out = response.getWriter();
		out.print("<h1>用户名："+this.getUsername()+"</h1>");
		out.print("<h1>密码："+this.getPassword()+"</h1>");
	}


	/**
	 * @see HttpServlet#doPost(HttpServletRequest request, HttpServletResponse response)
	 */
	protected void doPost(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException {
		// TODO Auto-generated method stub
		doGet(request, response);
	}


}

index.jsp页面源码：

<%@ page language="java" contentType="text/html; charset=UTF-8"
    pageEncoding="UTF-8"%>
<!DOCTYPE html PUBLIC "-//W3C//DTD HTML 4.01 Transitional//EN" "http://www.w3.org/TR/html4/loose.dtd">
<html>
<head>
<meta http-equiv="Content-Type" content="text/html; charset=UTF-8">
<title>Servlet编程</title>
</head>
<body>
       <h1>获取初始化参数</h1>
       <hr/>
       <a href="ServletDemo">获取初始化参数ServletDemo</a>
</body>
</html>

运行结果：

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