JavaWeb---通过ServletConfig获取Servlet的初始化参数

package com.zyz;

import javax.servlet.ServletConfig;

import javax.servlet.ServletException;

import javax.servlet.http.HttpServlet;

import javax.servlet.http.HttpServletRequest;

import javax.servlet.http.HttpServletResponse;

import java.io.IOException;

import java.util.Enumeration;

/**

 * Created by Administrator on 16-9-29.

 */

public class ConfigServlet extends HttpServlet {

    private ServletConfig config;//此成员变量用来接收ServletConfig对象

    /**

     * 当Servlet配置了初始化参数后，web容器在创建Servlet实例对象时，

     * 会自动将这些初始化参数封装在ServletConfig对象中，并在调用Servlet的

     * init方法时，将ServletConfig对象传给Servlet。进而，程序通过ServletConfig

     * 就可以得到初始化参数信息

     * @param config

     */

    @Override

    public void init(ServletConfig config){

        this.config=config;

    }

    @Override

    protected void doGet(HttpServletRequest req, HttpServletResponse resp) throws ServletException, IOException {

        resp.setHeader("Content-Type","text/html;charset=utf8");

        resp.getWriter().write("从web.xml中获取初始化参数<hr>");

        Enumeration<String> paraNames=config.getInitParameterNames();

        /**

         * getInitParameterNames得到的是是枚举类型Enumeration

         *

         */

        while (paraNames.hasMoreElements()){

            String paraName=paraNames.nextElement();

            String paraValue=config.getInitParameter(paraName);

            resp.getWriter().print(paraName+":"+paraValue+"<br>");

        }

    }

}