Servlet获取配置信息里的初始化参数

Servlet当中的代码：

package com.test;

import java.io.IOException;

import javax.servlet.ServletConfig;
import javax.servlet.ServletException;
import javax.servlet.http.HttpServlet;
import javax.servlet.http.HttpServletRequest;
import javax.servlet.http.HttpServletResponse;

public class DispatcherServlet extends HttpServlet {
    private static final long serialVersionUID = 1L;
    //定义参数
    String prefix = "";
    String suffix = "";
    public DispatcherServlet() {
        super();
    }
    @Override
    public void init(ServletConfig config) throws ServletException {
        //获取配置信息里的初始化参数，并赋值
        prefix = config.getInitParameter("prefix");
        suffix = config.getInitParameter("suffix");
        System.out.println(config.getInitParameter("prefix"));
        System.out.println(config.getInitParameter("suffix"));
    }
    
    protected void doGet(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException {
        //获取上一个页面传来的名为action的参数
        String action = request.getParameter("action");
        //跳转到指定页面
        request.getRequestDispatcher(prefix+action+suffix).forward(request, response);
    }

    protected void doPost(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException {
        doGet(request, response);
    }

}

web.xml中的配置：

<?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" xsi:schemaLocation="http://java.sun.com/xml/ns/javaee http://java.sun.com/xml/ns/javaee/web-app_3_0.xsd" id="WebApp_ID" version="3.0">

  <servlet>
     <servlet-name>DispatcherServlet</servlet-name>
    <servlet-class>com.test.DispatcherServlet</servlet-class>
    <init-param>
        <param-name>prefix</param-name>
        <param-value>WEB-INF/jsp/</param-value>
    </init-param>
    <init-param>
        <param-name>suffix</param-name>
        <param-value>.jsp</param-value>
    </init-param>
    
  </servlet>
  <servlet-mapping>
    <servlet-name>DispatcherServlet</servlet-name>
    <url-pattern>/DispatcherServlet</url-pattern>
  </servlet-mapping>
  
</web-app>