Servlet练习和自定义GenericServlet实现类

在web.xml文件中设置两个WEB应用的初始化参数，user、password

定义一个loginServlet，在其中获取请求的user，password，比对其和web.xml文件中定义的请求参数是否一致。若一致，响应Hello:xxx,若不一致，响应Sorry：xxx xxx为user。

Servlet:

  private ServletConfig servletConfig;
    @Override
    public void init(ServletConfig servletConfig) throws ServletException {
        System.out.println("init...");
        this.servletConfig = servletConfig;
    }

    @Override
    public void service(ServletRequest servletRequest, ServletResponse servletResponse) throws ServletException, IOException {
        System.out.println("service...");
//        1.获取请求参数：username,password
        String username = servletRequest.getParameter("username");
//        2.获取当前web应用的初始化参数：user，password
        String password = servletRequest.getParameter("password");
//        3.比对
        ServletContext servletContext = servletConfig.getServletContext();
        String initUser = servletContext.getInitParameter("user");
        String initPassword = servletContext.getInitParameter("password");

        PrintWriter printWriter = servletResponse.getWriter();
//        4.打印响应字符串
        if (username.equals(initUser) && password.equals(initPassword)){
            printWriter.print("Hello" + username);
        }else{
            printWriter.print("Sorry" + username);
        }
    }

　　

 web.xml:

    <!--配置当前web应用的初始化参数-->
    <context-param>
        <param-name>user</param-name>
        <param-value>YHS</param-value>
    </context-param>
    <context-param>
        <param-name>password</param-name>
        <param-value>123</param-value>
    </context-param>

    <servlet>
        <servlet-name>DengluServlet</servlet-name>
        <servlet-class>com.demo.javaweb.DengluServlet</servlet-class>
    </servlet>
    <servlet-mapping>
        <servlet-name>DengluServlet</servlet-name>
        <url-pattern>/DengluServlet</url-pattern>
    </servlet-mapping>

　　

package com.demo.javaweb;

import javax.servlet.*;
import java.io.IOException;
/*自定义的一个Servlet接口的实现类：让开发的任何Servlet都继承该类，以简化开发
* */
public class GenericServlet implements Servlet {
    private ServletConfig servletConfig;
    @Override
    public void init(ServletConfig servletConfig) throws ServletException {
        this.servletConfig = servletConfig;
    }

    @Override
    public ServletConfig getServletConfig() {
        return servletConfig;
    }

    @Override
    public void service(ServletRequest servletRequest, ServletResponse servletResponse) throws ServletException, IOException {

    }

    @Override
    public String getServletInfo() {
        return null;
    }

    @Override
    public void destroy() {

    }
}