[网络协议]在init方法中通过ServletConfig对象获取注解中定义的两个初始化参数及其cookie记录显示登陆时间

一般的HTML表单，并按下面的要求定义一个Servlet，响应上面的登录表单请求。

该Servlet的类名自定义，并采用注解方式配置其访问的URL；
在注解中定义两个Servlet初始化参数，两个参数的参数名与参数值分别是：userName="admin" 和 pwd="123456"
在Servlet中重写init方法，在init方法中通过ServletConfig对象获取注解中定义的两个初始化参数；
在Servlet中处理响应表单提交的请求，获取用户在表单提交的用户名和密码，并和初始化的用户名和密码进行匹配，如果两者一样，就输出“登录成功”，并在5秒钟后跳转到home.jsp页面，反之则立即跳转到login.jsp页面。

import java.io.IOException;
import java.io.PrintWriter;
import java.sql.ResultSet;
import java.util.Date;

import javax.servlet.ServletConfig;
import javax.servlet.ServletException;
import javax.servlet.annotation.WebInitParam;
import javax.servlet.annotation.WebServlet;
import javax.servlet.http.Cookie;
import javax.servlet.http.HttpServlet;
import javax.servlet.http.HttpServletRequest;
import javax.servlet.http.HttpServletResponse;
import javax.servlet.http.HttpSession;
import javax.websocket.Session;
@WebServlet(
		urlPatterns = "/login.do",
		initParams = {
				@WebInitParam(name="userName",value = "admin"),
				@WebInitParam(name="pwd",value="123456")
		}
		)

public class servlet1 extends HttpServlet{
	private String str1;
	private String str2;
	
	public void init(ServletConfig config) {
			str1=config.getInitParameter("userName");
			str2=config.getInitParameter("pwd");
		}
	public void service(HttpServletRequest request,HttpServletResponse response)throws IOException,ServletException{
		response.setContentType("text/html;charset=utf-8");
		PrintWriter printWriter=response.getWriter();
		String name=request.getParameter("userName");
		String pwd=request.getParameter("password");
		if(name.equals(str1)&&pwd.equals(str2))
       {
	      printWriter.print("登录成功！");
	      printWriter.print("<meta http-equiv=\"refesh\" content=\"5;url=home.jsp\">");
       }
		else {
			response.sendRedirect("login.jsp");
		}
		
		
	}
}

cookie记录登录时间 每次刷新显示上次登录时间：

import java.io.IOException;
import java.io.PrintWriter;
import java.sql.ResultSet;
import java.text.SimpleDateFormat;
import java.util.Date;
import java.util.Iterator;

import javax.servlet.ServletConfig;
import javax.servlet.ServletException;
import javax.servlet.annotation.WebInitParam;
import javax.servlet.annotation.WebServlet;
import javax.servlet.http.Cookie;
import javax.servlet.http.HttpServlet;
import javax.servlet.http.HttpServletRequest;
import javax.servlet.http.HttpServletResponse;
import javax.servlet.http.HttpSession;
import javax.swing.plaf.basic.BasicInternalFrameTitlePane.MaximizeAction;
import javax.websocket.Session;




@WebServlet("/cookies")
public class servlet1 extends HttpServlet{
public void service(HttpServletRequest request,HttpServletResponse response)throws ServletException,IOException{
		response.setContentType("text/html;charset=UTF-8");
		SimpleDateFormat dateFormat=new SimpleDateFormat("hh:mm:ss");
		String string=dateFormat.format(new Date());
		PrintWriter ptPrintWriter=response.getWriter();
		
		Cookie [] cookies=new Cookie[100];
		Cookie[] cookies2=request.getCookies();
		if(cookies2==null)
		{
			ptPrintWriter.print("您是第一次访问本页面");
			cookies[0]=new Cookie("name"+0, string);
			response.addCookie(cookies[0]);
		}
		else {
			int i=0;
				cookies[i]=new Cookie("name"+i, string);
				response.addCookie(cookies[i]);
				i++;
				ptPrintWriter.print("您上一次访问本页面的时间是："+cookies2[i-1].getValue());
		}
		
	}
	
}

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