<%@ page cOntentType="text/html;charset=UTF-8" language="java" pageEncoding="UTF-8" %>



    




    

    

    猫

    狗

    鸡

    鸭


    

<%@ page import="java.util.Enumeration" %>
<%@ page cOntentType="text/html;charset=UTF-8" language="java" pageEncoding="UTF-8" %>



    
    



    
读取参数信息
    

            <%
                Enumeration parameterNames = request.getParameterNames();
                request.setCharacterEncoding("utf-8");
                while (parameterNames.hasMoreElements()){
                    String name = parameterNames.nextElement();
                    out.println("\n");
                    String url = request.getParameter(name);
                    out.println("\n");
                }
            %>

    

        

            
参数名
            
对应值
        
"+name+"
"+url+"
    <%

    %>

String   str   =   java.net.URLEncoder.encode("中文"，"UTF-8");            //编码
String   str   =   java.net.URLDecoder.decode("编码后的字符串","UTF-8");   // 解码

COOKIE COOKIE = new COOKIE("key","value");

[ ] ( ) = , " / ? @ : ;

COOKIE.setMaxAge(60*60*24);

response.addCOOKIE(COOKIE);

<%@ page cOntentType="text/html;charset=UTF-8" language="java" %>



    
    




    站点名: 
    

    网址: 
    

<%@ page import="java.net.URLEncoder" %>
<%@ page cOntentType="text/html;charset=UTF-8" language="java" pageEncoding="UTF-8" %>
<%
    // 编码，解决中文乱码
    String str = URLEncoder.encode(request.getParameter("name"),"utf-8");
    // 设置 name 和 url COOKIE
    COOKIE name = new COOKIE("name", str);
    COOKIE url = new COOKIE("url", request.getParameter("url"));

    // 设置COOKIE过期时间为24小时。
    name.setMaxAge(60*60*24);
    url.setMaxAge(60*60*24);

    // 在响应头部添加COOKIE
    response.addCOOKIE( name );
    response.addCOOKIE( url );
%>


    



设置 COOKIE


    
网站名:
        <%= request.getParameter("name")%>
    
    
网址:
        <%= request.getParameter("url")%>
    

<%@ page cOntentType="text/html;charset=UTF-8" language="java" %>
<%@ page import="java.net.*" %>



    
    


<%
    COOKIE COOKIE = null;
    COOKIE[] COOKIEs = null;
    // 获取COOKIEs的数据,是一个数组
    COOKIEs = request.getCOOKIEs();
    if( COOKIEs != null ){
        out.println("
 查找 COOKIE 名与值
");
        for (int i = 0; i ");
            out.print("参数值: " + URLDecoder.decode(COOKIE.getValue(), "utf-8") +" 
");
            out.print("------------------------------------
");
        }
    }else{
        out.println("
没有发现 COOKIE
");
    }
%>

<%@ page cOntentType="text/html;charset=UTF-8" language="java" %>
<%@ page import="java.net.*" %>



    
    


<%
    COOKIE COOKIE = null;
    COOKIE[] COOKIEs = null;
    // 获取当前域名下的COOKIEs，是一个数组
    COOKIEs = request.getCOOKIEs();
    if( COOKIEs != null ){
        out.println("
 查找 COOKIE 名与值
");
        for (int i = 0; i ");
            }
            out.print("参数名 : " + COOKIE.getName());
            out.print("
");
            out.print("参数值: " + URLDecoder.decode(COOKIE.getValue(), "utf-8") +" 
");
            out.print("------------------------------------
");
        }
    }else{
        out.println("
没有发现 COOKIE
");
    }
%>

void setAttribute(String name,Object val);

Object getAttribute(String name);

void removeAttribute(String name);

<%@ page cOntentType="text/html;charset=UTF-8" language="java" %>



    


<%
    //获取COOKIE的值
    String name = "";
    String pwd = "";
    COOKIE[] cs = request.getCOOKIEs();
    if(cs!=null){
        for(COOKIE c : cs){
            if("username".equals(c.getName())){
                name = c.getValue();
            }
            if("pwd".equals(c.getName())){
                pwd = c.getValue();
            }
        }
    }
%>
<%
    //获取request信息
    String message="";
    String mess = (String)request.getAttribute("message");
    if(mess!=null){
        message = mess;
    }
%>
用户登录
<%=message %>

    

        账号：
    
    

        密码：
    
    

        
    

package com.demo.servlet;

import javax.servlet.ServletException;
import javax.servlet.annotation.WebServlet;
import javax.servlet.http.*;
import java.io.IOException;
@WebServlet("/LoginServlet")
public class LoginServlet extends HttpServlet {

    @Override
    protected void doGet(HttpServletRequest req, HttpServletResponse resp) throws ServletException, IOException {
        doPost(req,resp);
    }

    public void doPost(HttpServletRequest request, HttpServletResponse response)
            throws ServletException, IOException {
        //设置请求的字符编码
        request.setCharacterEncoding("utf-8");
        //接收客户端请求
        String username = request.getParameter("username");
        String pwd = request.getParameter("pwd");
        //判断是否登录成功
        if("admin".equals(username) && "1234".equals(pwd)){
            //登录成功，把信息保存到COOKIE中
            COOKIE c1 = new COOKIE("username",username);
            COOKIE c2 = new COOKIE("pwd",pwd);
            c1.setMaxAge(60*60*24);
            c2.setMaxAge(60*60*24);
            response.addCOOKIE(c1);
            response.addCOOKIE(c2);
            //登录成功，保存用户名到session中，并重定向到LoginSuccess.jsp
            HttpSession session = request.getSession();
            session.setAttribute("username", username);
            response.sendRedirect("/LoginSuccess.jsp");
        }else{
            //转发给客户端“登录失败”
            request.setAttribute("message", "用户信息错误，请重新登录");
            request.getRequestDispatcher("/login.jsp").forward(request, response);
        }

    }
}

<%@ page cOntentType="text/html;charset=UTF-8" language="java" %>



    



<%
    //获取session信息
    String name = (String)session.getAttribute("username");
    if(name==null){
        //session不存在，转发到登录页面，并提示信息
        request.setAttribute("message", "您还没有登录，不能访问页面");
        request.getRequestDispatcher("/login.jsp").forward(request, response);
        //重定向到login.jsp，不会显示request提示的信息
        //response.sendRedirect("/login/login.jsp");
        return;
    }
%>
登录成功
你好<%=name %>，欢迎登录！