【JavaEE】javaee基础Session与Cookie的基本使用——聊天室案例

别倒在黎明之前

已于 2023-08-26 23:26:32 修改

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文章标签： tomcat java-ee

于 2023-07-26 22:50:31 首次发布

本文链接：https://blog.youkuaiyun.com/c1390527393/article/details/131949303

版权

该案例通过servlet对于Session与Cookie的一些用法所完成

java类

@WebServlet("/loveCaht")
public class chat extends HttpServlet {
    @Override
    protected void doPost(HttpServletRequest req, HttpServletResponse resp) throws ServletException, IOException {
        //处理请求报文的中文乱码
        req.setCharacterEncoding("utf-8");
        //获取聊天发言
        String ip = req.getRemoteAddr();
        //获取ip地址
        String chat = req.getParameter("chat");

        //根据发言次数，确定聊天表情
        HttpSession session = req.getSession();
        Integer chatCount = (Integer) session.getAttribute("chat_count");
        if (chatCount==null){
            chatCount=1;
            session.setAttribute("chat_count",chatCount);
        }

        //根据不同的发言次数，使用不同的表情图片
        String face ="";
        if(chatCount>=5){
            face="<img src='pic/face1.png'/>";
        }else if (chatCount>=3){
            face="<img src='pic/face2.png'/>";
        }else {
            face="<img src='pic/face3.png'/>";
        }

        session.setAttribute("chat_count",chatCount+1);
        String chatMsg = String.format("%s%s说:%s[%s]", ip,face,chat, LocalTime.now());

        //application应用程序范围存储
        ServletContext application = req.getServletContext();

        //获取application范围内存存储的聊天记录
        List<String> messageList = (List<String>) application.getAttribute("chat_message_list");
        if (messageList==null){
            messageList =new ArrayList<String>();
            application.setAttribute("chat_message_list",messageList);
        }

        //添加聊天记录
        messageList.add(chatMsg);

        //使用cookie统计发言次数
        //获取Cookie
        Cookie[] cookies = req.getCookies();

        int total =1;
        if (cookies!=null){
            //查找知道Cookie
            Cookie cookieTotal =null;
            for (Cookie cookie : cookies) {
                if (cookie.getName().equals("total")){
                    cookieTotal =cookie;
                    total=Integer.parseInt(cookie.getValue());
                    break;
                }
            }
            if (cookieTotal==null){
                cookieTotal = new Cookie("total",String.valueOf(total));
            }else {
                cookieTotal = new Cookie("total",String.valueOf(total+1)) ;
            }
            cookieTotal.setMaxAge(-1);
            resp.addCookie(cookieTotal);
        }

        //显示聊天记录
        resp.setContentType("text/html;charset=utf-8");
        PrintWriter writer = resp.getWriter();
        writer.write("<h3>总发言次数"+total+"<h3/>");

        for (String s : messageList) {
            writer.write("<h5>"+s+"<h5/>");
        }

        //返回发送消息界面按钮
        writer.write("<form action=chat.html ><button>返回</button></form>");
        writer.flush();

    }
}

chat.html

<!DOCTYPE html>
<html>
<head>
<meta charset="UTF-8">
<title>激情聊天室</title>
</head>
<body>
	<form action="loveCaht" method="post">
		<input name="chat"/>
		<button>发言</button>
	</form>
</body>
</html>

运行展示