UseServlet.java

import java.io.IOException;

import javax.servlet.ServletException;
import javax.servlet.annotation.WebServlet;
import javax.servlet.http.*;


@WebServlet("/user.do")
public class UseServlet extends HttpServlet{

    private static final long serialVersionUID = 1L;
    @Override
    protected void doPost(HttpServletRequest req, HttpServletResponse resp)
            throws ServletException, IOException {
        //设置字符集格式为utf-8
        req.setCharacterEncoding("UTF-8");
        String name= req.getParameter("name");
        //将用户名进行格式编码
        name=java.net.URLEncoder.encode(name, "utf-8");
        //将用户名保存到cookie对象中
        Cookie nameCookie = new Cookie("userName", name);
        //设置cookie过期之前的时间，单位为s
        nameCookie.setMaxAge(60);
                nameCookie.setPath("/Servlet");
        //将cookie对象保存到客户端浏览器
        resp.addCookie(nameCookie);
        req.getRequestDispatcher("success.jsp").forward(req, resp);
        
    }
    @Override
    protected void doGet(HttpServletRequest req, HttpServletResponse resp)
            throws ServletException, IOException {
        doPost(req, resp);
    }
}

index.jsp

<form action="user.do" method="post">
    <%
        String userName=null;
        Cookie cookieArr[] = request.getCookies();
        if(cookieArr!=null&&cookieArr.length>0){
            for(Cookie c:cookieArr){
                if(c.getName().equals("userName")){
                    userName = URLDecoder.decode(c.getValue(), "utf-8");
                                        userName.toString();
                }
            }
        }
    %>
        <table align="center">
            <tr>
                <td>用户名：</td>
                <td><input type="text" name="name" value="<%if(userName!=null){out.println(userName);}%>"/></td>
            </tr>
            <tr>
                <td>密码：</td>
                <td><input type="password" name="pwd"/></td>
            </tr>
            <tr>
                <td colspan="2" align="center">
                <input type="submit" value="登录"/>
                <input type="reset" value="重置"/>
                </td>
            </tr>
        </table>
    </form>

success.jsp

    <b>登录成功！</b><br>
    您的信息为：<br/>
    <table align="center">
            <tr>
                <td>用户名：</td>
                <td><%=request.getParameter("name") %></td>
            </tr>
            <tr>
                <td>密码：</td>
                <td><%=request.getParameter("pwd") %></td>
            </tr>
            <tr>
            <td><a href="index.jsp">【回到主页】</a></td></tr>
    </table>

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