Session保存用户名到Session域对象中

Session保存用户名

1.构造登录界面

<!DOCTYPE html>
<html>
<head>
<meta charset="UTF-8">
<title>Session保存用户名</title>
</head>
<body>
 
<form action="doS3" method= "post">
    用户名:<input type="text" name="name"/><br/>
    密   码:<input type="password" name = "pwd"><br/>
    <input type="submit">
</form>
 
</body>
</html>

　　2.获取Session并将用户名保存到Session域对象中

package com.oaec.session;
 
import java.io.IOException;
import java.util.Date;
 
import javax.servlet.ServletException;
import javax.servlet.http.HttpServlet;
import javax.servlet.http.HttpServletRequest;
import javax.servlet.http.HttpServletResponse;
import javax.servlet.http.HttpSession;
 
public class servletDemo3 extends HttpServlet {
    @Override
    protected void doGet(HttpServletRequest req, HttpServletResponse resp) throws ServletException, IOException {
        req.setCharacterEncoding("UTF-8");
        resp.setContentType("text/html;charset=UTF-8");
        // req.getAttribute(arg0)
        String name = req.getParameter("name");
        String pwd = req.getParameter("pwd");
        if ("高圆圆".equals(name) && "123".equals(pwd)) {
            // 将用户名保存在session中
            // 1.获得session
            HttpSession session = req.getSession();
            // 2.将用户名保存在session中
            session.setAttribute("uname", name);
            resp.sendRedirect("doS4");
 
        } else {
            resp.sendRedirect("index.html");
        }
    }
 
    @Override
    protected void doPost(HttpServletRequest req, HttpServletResponse resp) throws ServletException, IOException {
        doGet(req, resp);
    }
}

3.从Session中取出数据并对页面进行保护没有登录通过URL访问直接重定向到登录界面即主页

package com.oaec.session;
 
import java.io.IOException;
import java.io.PrintWriter;
import java.util.Date;
 
import javax.servlet.ServletException;
import javax.servlet.http.HttpServlet;
import javax.servlet.http.HttpServletRequest;
import javax.servlet.http.HttpServletResponse;
import javax.servlet.http.HttpSession;
 
public class servletDemo4 extends HttpServlet{
    @Override
    protected void doGet(HttpServletRequest req, HttpServletResponse resp) throws ServletException, IOException {
        req.setCharacterEncoding("UTF-8");
        resp.setContentType("text/html;charset=UTF-8");
        //从session中取出数据
        HttpSession session = req.getSession(false);
        Object object = null;
        if (session != null && (object = session.getAttribute("uname"))!=null) {        
                PrintWriter writer = resp.getWriter();
                writer.write("登录成功<br>");
                writer.write("欢迎你"+object);
            }else {
                //没有登录过 直接重定向到主页
                resp.sendRedirect("index.html");
            }
        }
    @Override
    protected void doPost(HttpServletRequest req, HttpServletResponse resp) throws ServletException, IOException {
        doGet(req, resp);
    }
}