会话管理技术实战(用户登录案例)

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别团等shy哥发育 2023-02-13 14:43:48 博主文章分类：web ©著作权

文章标签 session servlet cookie java 用户名 文章分类 Java 后端开发

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会话管理技术实战(用户登录案例)_servlet

[1].创建一个User类，封装用户名和密码。
[2].提供一个首页面，欢迎用户登录:IndexServlet，提供一个退出的链接。
[3].提供一个登录的Servlet:处理登录请求。
[4].提供一个退出的Servlet:处理退出首页面的功能。

登录界面:login.html

<!DOCTYPE html>
<html>
<head>
<meta charset="UTF-8">
<title>Insert title here</title>
</head>
<body>
      <form action="/chapter05/LoginServlet" method="post">
  用户名：<input type="text" name="username"><br/>
  密码:  <input type="password" name="password"/><br/>
  <input type="submit" value="提交" id="bt"/>
   </form>
</body>
</html>

User.java:

package cn.itcast.chapter05.example02;
/*
 * alt+shift+a:一次性写多行代码
 */
public class User {
      private String name;
      private String password;
  public User() { 
  }
  public String getName() {
    return name;
  }
  public void setName(String name) {
    this.name = name;
  }
  public String getPassword() {
    return password;
  }
  public void setPassword(String password) {
    this.password = password;
  }
}

LoginServlet.java(login.html表单的数据提交到了这里)

package cn.itcast.chapter05.example02;

import java.io.IOException;

import javax.servlet.ServletException;
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;

/**
 * Servlet implementation class LoginServlet
 */
public class LoginServlet extends HttpServlet {
    private static final long serialVersionUID = 1L;
       
    protected void doGet(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException {
        response.setContentType("text/html;charset=utf-8");
        request.setCharacterEncoding("utf-8");
        //1.获取用户名和密码
        String name=request.getParameter("username");
        String psw=request.getParameter("password");
    //    System.out.println("username="+name+"password="+psw);
        //2.判断用户名和密码是否正确 用户名是传智播客  密码是123，就认为是正确的
        if("传智播客".equals(name)&&"123".equals(psw)) {
           //这里本应查数据库，代码量会更大，暂时模拟一下
            //登陆成功，跳转到主页面,保存用户信息
            User u=new User();
            u.setName(name);
            u.setPassword(psw);
            HttpSession session=request.getSession();
            session.setAttribute("key",u);
            //自己创建cookie，让session使用自己的cookie,不用默认cookie
            Cookie c=new Cookie("JESSIONID",session.getId());
            c.setMaxAge(3600*24*7);
            c.setPath("/chapter05");
            response.sendRedirect("/chapter05/index");
        }else {
            //登录失败
            response.getWriter().print("用户名和密码错误，登陆失败！");
        }
        
        
        
    }

    /**
     * @see HttpServlet#doPost(HttpServletRequest request, HttpServletResponse response)
     */
    protected void doPost(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException {
        // TODO Auto-generated method stub
        doGet(request, response);
    }

}

IndexServlet.java(登陆成功之后的显示界面)

package cn.itcast.chapter05.example02;

import java.io.IOException;
import javax.servlet.ServletException;
import javax.servlet.http.HttpServlet;
import javax.servlet.http.HttpServletRequest;
import javax.servlet.http.HttpServletResponse;
import javax.servlet.http.HttpSession;

/**
 * Servlet implementation class IndexServlet
 */
public class IndexServlet extends HttpServlet {
  private static final long serialVersionUID = 1L;

  protected void doGet(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException {
    //用来欢迎用户登录，并且显示用户信息
    response.setContentType("text/html;charset=utf-8");
    //1.获取用户信息
    HttpSession session=request.getSession();
    User user=(User)session.getAttribute("key");
    //2.判断用户是否存在
    if(user==null) {//用户不存在,也就是用户根本没有登录
      response.sendRedirect("/chapter05/login.html");
    }else {
      String name=user.getName();
      String url="<a href='/chapter05/logOut'>退出</a>";
      response.getWriter().print("欢迎您: "+name+" 登录本网站  "+url);
    }
  }

  /**
   * @see HttpServlet#doPost(HttpServletRequest request, HttpServletResponse response)
   */
  protected void doPost(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException {
    // TODO Auto-generated method stub
    doGet(request, response);
  }
}

退出界面:LogOutServlet.java(销毁session)

package cn.itcast.chapter05.example02;

import java.io.IOException;
import javax.servlet.ServletException;
import javax.servlet.http.HttpServlet;
import javax.servlet.http.HttpServletRequest;
import javax.servlet.http.HttpServletResponse;
import javax.servlet.http.HttpSession;

/**
 * 退出功能
 */
public class LogOutServlet extends HttpServlet {
  private static final long serialVersionUID = 1L;
       
  protected void doGet(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException {
      //清空session
    HttpSession session=request.getSession();
    session.removeAttribute("key");
    session.invalidate(); 
  }

  /**
   * @see HttpServlet#doPost(HttpServletRequest request, HttpServletResponse response)
   */
  protected void doPost(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException {
    // TODO Auto-generated method stub
    doGet(request, response);
  }

}