• java-自动登录 与 记住用户名

    步骤分析：

    步骤分析:
	1.数据库和表
		create database day16;
		use day16;
		create table user(
			id int primary key auto_increment,
			username varchar(20),
			password varchar(20)
		);
		insert into user values(null,'tom','123');
	2.web项目
		jar包 工具类 配置文件
	3.新建一个登录页面 表单
	4.表单提交 loginservlet
		接受用户名和密码
		调用service完成登录操作,返回值User
		判断user是否为空
			若不为空,将user放入session中
				判断是否勾选了自动登录
					若勾选了:
						需要将用户名和密码写回浏览器
	5.下次访问网站的时候
		过滤器拦截任意请求
			判断有无指定的cookie
				有cookie,获取用户名和密码
				调用service完成登录操作,返回user
				当user不为空的时候将user放入session中.

当我们换用jack登录的时候发现登录不了
	自动登录只需要登录一次:当session中没有用户的时候
	访问有些资源是不需要自动登录的(和登录还有注册相关的资源)
	
	修改filter的逻辑:
		首先判断session中是否有user
			若没有 并且访问的路径不是和登录注册相关的时候
				才去获取指定的cookie

    项目结构：


    项目展示：

    数据库：

    /*
SQLyog Ultimate v12.09 (64 bit)
MySQL - 5.5.53 : Database - autologin
*********************************************************************
*/


/*!40101 SET NAMES utf8 */;

/*!40101 SET SQL_MODE=''*/;

/*!40014 SET @OLD_UNIQUE_CHECKS=@@UNIQUE_CHECKS, UNIQUE_CHECKS=0 */;
/*!40014 SET @OLD_FOREIGN_KEY_CHECKS=@@FOREIGN_KEY_CHECKS, FOREIGN_KEY_CHECKS=0 */;
/*!40101 SET @OLD_SQL_MODE=@@SQL_MODE, SQL_MODE='NO_AUTO_VALUE_ON_ZERO' */;
/*!40111 SET @OLD_SQL_NOTES=@@SQL_NOTES, SQL_NOTES=0 */;
CREATE DATABASE /*!32312 IF NOT EXISTS*/`autologin` /*!40100 DEFAULT CHARACTER SET utf8 */;

USE `autologin`;

/*Table structure for table `user` */

DROP TABLE IF EXISTS `user`;

CREATE TABLE `user` (
  `id` int(11) NOT NULL AUTO_INCREMENT COMMENT '主键',
  `username` varchar(255) DEFAULT NULL COMMENT '用户名',
  `password` varchar(255) DEFAULT NULL COMMENT '密码',
  PRIMARY KEY (`id`)
) ENGINE=InnoDB AUTO_INCREMENT=3 DEFAULT CHARSET=utf8;

/*Data for the table `user` */

insert  into `user`(`id`,`username`,`password`) values (1,'tom','123'),(2,'jack','123');

/*!40101 SET SQL_MODE=@OLD_SQL_MODE */;
/*!40014 SET FOREIGN_KEY_CHECKS=@OLD_FOREIGN_KEY_CHECKS */;
/*!40014 SET UNIQUE_CHECKS=@OLD_UNIQUE_CHECKS */;
/*!40111 SET SQL_NOTES=@OLD_SQL_NOTES */;

    项目代码：

    com.gordon.constant:

    --

    package com.gordon.constant;

public class Constant {
	/**
	 * 是否自动登录
	 */
	public static String IS_AUTO_LOGIN = "ok";
	
	/**
	 * 是否记住用户名
	 */
	public static String IS_REMEMBER_USER = "ok";
}

    com.gordon.dao:

    --UserDao.java:

    package com.gordon.dao;

import java.sql.SQLException;

import org.apache.commons.dbutils.QueryRunner;
import org.apache.commons.dbutils.handlers.BeanHandler;

import com.gordon.domain.User;
import com.gordon.utils.DataSourceUtil;

public class UserDao {

	/**
	 * 用户登录
	 * 
	 * @param username
	 * @param password
	 * @return
	 * @throws SQLException 
	 */
	public User login(String username, String password) throws SQLException {
		QueryRunner qr = new QueryRunner(DataSourceUtil.getDataSource());
		String sql = "select * from user where username = ? and password = ? limit 1";
		return qr.query(sql, new BeanHandler<User>(User.class), username, password);
	}

}

    com.gordon.domain:

    --User.java:

    package com.gordon.domain;

public class User {
	private int id;
	private String username;
	private String password;

	public User() {
	}

	public User(int id, String username, String password) {
		this.id = id;
		this.username = username;
		this.password = password;
	}

	public int getId() {
		return id;
	}

	public void setId(int id) {
		this.id = id;
	}

	public String getUsername() {
		return username;
	}

	public void setUsername(String username) {
		this.username = username;
	}

	public String getPassword() {
		return password;
	}

	public void setPassword(String password) {
		this.password = password;
	}
}

    com.gordon.service:

    --UserService.java:

    package com.gordon.service;

import java.sql.SQLException;

import com.gordon.dao.UserDao;
import com.gordon.domain.User;

public class UserService {

	/**
	 * 用户登录
	 * @param username
	 * @param password
	 * @return
	 * @throws SQLException 
	 */
	public User login(String username, String password) throws SQLException {
		return new UserDao().login(username, password);
	}

}

    com.gordon.utils:

    --CookieUtil.java

    package com.gordon.utils;

import javax.servlet.http.Cookie;
import javax.servlet.http.HttpServletRequest;
import javax.servlet.http.HttpServletResponse;

/**
 * Cookie工具类
 * 
 */
public class CookieUtil {

	/**
	 * 添加cookie
	 * 
	 * @param response
	 * @param name
	 * @param value
	 * @param maxAge
	 */
	public static void addCookie(HttpServletResponse response, String name, String value) {
		Cookie cookie = new Cookie(name, value);
		cookie.setPath("/");
		response.addCookie(cookie);
	}

	/**
	 * 添加cookie
	 * 
	 * @param response
	 * @param name
	 * @param value
	 * @param maxAge
	 */
	public static void addCookie(HttpServletResponse response, String name, String value, int maxAge) {
		Cookie cookie = new Cookie(name, value);
		cookie.setPath("/");
		if (maxAge > 0) {
			cookie.setMaxAge(maxAge);
		}
		response.addCookie(cookie);
	}

	/**
	 * 删除cookie
	 * 
	 * @param response
	 * @param name
	 */
	public static void removeCookie(HttpServletResponse response, String name) {
		Cookie uid = new Cookie(name, null);
		uid.setPath("/");
		uid.setMaxAge(0);
		response.addCookie(uid);
	}

	/**
	 * 获取cookie值
	 * 
	 * @param request
	 * @return
	 */
	public static String getUid(HttpServletRequest request, String cookieName) {
		Cookie cookies[] = request.getCookies();
		for (Cookie cookie : cookies) {
			if (cookie.getName().equals(cookieName)) {
				return cookie.getValue();
			}
		}
		return null;
	}
}

    --DataSourceUtil.java:

    package com.gordon.utils;

import java.sql.Connection;
import java.sql.ResultSet;
import java.sql.SQLException;
import java.sql.Statement;

import javax.sql.DataSource;

import com.mchange.v2.c3p0.ComboPooledDataSource;

public class DataSourceUtil {
	private static ComboPooledDataSource ds = new ComboPooledDataSource();

	/**
	 * 获取数据源
	 * 
	 * @return 连接池
	 */
	public static DataSource getDataSource() {
		return ds;
	}

	/**
	 * 获取连接
	 * 
	 * @return 连接
	 * @throws SQLException
	 */
	public static Connection getConnection() throws SQLException {
		return ds.getConnection();
	}

	/**
	 * 释放资源
	 * 
	 * @param conn
	 *            连接
	 * @param st
	 *            语句执行者
	 * @param rs
	 *            结果集
	 */
	public static void closeResource(Connection conn, Statement st, ResultSet rs) {
		closeResultSet(rs);
		closeStatement(st);
		closeConn(conn);
	}

	/**
	 * 释放连接
	 * 
	 * @param conn
	 *            连接
	 */
	public static void closeConn(Connection conn) {
		if (conn != null) {
			try {
				conn.close();
			} catch (SQLException e) {
				e.printStackTrace();
			}
			conn = null;
		}

	}

	/**
	 * 释放语句执行者
	 * 
	 * @param st
	 *            语句执行者
	 */
	public static void closeStatement(Statement st) {
		if (st != null) {
			try {
				st.close();
			} catch (SQLException e) {
				e.printStackTrace();
			}
			st = null;
		}

	}

	/**
	 * 释放结果集
	 * 
	 * @param rs
	 *            结果集
	 */
	public static void closeResultSet(ResultSet rs) {
		if (rs != null) {
			try {
				rs.close();
			} catch (SQLException e) {
				e.printStackTrace();
			}
			rs = null;
		}

	}
}

    com.gordon.web.filter:

    --AutoLoginFilter.java

    package com.gordon.web.filter;

import java.io.IOException;
import java.net.URLDecoder;

import javax.servlet.Filter;
import javax.servlet.FilterChain;
import javax.servlet.FilterConfig;
import javax.servlet.ServletException;
import javax.servlet.ServletRequest;
import javax.servlet.ServletResponse;
import javax.servlet.annotation.WebFilter;
import javax.servlet.http.HttpServletRequest;
import javax.servlet.http.HttpServletResponse;

import com.gordon.domain.User;
import com.gordon.service.UserService;
import com.gordon.utils.CookieUtil;

/**
 * 自动登录过滤器
 */
@WebFilter(urlPatterns = { "/*" })
public class AutoLoginFilter implements Filter {

	public AutoLoginFilter() {
	}

	public void destroy() {
	}

	public void doFilter(ServletRequest request, ServletResponse response, FilterChain chain)
			throws IOException, ServletException {

		HttpServletRequest req = (HttpServletRequest) request;
		HttpServletResponse resp = (HttpServletResponse) response;

		// 判断用户是否已经登录,如果不存在user，则未登录，开始自动登录
		if (req.getSession().getAttribute("user") == null) {

			// 判断是否存在cookie
			if (CookieUtil.getUid(req, "autologin") != null) {

				// 排除指定的路径（指定路径下不需要自动登录，如登录请求，注册请求）
				if (!req.getServletPath().contains("/login")) {

					System.out.println("执行了自动登录操作......");

					// 获取cookie中的用户名密码
					String userCookieValue = CookieUtil.getUid(req, "autologin");
					String username = userCookieValue.split("-")[0];
					String password = userCookieValue.split("-")[1];

					User user = null;
					try {
						user = new UserService().login(URLDecoder.decode(username, "UTF-8"), password);
					} catch (Exception e) {
						e.printStackTrace();
					}

					if (user != null) {
						// 将user放入session
						req.getSession().setAttribute("user", user);

						// 直接转入成功页面，不需要自动传递
						resp.sendRedirect(req.getContextPath() + "/");
					}
				}
			}
		}

		chain.doFilter(request, response);
	}

	public void init(FilterConfig fConfig) throws ServletException {
	}
}

    com.gordon.web.servlet:

    --LoginServlet.java

    package com.gordon.web.servlet;

import java.io.IOException;
import java.net.URLEncoder;
import java.sql.SQLException;

import javax.servlet.ServletException;
import javax.servlet.annotation.WebServlet;
import javax.servlet.http.HttpServlet;
import javax.servlet.http.HttpServletRequest;
import javax.servlet.http.HttpServletResponse;

import com.gordon.constant.Constant;
import com.gordon.domain.User;
import com.gordon.service.UserService;
import com.gordon.utils.CookieUtil;

/**
 * 用户登录
 */
@WebServlet("/login")
public class LoginServlet extends HttpServlet {

	private static final long serialVersionUID = 1L;

	protected void doGet(HttpServletRequest request, HttpServletResponse response)
			throws ServletException, IOException {

		request.setCharacterEncoding("utf-8");

		String username = request.getParameter("username");
		String password = request.getParameter("password");
		String autologin = request.getParameter("autologin");
		String rememberuser = request.getParameter("rememberuser");

		User user = null;
		try {
			user = new UserService().login(username, password);
		} catch (SQLException e) {
			e.printStackTrace();
		}

		if (user != null) {

			// 将user放入session
			request.getSession().setAttribute("user", user);

			// 如果开启记住用户名，将用户名称存入cookie
			if (rememberuser != null && Constant.IS_REMEMBER_USER.equals(rememberuser)) {

				// 记住用户名cookie存储60天
				CookieUtil.addCookie(response, "rememberuser", URLEncoder.encode(user.getUsername(), "UTF-8"),
						60 * 24 * 3600);
			}

			// 如果开启自动登录，将用户存入cookie
			if (autologin != null && Constant.IS_AUTO_LOGIN.equals(autologin)) {

				// 自动登录Cookie存储30天
				CookieUtil.addCookie(response, "autologin",
						URLEncoder.encode(user.getUsername(), "UTF-8") + "-" + user.getPassword(), 30 * 24 * 3600);
			}
		}

		response.sendRedirect(request.getContextPath() + "/");
	}

	protected void doPost(HttpServletRequest request, HttpServletResponse response)
			throws ServletException, IOException {
		doGet(request, response);
	}

}

    --LogoutServlet.java

    package com.gordon.web.servlet;

import java.io.IOException;

import javax.servlet.ServletException;
import javax.servlet.annotation.WebServlet;
import javax.servlet.http.HttpServlet;
import javax.servlet.http.HttpServletRequest;
import javax.servlet.http.HttpServletResponse;

import com.gordon.utils.CookieUtil;

/**
 * 用户登录
 */
@WebServlet("/logout")
public class LogoutServlet extends HttpServlet {

	private static final long serialVersionUID = 1L;

	protected void doGet(HttpServletRequest request, HttpServletResponse response)
			throws ServletException, IOException {

		request.getSession().removeAttribute("user");
		CookieUtil.removeCookie(response, "autologin");

		response.sendRedirect(request.getContextPath() + "/");
	}

	protected void doPost(HttpServletRequest request, HttpServletResponse response)
			throws ServletException, IOException {
		doGet(request, response);
	}

}

    c3p0-config.xml:

    <c3p0-config>
	<!-- 默认配置，如果没有指定则使用这个配置 -->
	<default-config>
		<!-- 基本配置 -->
		<property name="driverClass">com.mysql.jdbc.Driver</property>
		<property name="jdbcUrl">jdbc:mysql://localhost:3306/autologin</property>
		<property name="user">root</property>
		<property name="password">root</property>
	
		<!--扩展配置-->
		<property name="checkoutTimeout">30000</property>
		<property name="idleConnectionTestPeriod">30</property>
		<property name="initialPoolSize">10</property>
		<property name="maxIdleTime">30</property>
		<property name="maxPoolSize">100</property>
		<property name="minPoolSize">10</property>
		<property name="maxStatements">200</property>
	</default-config> 
	
	
	<!-- 命名的配置 -->
	<named-config name="itcast">
		<property name="driverClass">com.mysql.jdbc.Driver</property>
		<property name="jdbcUrl">jdbc:mysql://127.0.0.1:3306/xxxx</property>
		<property name="user">root</property>
		<property name="password">1234</property>
		
		
		<!-- 如果池中数据连接不够时一次增长多少个 -->
		<property name="acquireIncrement">5</property>
		<property name="initialPoolSize">20</property>
		<property name="minPoolSize">10</property>
		<property name="maxPoolSize">40</property>
		<property name="maxStatements">20</property>
		<property name="maxStatementsPerConnection">5</property>
	</named-config>
</c3p0-config>

    -----------------------------------------------------

    index.jsp

    <%@ page language="java" contentType="text/html; charset=UTF-8" pageEncoding="UTF-8"%>
<%@taglib prefix="c" uri="http://java.sun.com/jsp/jstl/core"%>
<!DOCTYPE html PUBLIC "-//W3C//DTD HTML 4.01 Transitional//EN" "http://www.w3.org/TR/html4/loose.dtd">
<html>
<head>
<meta http-equiv="Content-Type" content="text/html; charset=UTF-8">
<title>Insert title here</title>
</head>
<body>
	<c:set var="username" value="${ sessionScope.user.username }"></c:set>
	<c:choose>
		<c:when test="${ not empty username }">
			网站首页：欢迎您的使用：${ username } | <a href="${ pageContext.request.contextPath }/logout">退出登录</a>
		</c:when>
		<c:otherwise>
			您还没有登录，请登录：<a href="${ pageContext.request.contextPath }/login.jsp">登录</a>
		</c:otherwise>
	</c:choose>
</body>
</html>

    login.jsp

    <%@ page language="java" contentType="text/html; charset=UTF-8" pageEncoding="UTF-8"%>
<!DOCTYPE html PUBLIC "-//W3C//DTD HTML 4.01 Transitional//EN" "http://www.w3.org/TR/html4/loose.dtd">
<html>
<head>
<meta http-equiv="Content-Type" content="text/html; charset=UTF-8">
<title>Insert title here</title>
</head>
<body>
	<form action="${ pageContext.request.contextPath }/login" method="post">
		<table>
			<tr>
				<td>用户名：</td>
				<td><input type="text" name="username" value="${ cookie.rememberuser.value }" /></td>
			</tr>
			<tr>
				<td>密码：</td>
				<td><input type="text" name="password" /></td>
			</tr>
			<tr>
				<td><input type="checkbox" name="rememberuser" value="ok" />记住用户名</td>
				<td><input type="checkbox" name="autologin" value="ok" />自动登录</td>
			</tr>
			<tr>
				<td colspan="2"><input type="submit" value="登录" /></td>
			</tr>
		</table>
	</form>
</body>
</html>

    show_product.jsp

    <%@ page language="java" contentType="text/html; charset=UTF-8" pageEncoding="UTF-8"%>
<!DOCTYPE html PUBLIC "-//W3C//DTD HTML 4.01 Transitional//EN" "http://www.w3.org/TR/html4/loose.dtd">
<html>
<head>
<meta http-equiv="Content-Type" content="text/html; charset=UTF-8">
<title>Insert title here</title>
</head>
<body>
	商品展示：欢迎您的使用：${ sessionScope.user.username } |
	<a href="${ pageContext.request.contextPath }/logout">退出登录</a>
</body>
</html>
  • 相关阅读:
    java NIO 总结
    NIO 服务器和客户端 demo
    nio channel demo
    使用docker制作zookeeper镜像
    java BIO模型demo
    IDEA中语句添加try....catch..语句块
    线程的几种创建方式
    海豚调度Dolphinscheduler源码分析（四）
    @PostConstruct注解
    zookeeper常用命令
  • 原文地址：https://www.cnblogs.com/hfultrastrong/p/7367488.html
Copyright © 2020-2023  润新知