登陆案例
前言
这是我写的第一篇博客，可能有的地方写的不太好，希望有大神能够指点，同时有看到不懂的同学可以把你的疑惑私信给我，我将尽我所能解答你。
简单的需求分析
需要的jar包
登录的JSP界面
<%--
Created by IntelliJ IDEA.
User: yaoch
Date: 2020/3/8
Time: 14:16
To change this template use File | Settings | File Templates.
--%>
<%@ page contentType="text/html;charset=UTF-8" language="java" %>
<!DOCTYPE html>
<html lang="zh-CN">
<head>
<meta charset="utf-8"/>
<meta http-equiv="X-UA-Compatible" content="IE=edge"/>
<meta name="viewport" content="width=device-width, initial-scale=1"/>
<title>管理员登录</title>
<!-- 1. 导入CSS的全局样式 -->
<link href="css/bootstrap.min.css" rel="stylesheet">
<!-- 2. jQuery导入，建议使用1.9以上的版本 -->
<script src="js/jquery-2.1.0.min.js"></script>
<!-- 3. 导入bootstrap的js文件 -->
<script src="js/bootstrap.min.js"></script>
<script type="text/javascript">
</script>
<script type="text/javascript">
//切换验证码
function refreshCode() {
//获取验证码的图片对象
var vcode= document.getElementById("vcode");
vcode.src="${pageContext.request.contextPath}/CheckCodeServlet?"+new Date().getTime();
}
</script>
</head>
<body>
<div class="container" style="width: 400px;">
<h3 style="text-align: center;">管理员登录</h3>
<form action="${pageContext.request.contextPath}/LoginServlet" method="post">
<div class="form-group">
<label for="user">用户名：</label>
<input type="text" name="username" class="form-control" id="user" placeholder="请输入用户名"/>
</div>
<div class="form-group">
<label for="password">密码：</label>
<input type="password" name="password" class="form-control" id="password" placeholder="请输入密码"/>
</div>
<div class="form-inline">
<label for="vcode">验证码：</label>
<input type="text" name="verifycode" class="form-control" id="verifycode" placeholder="请输入验证码" style="width: 120px;"/>
<a href="javascript:refreshCode()"><img src="${pageContext.request.contextPath}/CheckCodeServlet" title="看不清点击刷新" id="vcode"/></a>
</div>
<hr/>
<div class="form-group" style="text-align: center;">
<input class="btn btn btn-primary" type="submit" value="登录">
</div>
</form>
<!-- 出错显示的信息框 -->
<div class="alert alert-warning alert-dismissible" role="alert">
<button type="button" class="close" data-dismiss="alert" >
<span>×</span></button>
<strong>${requestScope.get("login_msg")}</strong>
</div>
</div>
</body>
</html>
登录的Servlet——LoginServlet.java
package cn.itcust.web.servlet;
import cn.itcust.domain.User;
import cn.itcust.service.UserService;
import cn.itcust.service.impl.UserServiceImpl;
import org.apache.commons.beanutils.BeanUtils;
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 javax.servlet.http.HttpSession;
import java.io.IOException;
import java.lang.reflect.InvocationTargetException;
import java.util.Map;
@WebServlet("/LoginServlet")
public class LoginServlet extends HttpServlet {
protected void doPost(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException {//
//设置编码
request.setCharacterEncoding("utf-8");
//获取数据
//验证码
String verifycode = request.getParameter("verifycode");
//校验验证码
HttpSession session = request.getSession();
String checkCode_session = (String) session.getAttribute("checkCode_session");
session.removeAttribute("checkCode_session"); //获取验证码后删除 确保验证码一次性
if(!verifycode.equalsIgnoreCase(checkCode_session)){
request.setAttribute("login_msg","验证码错误！！");
request.getRequestDispatcher("/login.jsp").forward(request,response);
return;
}
Map<String, String[]> map = request.getParameterMap();
//封装user对象
User user = new User();
try {
BeanUtils.populate(user, map);
} catch (IllegalAccessException e) {
e.printStackTrace();
} catch (InvocationTargetException e) {
e.printStackTrace();
}
//调用service查询
UserService service = new UserServiceImpl();
User loginuser= service.login(user);
//判断是否登陆成功
if(loginuser!=null){
session.setAttribute("user",loginuser);
response.sendRedirect(request.getContextPath()+"/index.jsp");
}else {
request.setAttribute("login_msg","用户名或密码错误！！！");
request.getRequestDispatcher("/login.jsp").forward(request,response);
}
}
protected void doGet(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException {
this.doPost(request, response);
}
}
登录的UserService
1.UserService接口
package cn.itcust.service;
import cn.itcust.domain.PageBean;
import cn.itcust.domain.User;
import java.util.List;
import java.util.Map;
/*
* 用户管理的业务接口
* */
public interface UserService {
/*登录方法*/
public User login(User user);
}
- 实现User Service接口
package cn.itcust.service.impl;
import cn.itcust.dao.UserDao;
import cn.itcust.dao.impl.UserDaoImpl;
import cn.itcust.domain.PageBean;
import cn.itcust.domain.User;
import cn.itcust.service.UserService;
import java.util.List;
import java.util.Map;
public class UserServiceImpl implements UserService {
private UserDao dao = new UserDaoImpl();
@Override
public User login(User user) {
return dao.findUserByUsernameAndPassword(user.getUsername(), user.getPassword());
}
}
这里使用的是面向接口的编程方法，降低了降低了程序的耦合性，易拓展，便于维护
登录的UserDao
1.UserDao接口
package cn.itcust.dao;
import cn.itcust.domain.User;
import java.util.List;
import java.util.Map;
/*
* 用户操作的Dao
* */
public interface UserDao {
public User findUserByUsernameAndPassword(String username, String password);
}
实现UserDao接口
package cn.itcust.dao.impl;
import cn.itcust.dao.UserDao;
import cn.itcust.domain.User;
import cn.itcust.util.JDBCUtils;
import org.springframework.dao.DataAccessException;
import org.springframework.jdbc.core.BeanPropertyRowMapper;
import org.springframework.jdbc.core.JdbcTemplate;
import java.util.ArrayList;
import java.util.List;
import java.util.Map;
import java.util.Set;
public class UserDaoImpl implements UserDao {
private JdbcTemplate template = new JdbcTemplate(JDBCUtils.getDataSouce());
@Override
public User findUserByUsernameAndPassword(String username, String password) {
try {
String sql = "select * from user where username = ? and password = ?";
User users = template.queryForObject(sql, new BeanPropertyRowMapper<User>(User.class), username, password);
return users;
} catch (DataAccessException e) {
e.printStackTrace();
return null;
}
}
}
User实体类
package cn.itcust.domain;
public class User {
private int id ;
private String name;
private String gender;
private int age ;
private String address ;
private String qq;
private String email;
private String username;
private String password;
@Override
public String toString() {
return "User{" +
"id=" + id +
", name='" + name + '\'' +
", gender='" + gender + '\'' +
", age=" + age +
", address='" + address + '\'' +
", qq='" + qq + '\'' +
", email='" + email + '\'' +
", username='" + username + '\'' +
", password='" + password + '\'' +
'}';
}
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;
}
public int getId() {
return id;
}
public void setId(int id) {
this.id = id;
}
public String getName() {
return name;
}
public void setName(String name) {
this.name = name;
}
public String getGender() {
return gender;
}
public void setGender(String gender) {
this.gender = gender;
}
public int getAge() {
return age;
}
public void setAge(int age) {
this.age = age;
}
public String getAddress() {
return address;
}
public void setAddress(String address) {
this.address = address;
}
public String getQq() {
return qq;
}
public void setQq(String qq) {
this.qq = qq;
}
public String getEmail() {
return email;
}
public void setEmail(String email) {
this.email = email;
}
}
JDBC工具类
package cn.itcust.util;
import com.alibaba.druid.pool.DruidDataSourceFactory;
import javax.sql.DataSource;
import java.io.IOException;
import java.io.InputStream;
import java.sql.Connection;
import java.sql.SQLException;
import java.util.Properties;
/*
* JDBC工具类 使用Durid连接池
* */
public class JDBCUtils {
private static DataSource ds ;
static {
try {
//1.加载配置文件
Properties pro = new Properties();
//使用class Loader加载配置文件，获取字节输入流
InputStream is = JDBCUtils.class.getClassLoader().getResourceAsStream("druid.properties");
pro.load(is);
//2.初始化连接池对象
ds= DruidDataSourceFactory.createDataSource(pro);
} catch (IOException e) {
e.printStackTrace();
}
catch (Exception e) {
e.printStackTrace();
}
}
/**
* 获取连接池对象
**/
public static DataSource getDataSouce (){
return ds;
}
/*
*获取连接池Connection对象
* */
public static Connection getConnection() throws SQLException{
return ds.getConnection();
}
}
druid配置文件
# druid.properties文件的配置
driverClassName=com.mysql.cj.jdbc.Driver
url=jdbc:mysql://127.0.0.1:3306/day17?serverTimezone=UTC&characterEncoding=utf-8&useSSL=false
# Mysql账号
username=
# Mysql密码
password=
# 初始化连接数量
initialSize=5
# 最大连接数
maxActive=10
# 最大超时时间
maxWait=3000
filters=stat
timeBetweenEvictionRunsMillis=60000
minEvictableIdleTimeMillis=300000
validationQuery=SELECT 1
testWhileIdle=true
testOnBorrow=false
testOnReturn=false
poolPreparedStatements=false
maxPoolPreparedStatementPerConnectionSize=200
