用户登录Demo
1.创建 JavaEE book 项目
2.导入相关静态资源至webapp 目录下
3.创建数据库
DROP TABLE IF EXISTS book;
CREATE DATABASE book;
USE book;
CREATE TABLE t_user(
`id` INT PRIMARY KEY AUTO_INCREMENT,
`username` VARCHAR(20) NOT NULL UNIQUE,
`password` VARCHAR(32) NOT NULL ,
`email` VARCHAR(200)
);
INSERT INTO t_user(`username`,`password`,`email`) VALUES('admin','admin','[email protected]');
SELECT * FROM t_user;
4.编写数据库表需要的 JavaBean 对象
package com.atguigu.pojo;
package com.atguigu.pojo;
/**
* @author: sjmp1573
* @date: 2022/7/17 17:48
* @description:
*/
public class User {
private Integer id;
private String username;
private String password;
private String email;
public Integer getId() {
return id;
}
public String getUsername() {
return username;
}
public String getPassword() {
return password;
}
public String getEmail() {
return email;
}
public void setId(Integer id) {
this.id = id;
}
public void setUsername(String username) {
this.username = username;
}
public void setPassword(String password) {
this.password = password;
}
public void setEmail(String email) {
this.email = email;
}
public User() {
}
public User(Integer id, String username, String password, String email) {
this.id = id;
this.username = username;
this.password = password;
this.email = email;
}
@Override
public String toString() {
return "User{" +
"id=" + id +
", username='" + username + ''' +
", password='" + password + ''' +
", email='" + email + ''' +
'}';
}
}
5.编写DAO持久层
为book 模块添加依赖。
WEB-INF 外部无法访问，可以放 jar包，数据库的配置。
编写 JDBCUtils 工具类
package com.atguigu;
import com.alibaba.druid.pool.DruidDataSource;
import com.alibaba.druid.pool.DruidDataSourceFactory;
import java.io.InputStream;
import java.sql.Connection;
import java.sql.SQLException;
import java.util.Properties;
/**
* @author: sjmp1573
* @date: 2022/7/17 21:12
* @description:
*/
public class JdbcUtils {
private static DruidDataSource dataSource;
static {
try {
Properties properties = new Properties();
InputStream inputStream = JdbcUtils.class.getClassLoader().getResourceAsStream("jdbc.properties");
properties.load(inputStream);
dataSource = (DruidDataSource) DruidDataSourceFactory.createDataSource(properties);
} catch (Exception e) {
e.printStackTrace();
}
}
/**
* 获取数据库连接池中的连接
*
* @return 如果如果返回null, 说明获取连接失败<br />有值就是获取连接成功
*/
public static Connection getConnection() {
Connection conn = null;
try {
conn = dataSource.getConnection();
} catch (SQLException e) {
e.printStackTrace();
}
return conn;
}
/**
* 关闭连接，放回数据库
* @param conn
* */
public static void close(Connection conn) {
if (conn != null) {
try {
conn.close();
} catch (SQLException e) {
e.printStackTrace();
}
}
}
}
编写 jdbc.properties配置文件
src/main/resources/jdbc.properties
username=root
password=***********
url=jdbc:mysql://localhost:3306/book
driverClassName=com.mysql.jdbc.Driver
initialSize=5
maxActive=10
6.编写BaseDAO
package com.atguigu.dao.impl;
import com.atguigu.JdbcUtils;
import org.apache.commons.dbutils.QueryRunner;
import org.apache.commons.dbutils.handlers.BeanHandler;
import org.apache.commons.dbutils.handlers.BeanListHandler;
import org.apache.commons.dbutils.handlers.ScalarHandler;
import java.sql.Connection;
import java.sql.SQLException;
import java.util.List;
/**
* @author: sjmp1573
* @date: 2022/7/17 22:00
* @description:
*/
public abstract class BaseDao {
private QueryRunner queryRunner = new QueryRunner();
/**
* update() 方法用来执行：InsertUpdateDelete语句
*
* @return 如果返回-1,说明执行失败<br/>返回其他表示影响的行数
*/
public int update(String sql, Object args) {
Connection connection = JdbcUtils.getConnection();
try {
return queryRunner.update(connection, sql, args);
} catch (SQLException e) {
e.printStackTrace();
} finally {
JdbcUtils.close(connection);
}
return -1;
}
/**
* 查询返回一个javaBean的sql语句
*
* @param type 返回的对象类型
* @param sql 执行的sql语句
* @param args sql对应的参数值
* @param <T> 返回的类型的泛型
* @return
*/
public <T> T queryForOne(Class<T> type, String sql, Object... args) {
Connection conn = JdbcUtils.getConnection();
try {
return queryRunner.query(conn, sql, new BeanHandler<T>(type), args);
} catch (SQLException e) {
e.printStackTrace();
} finally {
JdbcUtils.close(conn);
}
return null;
}
/**
* 查询返回多个javaBean的sql语句
*
* @param type 返回的对象类型
* @param sql 执行的sql语句
* @param args sql对应的参数值
* @param <T> 返回的类型的泛型
* @return
*/
public <T> List<T> queryForList(Class<T> type, String sql, Object... args) {
Connection con = JdbcUtils.getConnection();
try {
return queryRunner.query(con, sql, new BeanListHandler<T>(type), args);
} catch (SQLException e) {
e.printStackTrace();
} finally {
JdbcUtils.close(con);
}
return null;
}
/**
* 执行返回一行一列的sql语句
*
* @param sql 执行的sql语句
* @param args sql对应的参数值
* @return
*/
public Object queryForSingleValue(String sql, Object... args) {
Connection conn = JdbcUtils.getConnection();
try {
return queryRunner.query(conn, sql, new ScalarHandler(), args);
} catch (SQLException e) {
e.printStackTrace();
} finally {
JdbcUtils.close(conn);
}
return null;
}
}
7. 编写Dao层（ UserDaoImpl 和 UserDao）
package com.atguigu.dao.impl;
import com.atguigu.dao.UserDao;
import com.atguigu.pojo.User;
public class UserDaoImpl extends BaseDao implements UserDao {
@Override
public User queryUserByUsername(String username) {
String sql = "select `id`,`username`,`password`,`email` from t_user where username = ?";
return queryForOne(User.class, sql, username);
}
@Override
public User queryUserByUsernameAndPassword(String username, String password) {
String sql = "select `id`,`username`,`password`,`email` from t_user where username = ? and password = ?";
return queryForOne(User.class, sql, username,password);
}
@Override
public int saveUser(User user) {
String sql = "insert into t_user(`username`,`password`,`email`) values(?,?,?)";
return update(sql, user.getUsername(),user.getPassword(),user.getEmail());
}
}
然后测试
8.编写Service层（UserServiceImpl 和 UserService）
package com.atguigu.service.impl;
import com.atguigu.dao.UserDao;
import com.atguigu.dao.impl.UserDaoImpl;
import com.atguigu.pojo.User;
import com.atguigu.service.UserService;
/**
* @author: sjmp1573
* @date: 2022/7/17 23:03
* @description:
*/
public class UserServiceImpl implements UserService {
UserDao userDao = new UserDaoImpl();
@Override
public boolean registerUser(User user) {
int i = userDao.saveUser(user);
return i == 1;
}
@Override
public boolean login(User user) {
User user1 = userDao.queryUserByUsernameAndPassword(user.getUsername(), user.getPassword());
return user1 != null;
}
@Override
public boolean exitsUsername(String username) {
User user = userDao.queryUserByUsername(username);
return user != null;
}
}
9.编写用户注册功能（web层）
package com.atguigu.web;
import com.atguigu.pojo.User;
import com.atguigu.service.UserService;
import com.atguigu.service.impl.UserServiceImpl;
import javax.servlet.ServletException;
import javax.servlet.http.HttpServlet;
import javax.servlet.http.HttpServletRequest;
import javax.servlet.http.HttpServletResponse;
import java.io.IOException;
/**
* @author: sjmp1573
* @date: 2022/7/17 23:35
* @description:
*/
public class RegisterServlet extends HttpServlet {
private UserService userService = new UserServiceImpl();
@Override
protected void doPost(HttpServletRequest req, HttpServletResponse resp) throws ServletException, IOException {
// 1.获取请求参数
String username = req.getParameter("username");
String password = req.getParameter("password");
String email = req.getParameter("email");
String code = req.getParameter("code");
// 2.检查验证码是否正确
if ("abcde".equalsIgnoreCase(code)) {
// 3.检查用户名是否可用
if (userService.exitsUsername(username)) {
System.out.println("用户名[" + username + "]已存在!");
req.getRequestDispatcher("/pages/user/regist.html").forward(req, resp);
} else {
userService.registerUser(new User(null, username, password, email));
// 跳到注册成功页面 regist_success.html
req.getRequestDispatcher("/pages/user/regist_success.html").forward(req, resp);
}
} else {
System.out.println("验证码[" + code + "]错误");
req.getRequestDispatcher("/pages/user/regist.html").forward(req, resp);
}
}
}