项目学习 —— 注册和登录（1）
一. 创建动态Web工程
参考：https://blog.csdn.net/Archer__13/article/details/123388390
①scr目录存放自己编写的java代码，并在src下创建以下目录；
②web目录存放web工程的资源文件，例如：html页面、css文件、js文件等，将写好的web页面放到该目录下（首页、用户登录页面、用户注册页面）；
③WEB-INF目录是受服务器保护的目录，浏览器无法直接访问此目录的内容；
④在WEB-INF目录下创建一个lib目录用来存放所需要的第三方jar包；
二. 编写登录和注册页面
1. index.jsp页面
<%@ page contentType="text/html;charset=UTF-8" language="java" %>
首页
2.login.jsp页面
<%@ page contentType="text/html;charset=UTF-8" language="java" %>
登录
3.regist.html页面
<%@ page contentType="text/html;charset=UTF-8" language="java" %>
注册
三. 创建数据库和表
创建一个数据库studyproject，在该数据库下创建一个user表
create table user{
id int primary key auto_increment,
username varchar(20) not null unique,
password varchar(32) not null,
email varchar(200)
};
insert into user(username,password,email) values('admin','admin','[email protected]');四. 编写数据库表对应的JavaBean对象
在pojo包下创建User类
package server.pojo;
public class User {
private Integer id;
private String username;
private String password;
private String email;
public Integer getId() {
return id;
}
public void setId(Integer 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;
}
public String getEmail() {
return email;
}
public void setEmail(String email) {
this.email = email;
}
@Override
public String toString() {
return "User{" +
"id=" + id +
", username='" + username + '\'' +
", password='" + password + '\'' +
", 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;
}
}五. 连接数据库（utils）
1. 创建jdbc.properties文件，将其放在src下(必须是src目录下第一级)，文件内容为：
url=jdbc:mysql://localhost:3306/studyproject
username=root
password=123456
driverClassName=com.mysql.jdbc.Driver
initialSize=10
maxActive=102. 在utils包下创建一个工具类JdbcUtils.java文件，用来连接数据库
package server.utils;
import com.alibaba.druid.pool.DruidDataSourceFactory;
import javax.sql.DataSource;
import java.io.InputStream;
import java.sql.Connection;
import java.sql.SQLException;
import java.util.Properties;
public class JdbcUtils {
private static DataSource source;
static{
try {
Properties properties = new Properties();
//读取jdbc.properties属性
InputStream is = JdbcUtils.class.getClassLoader().getResourceAsStream("jdbc.properties");
//从流中加载数据
properties.load(is);
//创建数据库连接池
source = DruidDataSourceFactory.createDataSource(properties);
} catch (Exception e) {
e.printStackTrace();
}
}
//获取连接
public static Connection getConnection() {
Connection conn = null;
try {
conn = source.getConnection();
} catch (SQLException e) {
e.printStackTrace();
}
return conn;
}
//关闭连接
public static void closeResource(Connection conn){
try {
if(conn != null){
conn.close();
}
} catch (SQLException e) {
e.printStackTrace();
}
}
}六. Dao持久层 —— 操作数据库
1. 在dao.impl包下编写BaseDao类，用来操作数据库（更新、查询）
package server.dao.impl;
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 server.utils.JdbcUtils;
import java.sql.Connection;
import java.util.List;
public abstract class BaseDao {
//使用dbutils操作数据库
private QueryRunner queryRunner = new QueryRunner();
//更新数据
public int updateData(String sql, Object ... args) {
Connection conn = JdbcUtils.getConnection();
try {
return queryRunner.update(conn, sql, args);
} catch (Exception e) {
e.printStackTrace();
}finally {
JdbcUtils.closeResource(conn);
}
return -1;
}
//返回一条数据
public T queryOneData(Class type,String sql, Object ... args){
Connection conn = JdbcUtils.getConnection();
try {
return queryRunner.query(conn,sql,new BeanHandler(type),args);
} catch (Exception e) {
e.printStackTrace();
}finally {
JdbcUtils.closeResource(conn);
}
return null;
}
//返回多条数据
public List queryList(Class type, String sql, Object ... args){
Connection conn = JdbcUtils.getConnection();
try {
return queryRunner.query(conn,sql,new BeanListHandler(type),args);
} catch (Exception e) {
e.printStackTrace();
}finally {
JdbcUtils.closeResource(conn);
}
return null;
}
//返回一个值(一行或一列)
public Object querySingleValues(String sql, Object ... args){
Connection conn = JdbcUtils.getConnection();
try {
return queryRunner.query(conn,sql,new ScalarHandler(),args);
} catch (Exception e) {
e.printStackTrace();
}finally {
JdbcUtils.closeResource(conn);
}
return null;
}
} 2. 在dao包下编写UserDao接口，用来查询数据库中的用户信息和将用户信息保存到数据库中
package server.dao;
import server.pojo.User;
public interface UserDao {
//根据用户名查询用户信息，如果返回null说明没有这个用户
public User queryUserByUsername(String username);
//根据用户名和密码查询用户信息，如果返回null说明用户名或密码错误
public User queryUserByUsernameAndPassword(String username,String password);
//保存用户信息
public int saveUser(User user);
}3. 在dao.impl包下编写一个UserDaoImpl类，继承BaseDao类并实现UserDao接口
package server.dao.impl;
import server.dao.UserDao;
import server.pojo.User;
public class UserDaoImpl extends BaseDao implements UserDao {
@Override
public User queryUserByUsername(String username) {
String sql = "select id, username, password, email from user where username = ?";
return queryOneData(User.class,sql,username);
}
@Override
public User queryUserByUsernameAndPassword(String username, String password) {
String sql = "select id, username, password, email from user where username = ? and password = ?";
return queryOneData(User.class,sql,username,password);
}
@Override
public int saveUser(User user) {
String sql = "insert into user(username,password,email) values(?,?,?)";
return updateData(sql,user.getUsername(),user.getPassword(),user.getEmail());
}
}七. Service业务层 —— 注册和登录
1. 在Service包下编写UserService接口，实现用户注册和登录
package server.service;
import server.pojo.User;
public interface UserService {
//用户注册，如果用户名已存在，则需要重新注册一个新的用户名（用户名不可以重复）
public void registUser(User user);
//用户登录，如果登录失败会返回null
public User login(User user);
//判断用户名是否存在，返回true表示用户名存在，返回flase表示用户名可用
public boolean existUsername(String username);
}2. 在service.impl包下编写UserServiceImpl类来实现UserService接口。
package server.service.impl;
import server.dao.UserDao;
import server.dao.impl.UserDaoImpl;
import server.pojo.User;
import server.service.UserService;
public class UserServiceImpl implements UserService {
private UserDao userDao = new UserDaoImpl();
@Override
public void registUser(User user) {
userDao.saveUser(user);
}
@Override
public User login(User user) {
return userDao.queryUserByUsernameAndPassword(user.getUsername(),user.getPassword());
}
@Override
public boolean existUsername(String username) {
if(userDao.queryUserByUsername(username) == null){
return false;
}else {
return true;
}
}
}八. Web层 —— 实现Servlet程序
Servlet程序用于接收客户端请求然后调用Service层的服务来执行
1. 接收请求的注册信息
①在web目录下编写RegistServlet类来实现
package server.web;
import server.pojo.User;
import server.service.UserService;
import server.service.impl.UserServiceImpl;
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 java.io.IOException;
@WebServlet("/registServlet")
public class RegistServlet extends HttpServlet {
private UserService userService = new UserServiceImpl();
@Override
protected void doPost(HttpServletRequest req, HttpServletResponse resp) throws ServletException, IOException {
//1.获取客户端的请求
String username = req.getParameter("username");
String password = req.getParameter("password");
String email = req.getParameter("email");
//2.用户注册
if(userService.existUsername(username)){
System.out.println("用户名" + username + "已存在");
req.getRequestDispatcher("pages/user/regist.jsp").forward(req,resp); //跳转到注册页面
}else{
userService.registUser(new User(null,username,password,email));
req.getRequestDispatcher("index.jsp").forward(req,resp); //跳转到首页
System.out.println("注册成功");
}
}
}2. 接收请求的登录信息
①在web目录下编写RegistServlet类来实现
package server.web;
import server.pojo.User;
import server.service.UserService;
import server.service.impl.UserServiceImpl;
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 java.io.IOException;
@WebServlet("/loginServlet")
public class LoginServlet extends HttpServlet {
private UserService userService = new UserServiceImpl();
@Override
protected void doPost(HttpServletRequest req, HttpServletResponse resp) throws ServletException, IOException {
//1.获取客户端的请求
String username = req.getParameter("username");
String password = req.getParameter("password");
//2.用户登录
User loginUser = userService.login(new User(null,username,password,null));
if(loginUser == null){
//登录失败，跳回登录页面
System.out.println("登录失败");
req.getRequestDispatcher("pages/user/login.jsp").forward(req,resp);
}else{
//登录成功，跳到首页index.jsp
System.out.println("登录成功");
req.getRequestDispatcher("index.jsp").forward(req,resp);
}
}
}