用户登录(JDBC+)
用户登录案例需求：
1.编写login.html登录页面
username & password 两个输入框
2.使用Druid数据库连接池技术,操作mysql，day14数据库中user表
3.使用JdbcTemplate技术封装JDBC
4.登录成功跳转到SuccessServlet展示：登录成功！用户名,欢迎您
5.登录失败跳转到FailServlet展示：登录失败，用户名或密码错误
1.创建项目，导入html页面，配置文件，jar包
<!DOCTYPE html>
<html lang="en">
<head>
<meta charset="UTF-8">
<title>Title</title>
</head>
<body>
<form action="/day14/LoginServlet" method="post">
用户名:<input type="text" name="username"> <br>
密码:<input type="password" name="password"><br>
<input type="submit" value="登录">
</form>
</body>
</html>
2.需要的配置文件druid.properties
driverClassName=com.mysql.jdbc.Driver
url=jdbc:mysql://localhost:3306/day14
username=root
password=123456
initialSize=5
maxActive=10
maxWait=3000
3.需要的jar包
spring-tx-5.0.0.RELEASE.jar
commons-beanutils-1.8.0.jar
commons-logging-1.2.jar
druid-1.0.9.jar
mchange-commons-java-0.2.12.jar
mysql-connector-java-5.1.37-bin.jar
spring-beans-5.0.0.RELEASE.jar
spring-core-5.0.0.RELEASE.jar
spring-jdbc-5.0.0.RELEASE.jar
4.数据库Mysql
CREATE TABLE USER(
id INT PRIMARY KEY AUTO_INCREMENT,
username VARCHAR(32) UNIQUE NOT NULL,
PASSWORD VARCHAR(32) NOT NULL
);
5.创建实体类 domain文件夹下面
package com.itcsl.domain;
/*
用户的实体类
*/
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;
}
@Override
public String toString() {
return "User{" +
"id=" + id +
", username='" + username + '\'' +
", password='" + password + '\'' +
'}';
}
}
6.创建包Utils,编写工具类JDBCUtils
package com.itcsl.util;
import com.alibaba.druid.pool.DruidDataSourceFactory;
import javax.sql.DataSource;
import java.io.IOException;
import java.io.InputStream;
import java.net.URL;
import java.sql.Connection;
import java.sql.SQLException;
import java.util.Properties;
/**
* JDBC的工具类，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ClassLoad加载配置文件，获取字节输入流
InputStream inputStream = JDBCUtils.class.getClassLoader().getResourceAsStream("druid.properties");
pro.load(inputStream);
//2.初始化连接池
ds=DruidDataSourceFactory.createDataSource(pro);
} catch (IOException e) {
e.printStackTrace();
} catch (Exception e) {
e.printStackTrace();
}
}
/**
* 获取连接池对象
*/
public static DataSource getDataSource(){
return ds;
}
/**
* 获取连接Connection对象
*/
public static Connection getConnection() throws SQLException {
return ds.getConnection();
}
}
7.创建包cn.itcast.dao,创建类UserDao,提供login方法
package com.itcsl.dao;
import com.itcsl.domain.User;
import com.itcsl.util.JDBCUtils;
import org.springframework.dao.DataAccessException;
import org.springframework.jdbc.core.BeanPropertyRowMapper;
import org.springframework.jdbc.core.JdbcTemplate;
/*
操作数据库中User表的类
*/
public class UserDao {
//声明JDBCTemplate对象公用
private JdbcTemplate template=new JdbcTemplate(JDBCUtils.getDataSource());
/**
* 登陆方法
* @param loginUser 只有用户名和密码
* @return 包含用户全部数据,没有查询到，返回null值
*/
public User login(User loginUser){
try {
//1.编写sql
String sql="SELECT * FROM USER WHERE username=? AND PASSWORD=?";
//2.调用方法
User user = template.queryForObject(sql,
new BeanPropertyRowMapper<User>(User.class),
loginUser.getUsername(), loginUser.getPassword());
return user;
}catch (DataAccessException e)
{
e.printStackTrace();//记录日志
return null;
}
}
}
8.编写LoginServlet类
package com.itcsl.web.servlet;
import com.itcsl.dao.UserDao;
import com.itcsl.domain.User;
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 java.io.IOException;
import java.lang.reflect.InvocationTargetException;
import java.util.Map;
@WebServlet("/LoginServlet")
public class LoginServlet extends HttpServlet {
@Override
protected void doGet(HttpServletRequest req, HttpServletResponse resp) throws ServletException, IOException {
//1.设置编码
req.setCharacterEncoding("utf-8");
/*
//2.获取请求参数
String username = req.getParameter("username");
String password = req.getParameter("password");
//3.封装User对象
User loginUser = new User();
loginUser.setUsername(username);
loginUser.setPassword(password);
*/
//2.获取所有请求参数
Map<String, String[]> map = req.getParameterMap();
//3/创建一个User对象
User loginUser = new User();
//3.2使用BeanUtils封装
try {
//import org.apache.commons.beanutils.BeanUtils;
BeanUtils.populate(loginUser,map);
} catch (IllegalAccessException e) {
e.printStackTrace();
} catch (InvocationTargetException e) {
e.printStackTrace();
}
//4.调用UserDao的login方法
UserDao dao = new UserDao();
User user = dao.login(loginUser);
//5.判断user
if (user!=null){
//登录成功
req.setAttribute("user",user);
req.getRequestDispatcher("/successServlet").forward(req,resp);
}else{
//登陆失败
req.getRequestDispatcher("/failServlet").forward(req,resp);
}
}
@Override
protected void doPost(HttpServletRequest req, HttpServletResponse resp) throws ServletException, IOException {
this.doGet(req, resp);
}
}
9.编写failServlet类
package com.itcsl.web.servlet;
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("/failServlet")
public class failServlet extends HttpServlet {
protected void doPost(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException {
//给页面写一句话
//设置编码
response.setContentType("text/html;charset=utf-8");
response.getWriter().write("登陆失败，用户名或密码错误");
}
protected void doGet(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException {
this.doPost(request,response);
}
}
10.编写successServlet类
package com.itcsl.web.servlet;
import com.itcsl.domain.User;
import javax.servlet.RequestDispatcher;
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("/successServlet")
public class successServlet extends HttpServlet {
protected void doPost(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException {
User user = (User) request.getAttribute("user");
if (user!=null){
//给页面写一句话
//设置编码
response.setContentType("text/html;charset=utf-8");
response.getWriter().write("登陆成功，"+user.getUsername()+"欢迎你");
}
}
protected void doGet(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException {
this.doPost(request,response);
}
}
简化的数据封装
public class BeanUtilsTest {
@Test
public void test(){
User user = new User();
try {
BeanUtils.setProperty(user,"username","zhangsan");
} catch (IllegalAccessException e) {
e.printStackTrace();
} catch (InvocationTargetException e) {
e.printStackTrace();
}
System.out.println(user);
}
}
最好能够有测试类
package com.itcsl.test;
import com.itcsl.dao.UserDao;
import com.itcsl.domain.User;
import org.junit.Test;
public class UserDaoTest {
@Test
public void testLogin(){
User loginuser = new User();
loginuser.setUsername("admin");
loginuser.setPassword("123");
UserDao dao = new UserDao();
User user = dao.login(loginuser);
System.out.println(user);
}
}
每个人都是在努力的路上，别因为别人的误解而放弃,,术业有专攻，如是而已。
