通过web_servlet05 ，打通任督二脉，完成登陆和注册功能，这里面分了两个项目，功能一样，其中一个使用了才c3p0连接池和dbutil框架
Jsp -> view
Servlet -> Ctroller
dao、entity .. -> model
mvc -> view 提交到Ctroller，Ctroller访问model，model把数据返回给Ctroller, Ctroller再放回到jsp页面
1、需求
实现用户的登陆和注册功能
2、code
1）UserDao
package com.alex.web.dao;
import com.alex.web.entity.User;
public interface UserDao {
public User login(String username,String userpswd) throws Exception;
}
2）UserDaoImpl
package com.alex.web.dao;
import java.sql.Connection;
import java.sql.PreparedStatement;
import java.sql.ResultSet;
import com.alex.web.entity.User;
import com.alex.web.util.DBUtil;
public class UserDaoImpl implements UserDao {
/**
CREATE TABLE t_user(
id INT PRIMARY KEY AUTO_INCREMENT,
username VARCHAR(32),
password VARCHAR(64),
email VARCHAR(128),
age INT
);
*/
@Override
public User login(String username, String userpswd) throws Exception {
Connection connection = null ;
ResultSet resultSet = null ;
PreparedStatement prepareStatement = null;
User user = null ;
try {
connection = DBUtil.getConnection();
String sql = "select * from t_user where username=? and password=?";
prepareStatement = connection.prepareStatement(sql);
prepareStatement.setObject(1, username);
prepareStatement.setObject(2, userpswd);
resultSet = prepareStatement.executeQuery();
if (resultSet.next()) {
user = new User();
user.setId(resultSet.getInt("id"));
user.setUsername(resultSet.getString("username"));
user.setPassword(resultSet.getString("password"));
user.setEmail(resultSet.getString("email"));
user.setAge(resultSet.getInt("age"));
}
} catch (Exception e) {
e.printStackTrace();
throw e ;
} finally{
DBUtil.closeConnection(resultSet,prepareStatement,connection);
}
return user;
}
}
3）User
package com.alex.web.entity;
public class User {
private Integer id;
private String username;
private String password;
private String email;
private int age;
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;
}
public int getAge() {
return age;
}
public void setAge(int age) {
this.age = age;
}
@Override
public String toString() {
return "User [id=" + id + ", username=" + username + ", password=" + password + ", email=" + email + ", age="
+ age + "]";
}
}
4）LoginServlet
package com.alex.web.servlet;
import java.io.IOException;
import javax.servlet.ServletException;
import javax.servlet.http.HttpServlet;
import javax.servlet.http.HttpServletRequest;
import javax.servlet.http.HttpServletResponse;
import com.alex.web.dao.UserDao;
import com.alex.web.dao.UserDaoImpl;
import com.alex.web.entity.User;
/**
* Servlet作用:处理请求
* 步骤:
* ①获取请求数据.
* ②调用业务层或DAO层方法,完成业务逻辑处理或数据处理.
* ③根据调用的方法获取返回结果,根据结果来进行判断,然后跳转(转发,重定向)到不同页面.
*/
public class LoginServlet extends HttpServlet {
@Override
public void service(HttpServletRequest req, HttpServletResponse resp)
throws ServletException, IOException{
try {
String username = req.getParameter("username");
String passwd = req.getParameter("passwd");
resp.setContentType("text/html;charset=UTF-8");
UserDao userDao = new UserDaoImpl();
User loginUser = userDao.login(username, passwd);
if(loginUser!=null){
req.getRequestDispatcher("/success.jsp").forward(req, resp);
}else{
// http://localhost:8080/WebServlet1/failure.html
resp.sendRedirect(req.getContextPath()+"/failure.jsp");
}
} catch (Exception e) {
e.printStackTrace();
resp.sendRedirect(req.getContextPath()+"/error.jsp");
}
}
}
5）DBUtil
package com.alex.web.util;
import java.io.FileInputStream;
import java.sql.Connection;
import java.sql.DriverManager;
import java.sql.ResultSet;
import java.sql.SQLException;
import java.sql.Statement;
import java.util.Properties;
public class DBUtil {
static String driverClass;
static String url;
static String user;
static String password;
static {
try {
// 加载配置文件
Properties pro = new Properties();
//pro.load(new FileInputStream("src/db.properties"));
// 反射加载读取项目配置文件
pro.load(DBUtil.class.getClassLoader().getResourceAsStream("db.properties"));
// 读取配置文件
driverClass = pro.getProperty("driverClass");
url = pro.getProperty("url");
user = pro.getProperty("username");
password = pro.getProperty("password");
// 1.加载驱动
Class.forName(driverClass);
} catch (Exception e) {
e.printStackTrace();
}
}
/**
* 功能：获取连接 异常抛就行，可根据自己的方式处理异常
*
* @return 可用的连接对象
* @throws IOException
* @throws FileNotFoundException
*/
public static Connection getConnection() throws Exception {
return DriverManager.getConnection(url, user, password);
}
/**
* 功能：关闭资源
*
* @param set
* @param statement
* @param connection
* @throws SQLException
*/
public static void closeConnection(ResultSet set, Statement statement, Connection connection) throws SQLException {
if (set != null)
set.close();
if (statement != null)
statement.close();
if (connection != null)
connection.close();
}
}
6）db.properties
driverClass=com.mysql.jdbc.Driver
url=jdbc:mysql:///test
#url=jdbc:mysql://127.0.0.1:3306/test
#url=jdbc:mysql:///test?rewriteBatchedStatements=true&useServerPrepStmts=false
username=root
password=root
initialSize=5
maxActive=10
3、调试
浏览器端使用F12
服务器端使用小虫子进行断点调试
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