DAO三层架构及工厂模式

目录结构

1.在domain包中创建User实体类

package com.rick.domain;

import java.util.Date;

public class User {
	private int id;
	private String name;
	private Date birthday;
	private float money;

	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 Date getBirthday() {
		return birthday;
	}

	public void setBirthday(Date birthday) {
		this.birthday = birthday;
	}

	public float getMoney() {
		return money;
	}

	public void setMoney(float money) {
		this.money = money;
	}
}

2.在Dao包中创建User的实现接口

package com.rick.dao;

import com.rick.domain.User;

public interface UserDao {
	public void addUser(User user);

	public User getUser(int userId);

	public User findUser(String loginName, String password);

	public void update(User user);

	public void delete(User user);
}

3.新建一个utils包创建工具类JdbcUtils

package com.rick.utlis;

import java.sql.Connection;
import java.sql.DriverManager;
import java.sql.ResultSet;
import java.sql.SQLException;
import java.sql.Statement;

public final class JdbcUtils {
	private static String url = "jdbc:mysql://localhost:3306/jdbc";
	private static String user = "root";
	private static String password = "";

	private JdbcUtils() {
	}

	static {
		try {
			Class.forName("com.mysql.jdbc.Driver");
		} catch (ClassNotFoundException e) {
			throw new ExceptionInInitializerError(e);
		}
	}

	public static Connection getConnection() throws SQLException {
		return DriverManager.getConnection(url, user, password);
	}

	public static void free(ResultSet rs, Statement st, Connection conn) {
		try {
			if (rs != null)
				rs.close();
		} catch (SQLException e) {
			e.printStackTrace();
		} finally {
			try {
				if (st != null)
					st.close();
			} catch (SQLException e) {
				e.printStackTrace();
			} finally {
				if (conn != null)
					try {
						conn.close();
					} catch (SQLException e) {
						e.printStackTrace();
					}
			}
		}
	}
}

4.在impl中创建接口实现类UserDaoJdbcImpl

package com.rick.dao.impl;

import java.sql.Connection;
import java.sql.PreparedStatement;
import java.sql.ResultSet;
import java.sql.SQLException;
import java.sql.Statement;

import com.rick.dao.UserDao;
import com.rick.domain.User;
import com.rick.utlis.JdbcUtils;

public class UserDaoJdbcImpl implements UserDao {

	public void addUser(User user) {
		Connection conn = null;
		PreparedStatement ps = null;
		ResultSet rs = null;
		try {
			conn = JdbcUtils.getConnection();
			String sql = "insert into user(name,birthday, money) values (?,?,?) ";
			ps = conn.prepareStatement(sql);
			ps.setString(1, user.getName());
			ps.setDate(2, new java.sql.Date(user.getBirthday().getTime()));
			ps.setFloat(3, user.getMoney());
			ps.executeUpdate();
		} catch (SQLException e) {
			throw new DaoException(e.getMessage(), e);
		} finally {
			JdbcUtils.free(rs, ps, conn);
		}
	}

	public void delete(User user) {
		Connection conn = null;
		Statement st = null;
		ResultSet rs = null;
		try {
			conn = JdbcUtils.getConnection();
			st = conn.createStatement();
			String sql = "delete from user where id=" + user.getId();
			st.executeUpdate(sql);
		} catch (SQLException e) {
			throw new DaoException(e.getMessage(), e);
		} finally {
			JdbcUtils.free(rs, st, conn);
		}

	}

	public User findUser(String loginName, String password) {
		Connection conn = null;
		PreparedStatement ps = null;
		ResultSet rs = null;
		User user = null;
		try {
			conn = JdbcUtils.getConnection();
			String sql = "select id, name, money, birthday  from user where name=?";
			ps = conn.prepareStatement(sql);
			ps.setString(1, loginName);
			rs = ps.executeQuery();
			while (rs.next()) {
				user = mappingUser(rs);
			}
		} catch (SQLException e) {
			throw new DaoException(e.getMessage(), e);
		} finally {
			JdbcUtils.free(rs, ps, conn);
		}
		return user;
	}

	public User getUser(int userId) {
		Connection conn = null;
		PreparedStatement ps = null;
		ResultSet rs = null;
		User user = null;
		try {
			conn = JdbcUtils.getConnection();
			String sql = "select id, name, money, birthday  from user where id=?";
			ps = conn.prepareStatement(sql);
			ps.setInt(1, userId);
			rs = ps.executeQuery();
			while (rs.next()) {
				user = mappingUser(rs);
			}
		} catch (SQLException e) {
			throw new DaoException(e.getMessage(), e);
		} finally {
			JdbcUtils.free(rs, ps, conn);
		}
		return user;
	}

	private User mappingUser(ResultSet rs) throws SQLException {
		User user = new User();
		user.setId(rs.getInt("id"));
		user.setName(rs.getString("name"));
		user.setMoney(rs.getFloat("money"));
		user.setBirthday(rs.getDate("birthday"));
		return user;
	}

	public void update(User user) {
		Connection conn = null;
		PreparedStatement ps = null;
		ResultSet rs = null;
		try {
			conn = JdbcUtils.getConnection();
			String sql = "update user set name=?, birthday=?, money=? where id=? ";
			ps = conn.prepareStatement(sql);
			ps.setString(1, user.getName());
			ps.setDate(2, new java.sql.Date(user.getBirthday().getTime()));
			ps.setFloat(3, user.getMoney());
			ps.setInt(4, user.getId());
			ps.executeUpdate();
		} catch (SQLException e) {
			throw new DaoException(e.getMessage(), e);
		} finally {
			JdbcUtils.free(rs, ps, conn);
		}
	}

}

5.在dao中创建一个捕获异常类DaoException继承RuntimeException

package com.rick.dao;

public class DaoException extends RuntimeException {

	public DaoException() {
		// TODO Auto-generated constructor stub
	}

	public DaoException(String message) {
		super(message);
		// TODO Auto-generated constructor stub
	}

	public DaoException(Throwable cause) {
		super(cause);
		// TODO Auto-generated constructor stub
	}

	public DaoException(String message, Throwable cause) {
		super(message, cause);
		// TODO Auto-generated constructor stub
	}

	public DaoException(String message, Throwable cause, boolean enableSuppression, boolean writableStackTrace) {
		super(message, cause, enableSuppression, writableStackTrace);
		// TODO Auto-generated constructor stub
	}

}

6.在业务逻辑层service包中创建UserService(模拟，此项目中无用)

package com.rick.service;

import com.rick.dao.UserDao;

public class UserService {
	private UserDao userDao;

	public void regist(com.rick.domain.User user) {
		this.userDao.addUser(user);
		// sendMail.send(user);
	}
}

7.创建daoconfig.properties文件

8.在Dao中创建工厂类DaoFactory

package com.rick.dao;

import java.io.InputStream;
import java.util.Properties;

public class DaoFactory {
	private static UserDao userDao = null;
	private static DaoFactory instance = new DaoFactory();

	private DaoFactory() {
		try {
			Properties prop = new Properties();
			InputStream inStream = DaoFactory.class.getClassLoader()
					.getResourceAsStream("daoconfig.properties");
			prop.load(inStream);
			String userDaoClass = prop.getProperty("userDaoClass");
			Class clazz = Class.forName(userDaoClass);
			userDao = (UserDao) clazz.newInstance();
		} catch (Throwable e) {
			throw new ExceptionInInitializerError(e);
		}
	}

	public static DaoFactory getInstance() {
		return instance;
	}

	public UserDao getUserDao() {
		return userDao;
	}
}

9.测试

package com.rick.dao;

import java.util.Date;

import com.rick.domain.User;

public class UserDaoTest {

	public static void main(String[] args) {
		UserDao userDao = DaoFactory.getInstance().getUserDao();
		// System.out.println(userDao);

		 User user = new User();
		 user.setBirthday(new Date());
		 user.setName("dao name1");
		 user.setMoney(1000.0f);

		 userDao.addUser(user);

		// User u = userDao.findUser(user.getName(), null);
		// System.out.println(u.getId());

//		User u = userDao.getUser(7);
//		u.setMoney(20000.1f);
//		userDao.update(u);

		// User u1 = userDao.getUser(8);
		// userDao.delete(u1);
	}
}