DAO三层架构及工厂模式
2024-10-08 15:17:54
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);
}
}
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