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锁定老帖子 主题：关于DAO设计的一个问题 (讨论)
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发表时间：2007-03-06
假设有两个实体模型User 和 account .
那么在设计DAO的时候: UserDAO里面放只涉及到User信息的数据库操作,AccountDAO里面放只涉及到Account的信息, 涉及到User和Account共同的信息全部放到UserAccountDAO里面. 不知道大家是怎么样设计的 
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发表时间：2007-03-06
方法：
1）在上面添加一个service层 2）直接在某个DAO中操作。 |
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发表时间：2007-03-06
方法：
1）在上面添加一个service层 2）直接在某个DAO中操作。 |
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发表时间：2007-03-06
涉及到共同的信息？难道User和Account是多对多的？不合常理阿？如果你指的是数据库方面的多个操作，应该写成Service
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发表时间：2007-03-06
一对多写了几行代码;改改吧
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发表时间：2007-03-06
包结构为
com.java.client Client.java com.java.dao AccountDao.java AccountDaoImpl.java UserDao.java UserDaoImpl.java DaoFactory.java com.java.db Account.java User.java com.java.service UserService.java ************************************ |
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发表时间：2007-03-06
User 类
/*
* Created on Mar 6, 2007
*
* To change the template for this generated file go to
* Window>Preferences>Java>Code Generation>Code and Comments
*/
package com.java.db;
import java.io.Serializable;
/**
* @author asdf
*
* To change the template for this generated type comment go to
* Window>Preferences>Java>Code Generation>Code and Comments
*/
public class User implements Serializable
{
private int userId;
private String userName;
private String firstName;
private String lastName;
private String nickName;
private String email;
}
Account类
/*
* Created on Mar 6, 2007
*
* To change the template for this generated file go to
* Window>Preferences>Java>Code Generation>Code and Comments
*/
package com.java.db;
import java.io.Serializable;
import java.util.Date;
/**
* @author asdf
*
* To change the template for this generated type comment go to
* Window>Preferences>Java>Code Generation>Code and Comments
*/
public class Account implements Serializable
{
private int accountId;
private int userId;
private String accountType;
private Date createDate;
private Date updateDate;
}
省略get/set方法 |
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发表时间：2007-03-06
AccountDao
/* * Created on Mar 6, 2007 * * To change the template for this generated file go to * Window>Preferences>Java>Code Generation>Code and Comments */ package com.java.dao; import java.util.List;
import com.java.db.Account;
import com.java.db.User;
/**
* @author asdf
*
* To change the template for this generated type comment go to
* Window>Preferences>Java>Code Generation>Code and Comments
*/
public interface AccountDAO
{
public int saveAccount(Account account)throws Exception;
public boolean delAccount(int accountId)throws Exception;
public void updateAccount(Account account)throws Exception;
public Account findAccountByID(int id)throws Exception;
public User findUserByAccountId(int accountId)throws Exception;
public List findAllAccount()throws Exception;
public boolean batchDelAccount(int[] accountId)throws Exception;
}
AccountDaoImpl /*
* Created on Mar 6, 2007
*
* To change the template for this generated file go to
* Window>Preferences>Java>Code Generation>Code and Comments
*/
package com.java.dao;
import java.sql.Connection;
import java.util.List;
import com.java.db.Account;
import com.java.db.User;
/**
* @author asdf
*
* To change the template for this generated type comment go to
* Window>Preferences>Java>Code Generation>Code and Comments
*/
public class AccountDAOImpl implements AccountDAO {
private Connection connection =null;
public AccountDAOImpl(Connection connection) {
this.connection =connection;
// TODO Auto-generated constructor stub
}
/* (non-Javadoc)
* @see com.java.dao.AccountDAO#saveAccount(com.java.db.Account)
*/
public int saveAccount(Account account) {
// TODO Auto-generated method stub
return 0;
}
/* (non-Javadoc)
* @see com.java.dao.AccountDAO#delAccount(int)
*/
public boolean delAccount(int accountId) {
// TODO Auto-generated method stub
return false;
}
/* (non-Javadoc)
* @see com.java.dao.AccountDAO#updateAccount(com.java.db.Account)
*/
public void updateAccount(Account account) {
// TODO Auto-generated method stub
}
/* (non-Javadoc)
* @see com.java.dao.AccountDAO#findAccountByID(int)
*/
public Account findAccountByID(int id) {
// TODO Auto-generated method stub
return null;
}
/* (non-Javadoc)
* @see com.java.dao.AccountDAO#findUserByAccountId(int)
*/
public User findUserByAccountId(int accountId) {
// TODO Auto-generated method stub
return null;
}
/* (non-Javadoc)
* @see com.java.dao.AccountDAO#findAllAccount()
*/
public List findAllAccount() {
// TODO Auto-generated method stub
return null;
}
/* (non-Javadoc)
* @see com.java.dao.AccountDAO#batchDelAccount(int[])
*/
public boolean batchDelAccount(int[] accountId) throws Exception {
// TODO Auto-generated method stub
return false;
}
}
UserDAO 类 /*
* Created on Mar 6, 2007
*
* To change the template for this generated file go to
* Window>Preferences>Java>Code Generation>Code and Comments
*/
package com.java.dao;
import java.util.List;
import com.java.db.User;
/**
* @author asdf
*
* To change the template for this generated type comment go to
* Window>Preferences>Java>Code Generation>Code and Comments
*/
public interface UserDAO
{
public int saveUser(User user)throws Exception;
public boolean delUser(int userId) throws Exception;
public void updateUser(User user) throws Exception;
public User findUserById(int userId) throws Exception;
public List findUserByName(String userName) throws Exception;
public List findAllUser()throws Exception;
public List findAccountByUserId(int userId)throws Exception;
}
UserDAOImpl类 /*
* Created on Mar 6, 2007
*
* To change the template for this generated file go to
* Window>Preferences>Java>Code Generation>Code and Comments
*/
package com.java.dao;
import java.sql.Connection;
import java.util.List;
import com.java.db.Account;
import com.java.db.User;
/**
* @author asdf
*
* To change the template for this generated type comment go to
* Window>Preferences>Java>Code Generation>Code and Comments
*/
public class AccountDAOImpl implements AccountDAO {
private Connection connection =null;
public AccountDAOImpl(Connection connection) {
this.connection =connection;
// TODO Auto-generated constructor stub
}
/* (non-Javadoc)
* @see com.java.dao.AccountDAO#saveAccount(com.java.db.Account)
*/
public int saveAccount(Account account) {
// TODO Auto-generated method stub
return 0;
}
/* (non-Javadoc)
* @see com.java.dao.AccountDAO#delAccount(int)
*/
public boolean delAccount(int accountId) {
// TODO Auto-generated method stub
return false;
}
/* (non-Javadoc)
* @see com.java.dao.AccountDAO#updateAccount(com.java.db.Account)
*/
public void updateAccount(Account account) {
// TODO Auto-generated method stub
}
/* (non-Javadoc)
* @see com.java.dao.AccountDAO#findAccountByID(int)
*/
public Account findAccountByID(int id) {
// TODO Auto-generated method stub
return null;
}
/* (non-Javadoc)
* @see com.java.dao.AccountDAO#findUserByAccountId(int)
*/
public User findUserByAccountId(int accountId) {
// TODO Auto-generated method stub
return null;
}
/* (non-Javadoc)
* @see com.java.dao.AccountDAO#findAllAccount()
*/
public List findAllAccount() {
// TODO Auto-generated method stub
return null;
}
/* (non-Javadoc)
* @see com.java.dao.AccountDAO#batchDelAccount(int[])
*/
public boolean batchDelAccount(int[] accountId) throws Exception {
// TODO Auto-generated method stub
return false;
}
}
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发表时间：2007-03-06
DaoFactory
/*
* Created on Mar 6, 2007
*
* To change the template for this generated file go to
* Window>Preferences>Java>Code Generation>Code and Comments
*/
package com.java.dao;
import java.sql.Connection;
/**
* @author asdf
*
* To change the template for this generated type comment go to
* Window>Preferences>Java>Code Generation>Code and Comments
*/
public class DaoFactory
{
public static UserDAO getUserDAO(Connection connection)
{
return new UserDAOImpl(connection);
}
public static AccountDAO getAccountDAO(Connection connection)
{
return new AccountDAOImpl(connection);
}
}
UserService 类 /*
* Created on Mar 6, 2007
*
* To change the template for this generated file go to
* Window>Preferences>Java>Code Generation>Code and Comments
*/
package com.java.service;
import java.sql.Connection;
import java.sql.SQLException;
import java.util.List;
import com.java.db.Account;
import com.java.db.User;
import com.java.dao.AccountDAO;
import com.java.dao.DaoFactory;
import com.java.dao.UserDAO;
/**
* @author asdf
*
* To change the template for this generated type comment go to
* Window>Preferences>Java>Code Generation>Code and Comments
*/
public class UserService
{
private Connection connection;
private Connection getConnection()
{
//to-do open a connection form the dbPool
this.connection =null;
return connection;
}
public User findUser(int userId)
{
User user = null ;
try
{
getConnection();
UserDAO userDAO = DaoFactory.getUserDAO(this.connection);
user = userDAO.findUserById(userId);
}
catch(Exception e)
{
e.printStackTrace();
}
finally
{
try {
connection.close();
} catch (SQLException e1) {
// TODO Auto-generated catch block
e1.printStackTrace();
}
}
return user;
}
public void delUser(int userId)
{
try
{
getConnection();
connection.setAutoCommit(false);
AccountDAO accountDao = DaoFactory.getAccountDAO(this.connection);
UserDAO userDao =DaoFactory.getUserDAO(this.connection);
List list = userDao.findAccountByUserId(userId);
int[] accounts = new int[list.size()];
for(int i = 0;i<list.size();i++)
{
Account account =(Account)list.get(i);
accounts[i]= account.getAccountId();
}
accountDao.batchDelAccount(accounts);
userDao.delUser(userId);
connection.commit();
}
catch(Exception e)
{
e.printStackTrace();
try
{
connection.rollback();
} catch (SQLException e1)
{
// TODO Auto-generated catch block
e1.printStackTrace();
}
}
finally
{
try
{
connection.close();
} catch (SQLException e1) {
// TODO Auto-generated catch block
e1.printStackTrace();
}
}
}
}
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发表时间：2007-03-06
Client客户端调用程序
/*
* Created on Mar 6, 2007
*
* To change the template for this generated file go to
* Window>Preferences>Java>Code Generation>Code and Comments
*/
package com.java.client;
import com.java.service.UserService;
/**
* @author asdf
*
* To change the template for this generated type comment go to
* Window>Preferences>Java>Code Generation>Code and Comments
*/
public class Client
{
public static void main(String[] args)
{
//定义用户Id
int userId = 100;
UserService userService = new UserService();
userService.delUser(userId);
}
}
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