简单DAO层示例

在使用spring架构之前，我们怎么设计自己的DAO层的呢？

看下示例，比如我要保存User对象，那么运用工厂模式和单例模式来设计DAO层。

DAO层接口：

package com.lwf.dao;

public interface IBaseDao {

	void save(Object object);
}

 

DAO层接口实现，分MYSQL和ORACLE的实现

package com.lwf.dao;

public class BaseDao4MySql implements IBaseDao {

	public void save(Object object) {
		System.out.println("BaseDao4MySql");
	}

}

 

package com.lwf.dao;

public class BaseDao4Oracle implements IBaseDao {

	public void save(Object object) {
		System.out.println("BaseDao4Oracle");
	}

}

 

工厂类，利用工厂得到DAO

package com.lwf.dao;

public class BaseDaoFactory {

	private static BaseDaoFactory baseDaoFactory = new BaseDaoFactory();
	private String baseDaoName;
	private BaseDaoFactory(){
		 baseDaoName = "BaseDao4MySql";
		//加载xml属性
	}
	
	public static BaseDaoFactory getInstance(){
		return baseDaoFactory;
	}
	
	public IBaseDao getBaseDao(){
		IBaseDao iBaseDao = null;
		if(baseDaoName.equals("BaseDao4MySql")){
			iBaseDao = new BaseDao4MySql();
		}else if(baseDaoName.equals("BaseDao4Oracle")){
			iBaseDao = new BaseDao4Oracle();
		}
		return iBaseDao;
	}
}

 

 

具体的业务：用户管理类：

package com.lwf.manager;

import com.lwf.bean.User;
import com.lwf.dao.BaseDaoFactory;
import com.lwf.dao.IBaseDao;

public class UserManager {

	private static BaseDaoFactory factory = BaseDaoFactory.getInstance();
	private static IBaseDao baseDao = factory.getBaseDao();
	
	public static void save(User user){
		baseDao.save(user);
	}
}

 

用户类：model

package com.lwf.bean;

public class User {

	private String name;
	private int age;
	
	public String getName() {
		return name;
	}
	public void setName(String name) {
		this.name = name;
	}
	public int getAge() {
		return age;
	}
	public void setAge(int age) {
		this.age = age;
	}
	
}

 

下面是调用用户管理类的客户：

package com.lwf.client;

import com.lwf.bean.User;
import com.lwf.manager.UserManager;

public class Client {
	public static void main(String[] args) {
	
		User user = new User();
		user.setAge(11);
		user.setName("zhangshang");
		UserManager.save(user);
	}
}