《大话设计模式》第十五章

package ch15;

public class User {
	private int id;
	
	private String name;

	public User(String name) {
		this.name = name;
	}

	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;
	}
}

 

package ch15;

public interface IUser {
	void insert(User user);
	User getUser(int id);
}

 

package ch15;

public class AccessUser implements IUser {

	public void insert(User user) {
		System.out.println("在Access里插入" + user.getName());
	}

	public User getUser(int id) {
		System.out.println("在Access里根据ID得到User");
		return null;
	}

}

 

package ch15;

public class SqlserverUser implements IUser {
	public void insert(User user) {
		System.out.println("在SQL Server里插入" + user.getName());
	}
	
	public User getUser(int id) {
		System.out.println("在SQL Server里根据ID得到User");
		return null;
	}
}

 

package ch15;

public interface IFactory {
	IUser createUser();
}

 

package ch15;

public class AccessFactory implements IFactory {

	public IUser createUser() {
		return new AccessUser();
	}

}

 

package ch15;

public class SqlserverFactory implements IFactory {

	public IUser createUser() {
		return new SqlserverUser();
	}

}

 

package ch15;

/**
 * 抽象工厂模式
 * @author Administrator
 *
 */
public class Client {

	/**
	 * @param args
	 */
	public static void main(String[] args) {
		User user = new User("X");
		IFactory factory = new SqlserverFactory();
		IUser iu = factory.createUser();
		iu.insert(user);
		iu.getUser(0);
	}

}

抽象工厂模式和工厂方法模式很像,那么有什么区别吗?

工厂方法,返回一个具体的类型,比如Integer.valueOf,返回的是Integer的实例,而且Integer不是抽象类,是可以实例化的;

抽象工厂方法,返回的可能是任何的类型,Calendar.getInstance,返回的可能是BuddhistCalendar,也可能是JapaneseImperialCalendar,也可能是GregorianCalendar,而且Calendar是抽象类,不能实例化。