大话设计模式笔记 抽象工厂模式

 

抽象工厂模式（Abstract Factory），提供一个创建一系列相关或相互依赖对象的接口，而无需指定他们具体的类。

 

 

 

所有在用简单工厂的地方，都可以考虑用反射技术，搭配配置文件去除switch 或 if，解除分支判断带来的耦合。

（C#）Assembly.load("程序集名称").CreateInstance(""命名空间.类名称)。

 

 

package abstractFactor;

public class User {
    private String id;

    public String getId() {
        return id;
    }

    public void setId(String id) {
        this.id = id;
    }
}

 

package abstractFactor;

public class Department {

    private String id;

    public String getId() {
        return id;
    }

    public void setId(String id) {
        this.id = id;
    }
    
}

 

package abstractFactor;

public interface ITest<T> {

    void Insert(T object);
    
    T getObject(String id);
}

 

package abstractFactor;

public class SqlserverUser implements ITest<User> {

    @Override
    public void Insert(User object) {
        System.out.println("SqlserverUser Insert");
    }

    @Override
    public User getObject(String id) {
        System.out.println("SqlserverUser getObject");
        return null;
    }

}

 

package abstractFactor;

public class OracleUser implements ITest<User> {

    @Override
    public void Insert(User object) {
        System.out.println("OracleUser Insert");
    }

    @Override
    public User getObject(String id) {
        System.out.println("OracleUser getObject");
        return null;
    }

}

 

package abstractFactor;

import java.lang.reflect.Constructor;
import java.lang.reflect.InvocationTargetException;

public class DataAccess {

    private static String db = "Sqlserver";

    public static ITest<User> createUser() {
        String className = "abstractFactor."+db + "User";
        System.out.println(className);
        Class<ITest<User>> clazz;
        Constructor<ITest<User>> constructor = null;
        try {
            // 获得类对象
            clazz = (Class<ITest<User>>) Class.forName(className);
            // 获得构造器
            constructor = clazz.getConstructor(null);

        } catch (ClassNotFoundException e) {
            // TODO Auto-generated catch block
            e.printStackTrace();
        } catch (NoSuchMethodException e) {
            // TODO Auto-generated catch block
            e.printStackTrace();
        } catch (SecurityException e) {
            // TODO Auto-generated catch block
            e.printStackTrace();
        } catch (IllegalArgumentException e) {
            // TODO Auto-generated catch block
            e.printStackTrace();
        } finally {
            try {
                // 创建对象
                return (ITest<User>) constructor.newInstance();
            } catch (InstantiationException | IllegalAccessException
                    | IllegalArgumentException | InvocationTargetException e) {
                // TODO Auto-generated catch block
                e.printStackTrace();
            }
        }
        return null;
    }
    public static void main(String[] args) {
        User user=new User();
        ITest<User> iu=DataAccess.createUser();
        iu.Insert(user);
        iu.getObject("1");
    }
}