设计模式——简单工厂

例子一：

package simpleFactory;

public abstract class Operation {
	protected double NumberA;
	protected double NumberB;
	public double getNumberA()
	{
		return NumberA;
	}
	public double getNumberB()
	{
		return NumberB;
	}
	public void setNumberA(double n)
	{
		NumberA = n;
	}
	public void setNumberB(double n)
	{
		NumberB = n;
	}
	public abstract double getResult();
}

package simpleFactory;

public class Add extends Operation{

	@Override
	public double getResult() {
		return NumberA + NumberB;
	}

}

package simpleFactory;

public class Minus extends Operation{

	@Override
	public double getResult() {
		return NumberA - NumberB;
	}

}

package simpleFactory;

public class SimpleFactory {
	public static Operation createOperation(char o)
	{
		switch(o)
		{
		case '+':
			return new Add();
		case '-':
			return new Minus();
		default:
			return null;
		}

	}
}

package simpleFactory;

public class Client {
	public static void main(String[] args) {
		Operation add = SimpleFactory.createOperation('+');
		add.setNumberA(1);
		add.setNumberB(1);
		System.out.println(add.getResult());
		Operation minus = SimpleFactory.createOperation('-');
		minus.setNumberA(2);
		minus.setNumberB(3);
		System.out.println(minus.getResult());
	}
}

例子二：

package simpleFactory2;

public interface IUser {
	public void insert(String s);
	public String get(int id);
}

package simpleFactory2;

public class AccessUser implements IUser{

	@Override
	public String get(int id) {
		System.out.println("AccessUser select from xx where ID = " + id);
		return null;
	}

	@Override
	public void insert(String s) {
		System.out.println("insert into xx value " + s);
	}

}

package simpleFactory2;

public class sqlserverUser implements IUser{

	@Override
	public String get(int id) {
		System.out.println("sqlserver select from xx where ID = " + id);
		return null;
	}

	@Override
	public void insert(String s) {
		System.out.println("sqlserver insert into xx value " + s);
	}
	
}

package simpleFactory2;

public interface IFactory {
	public IUser createuser();
}

package simpleFactory2;

public class AccessFactory implements IFactory{

	@Override
	public IUser createuser() {
		return new AccessUser();
	}
	
}

package simpleFactory2;

public class sqlserverFactory implements IFactory{

	@Override
	public IUser createuser() {
		return new sqlserverUser();
	}
	
}

package simpleFactory2;

public class Client {
	public static void main(String[] args) {
//		IFactory factory = new sqlserverFactory();
	    IFactory factory = new AccessFactory();
		IUser user =  factory.createuser();
		user.insert("test");
		user.get(1);
	}
}