抽象工廠模式（Abstract Factory）：提供一個建立一系列相關或相互依賴物件的介面，而無需指定它們具體的類。

package abstractfactory;

/**
 * 抽象工廠方法(Abstract Factory)
 * 使用者實體類
 */
public class User {
    // ...
}

package abstractfactory;

/**
 * 抽象工廠方法(Abstract Factory)
 * 部門實體類
 */
public class Department {
    // ...
}

package abstractfactory;

/**
 * 抽象工廠方法(Abstract Factory)
 * 使用者介面
 */
public interface IUser {

    void insert(User user);

    User getUser(int id);

}
 

package abstractfactory;

/**
 * 抽象工廠方法(Abstract Factory)
 * SqlServerUser,用於訪問SQL Server的User
 */
public class SqlServerUser implements IUser {

    @Override
    public void insert(User user) {
        System.out.println("在SQL Server中給User表增加一條記錄");
    }

    @Override
    public User getUser(int id) {
        System.out.println("在SQL Server中根據ID得到User表中的一條記錄");
        return null;
    }

}
 

package abstractfactory;

/**
 * 抽象工廠方法(Abstract Factory)
 * AccessUser,用於訪問Access的User
 */
public class AccessUser implements IUser {

    @Override
    public void insert(User user) {
        System.out.println("在Access中給使用者表增加一條記錄");
    }

    @Override
    public User getUser(int id) {
        System.out.println("在Access中根據ID得到使用者表中的一條記錄");
        return null;
    }

}
 

package abstractfactory;

/**
 * 抽象工廠方法(Abstract Factory)
 * 部門介面
 */
public interface IDepartment {

    void insert(Department department);

    Department getDepartment(int id);

}

package abstractfactory;

/**
 * 抽象工廠方法(Abstract Factory)
 * SqlServerDepartment,用於訪問SQL Server的Department
 */
public class SqlServerDepartment implements IDepartment {

    @Override
    public void insert(Department department) {
        System.out.println("在SQL Server中給Department表增加一條記錄");
    }

    @Override
    public Department getDepartment(int id) {
        System.out.println("在SQL Server中根據ID得到Department表中的一條記錄");
        return null;
    }

}

package abstractfactory;

/**
 * 抽象工廠方法(Abstract Factory)
 * AccessDepartment,用於訪問Access的Department
 */
public class AccessDepartment implements IDepartment {

    @Override
    public void insert(Department department) {
        System.out.println("在Access中給部門表增加一條記錄");
    }

    @Override
    public Department getDepartment(int id) {
        System.out.println("在Access中根據ID得到部門表中的一條記錄");
        return null;
    }

}

package abstractfactory;

/**
 * 抽象工廠方法(Abstract Factory)
 * DataAccess,用簡單工廠模式實現
 */
public class DataAccess {

    private static final String DB = "SQLSERVER";
//    private static final String DB = "ACCESS";

    public static IUser createUser() {
        IUser result = null;
        switch (DB) {
            case "SQLSERVER":
                result = new SqlServerUser();
                break;
            case "ACCESS":
                result = new AccessUser();
                break;
        }
        return result;
    }

    public static IDepartment createDepartment() {
        IDepartment result = null;
        switch (DB) {
            case "SQLSERVER":
                result = new SqlServerDepartment();
                break;
            case "ACCESS":
                result = new AccessDepartment();
                break;
        }
        return result;
    }

}

package abstractfactory;

/**
 * 抽象工廠方法(Abstract Factory)
 * 客戶端main方法
 */
public class Client {

    public static void main(String[] args) {
        User user = new User();
        Department dept = new Department();

        IUser iUser = DataAccess.createUser();
        iUser.insert(user);
        iUser.getUser(1);

        IDepartment iDepartment = DataAccess.createDepartment();
        iDepartment.insert(dept);
        iDepartment.getDepartment(2);
    }

}