bean实例化-静态工厂

• 静态工厂

  //OrderDaoFactory.java 工厂类
  public class OrderDaoFactory {
      public static OrderDao getOrderDao(){
          System.out.println("factory setup...");
          return new OrderDaoImpl();
      }
  }
  
  //OrderDao.java 接口类
  public interface OrderDao {
      void save();
  }
  
  //OrderDaoImpl.java 接口实现类
  public class OrderDaoImpl implements OrderDao {
      @Override
      public void save() {
          System.out.println("order dao save...");
      }
  }
  
  //AppForInstanceOrder.java 测试类
  public class AppForInstanceOrder {
  public static void main(String[] args) {
      //通过静态工厂创建对象
      /*OrderDao orderDao = OrderDaoFactory.getOrderDao();
      orderDao.save();*/
  
      ApplicationContext ctx = new ClassPathXmlApplicationContext("applicationContext.xml");
  
      OrderDao orderDao = (OrderDao) ctx.getBean("orderDao");
  
      orderDao.save();
      }
  }
  

• 配置

  <!--方式二：使用静态工厂实例化bean-->
  <bean id="orderDao" class="com.charley.factory.OrderDaoFactory" factory-method="getOrderDao"/>