1.工厂方法模式定义了一个创建对象的接口，但由子类决定要实例化的类是哪一个，也就是说工厂方法模式让实例化推迟到子类
    2.mybatis中，事务模块和数据源模块都使用了工厂方法模式
    3.面对的目标一般都是单类的。

    1. /**
    2.  * 桌子接口
    3.  */
    4. public interface Desk {
    6.     String getType();
    7. }
    1. /**
    2.  * 木质桌子
    3.  */
    4. public class WoodenDesk implements Desk {
    6.     private String type = "木质桌子";
    8.     @Override
    9.     public String getType() {
    10.         return type;
    11.     }
    12. }
    1. /**
    2.  * 塑料桌子
    3.  */
    4. public class PlasticDesk implements Desk {
    6.     private String type = "塑料桌子";
    8.     @Override
    9.     public String getType() {
    10.         return type;
    11.     }
    12. }
    1. /**
    2.  * 工厂方法
    3.  */
    4. public interface DeskFactory {
    6.     Desk createDesk();
    8. }
    1. /**
    2.  *  木质桌子工厂
    3.  */
    4. public class WoodenDeskFactory implements DeskFactory {
    5.     @Override
    6.     public Desk createDesk() {
    7.         return new WoodenDesk();
    8.     }
    9. }
    1. /**
    2.  * 塑料桌子工厂
    3.  */
    4. public class PlasticDeskFactory implements DeskFactory {
    5.     @Override
    6.     public Desk createDesk() {
    7.         return new PlasticDesk();
    8.     }
    9. }
    1. /**
    2.  * 测试类
    3.  */
    4. public class Clienter {
    6.     public static void main(String[] args) {
    7.         DeskFactory deskFactory = new WoodenDeskFactory();
    8.         Desk desk = deskFactory.createDesk();
    9.     }
    10. }