Spring工厂的过程

不使用new 进行创建实例对象

public class BeanFactory {
   private static   ResourceBundle bundle;

    static {
//        加载配置文件
      bundle = ResourceBundle.getBundle("applicationContext");
        String userService = bundle.getString("userService");
        System.out.println("userService = " + userService);

    }



    public static UserService getUserServiceImpl() {
        UserService userService = null;
        try {
            Class clazz = Class.forName(bundle.getString("userService"));
            userService = (UserService) clazz.newInstance();
        } catch (Exception e) {
            e.printStackTrace();
        }
        return userService;
    }

    public static UserMapper getUserMapperImpl() {
        UserMapper userMapper = null;
        try {
            Class clazz = Class.forName(bundle.getString("userMapper"));
            userMapper = (UserMapper) clazz.newInstance();
        } catch (Exception e) {
            e.printStackTrace();
        }
        return userMapper;
    }
}

通过使用泛型对工厂进一步优化

public class NewBeanFactory {
    private static ResourceBundle bundle;

    static {
//        加载配置文件
        bundle = ResourceBundle.getBundle("applicationContext");
        String userService = bundle.getString("userService");
        System.out.println("userService = " + userService);

    }



    public static Object getBean(String key) {
        Object object = null;
        try {
            Class clazz = Class.forName(bundle.getString(key));
            object = clazz.newInstance();
        } catch (Exception e) {
            e.printStackTrace();
        }
        return object;
    }
//    泛型
    public static  T getBean(String key,Class tClass) {
        Object object = null;
        T cast=null;
        try {
            Class clazz = Class.forName(bundle.getString(key));
            object = clazz.newInstance();
             cast = tClass.cast(object);
        } catch (Exception e) {
            e.printStackTrace();
        }
        return cast;
    }
}

使用Spring管理

1.引入依赖

  

    
      org.springframework
      spring-context
      5.3.20
    

2.创建配置文件applicationContext