通用工厂模式--学习笔记

通用工厂

导入依赖

<dependency>
    <groupId>junit</groupId>
    <artifactId>junit</artifactId>
    <version>4.13</version>
    <scope>test</scope>
</dependency>

工厂类

public class BeanFactory {
    private static Properties env = new Properties();

    static {
        try {
            InputStream inputStream = BeanFactory.class.getResourceAsStream("/applicationContext.properties");
            env.load(inputStream);
            inputStream.close();
        } catch (IOException e) {
            e.printStackTrace();
        }
    }
    
    public static Object getBean(String key){
        Object object = null;
        try {
            Class<?> clazz = Class.forName(env.getProperty(key));
            object = clazz.newInstance();
        } catch (Exception e) {
            e.printStackTrace();
        }

        return object;
    }
}

配置文件

在Resouce下建立applicationContext.properties文件

userService = top.xuankong.service.UserServiceImpl
userDao = top.xuankong.Dao.UserDaoImpl

测试

@Test
public void test(){
    UserDao userDao = (UserDao) BeanFactory.getBean("userDao");
    UserService userService = (UserService) BeanFactory.getBean("userService");
    System.out.println(userDao);
    System.out.println(userService);
}

输出结果：

top.xuankong.Dao.UserDaoImpl@4e515669 top.xuankong.service.UserServiceImpl@17d10166