spring ApplicationContext版本的快速入门

代码示例：

public interface UserDao {
}
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public class UserDaoImpl implements UserDao {
}
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public interface UserService {
}
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public class UserServiceImpl implements UserService {
    private UserDao userDao;

    //该方法是Bean工厂去调用的，从工厂当中获得userDao设置到此处
    public void setUserDao(UserDao userDao) {
        this.userDao = userDao;
        System.out.println(userDao);
    }
}
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public class ApplicationContextTest {
    public static void main(String[] args) {
        ApplicationContext applicationContext = new ClassPathXmlApplicationContext("applicationContext.xml");
        UserService userService = (UserService) applicationContext.getBean("userService");
        System.out.println(userService);
    }
}