Spring-IOC注册bean

比眉伴天荒 2022-03-25 03:35 232阅读 0赞

1.先新建一个没有被托管的类

public class UserController implements InitializingBean {
        @Autowired
        private UserService userService;
        public UserService getUserService() {
            return userService;
        }
        public void setUserService(UserService userService) {
            this.userService = userService;
        }
        @Override
        public void afterPropertiesSet() throws Exception {
            System.out.println("我是动态注册的你,不是容器启动的时候注册的你");
        }
        public String toAction(String content){
            return "-->" +  userService.doService(content);
        }
    }

2.接下来在定义一个Spring上下文的工具类

public class SpringContextUtil {
        private static ApplicationContext applicationContext;
        //获取上下文
        public static ApplicationContext getApplicationContext() {
            return applicationContext;
        }
        //设置上下文
        public static void setApplicationContext(ApplicationContext applicationContext) {
            SpringContextUtil.applicationContext = applicationContext;
        }
        //通过名字获取上下文中的bean
        public static Object getBean(String name) {
            return applicationContext.getBean(name);
        }
        //通过类型获取上下文中的bean
        public static Object getBean(Class<?> requiredType) {
            return applicationContext.getBean(requiredType);
        }
    }

3.在启动类中注入上下文

public class SpringbootServer4Application {
        public static void main(String[] args) {
            ApplicationContext app = SpringApplication.run(SpringbootServer4Application.class, args);
            SpringContextUtil.setApplicationContext(app);
        }
    }

4. 核心方法

public class UserControllerT extends SpringbootServer4ApplicationTests {
        @Autowired
        protected ApplicationContext ctx;
        @Test
        public void test() {
            //将applicationContext转换为ConfigurableApplicationContext
            ConfigurableApplicationContext configurableApplicationContext = (ConfigurableApplicationContext)ctx;
            // 获取bean工厂并转换为DefaultListableBeanFactory
            DefaultListableBeanFactory defaultListableBeanFactory = (DefaultListableBeanFactory) configurableApplicationContext.getBeanFactory();
            // 通过BeanDefinitionBuilder创建bean定义
            BeanDefinitionBuilder beanDefinitionBuilder = BeanDefinitionBuilder.genericBeanDefinition(UserController.class);
    //        // 设置属性userService,此属性引用已经定义的bean:userService,这里userService已经被spring容器管理了.
            beanDefinitionBuilder.addPropertyReference("userService", "userService");
            // 注册bean
            defaultListableBeanFactory.registerBeanDefinition("userController", beanDefinitionBuilder.getRawBeanDefinition());
            UserController userController = (UserController) ctx.getBean("userController");
            System.out.println(userController.toAction("动态注册生成调用"));
            //删除bean.
            //defaultListableBeanFactory.removeBeanDefinition("testService");
        }
    }