SpringBoot-动态代理反射注解四-动态代理对象注入到Spring容器

上一篇：SpringBoot 动态代理 | 反射 | 注解 |AOP 优化代码 (三)- 注解

本篇我们将实现通过代理生成的对象注入到 spring 容器中。
首先需要实现 BeanDefinitionRegistryPostProcessor, ApplicationContextAware 两个接口，作用分别为：
ApplicationContextAware：可以获得 ApplicationContext 对象，然后获取 Spring 容器中的对象
BeanDefinitionRegistryPostProcessor：可以将我们自定义的 bean 注入到 spring 容器

@Slf4j
@Component
public class HandlerBeanDefinitionRegistry implements BeanDefinitionRegistryPostProcessor, ApplicationContextAware {
    private ApplicationContext applicationContext;

    @Override
    public void postProcessBeanDefinitionRegistry(BeanDefinitionRegistry beanDefinitionRegistry) throws BeansException {
        /**
         * 获取 AutoImpl 注解的接口，这些接口就需要通过动态代理提供默认实现
         */
        Set<Class<?>> classes = getAutoImplClasses();
        for (Class<?> clazz : classes) {
            /**
             * 获取继承自 HandlerRouter 的接口的泛型的类型 typeName，传入到 DynamicProxyBeanFactory
             * 以便传入到 DynamicProxyBeanFactory 扫描 typeName 的实现类，然后按照 feign 和 url 两种实现
             * 方式分类
             */

            Type[] types = clazz.getGenericInterfaces();
            ParameterizedType type = (ParameterizedType) types[0];
            String typeName = type.getActualTypeArguments()[0].getTypeName();

            /**
             * 通过 FactoryBean 注入到 spring 容器，HandlerInterfaceFactoryBean 实现以下功能：* 1. 调用动态代理 DynamicProxyBeanFactory 提供 HandlerRouter 子接口的默认实现
             * 2. 将第一步的默认实现，注入到 spring 容器
             */

            HandlerRouterAutoImpl handlerRouterAutoImpl = clazz.getAnnotation(HandlerRouterAutoImpl.class);
            BeanDefinitionBuilder builder = BeanDefinitionBuilder.genericBeanDefinition(clazz);
            GenericBeanDefinition definition = (GenericBeanDefinition) builder.getRawBeanDefinition();
            definition.getPropertyValues().add("interfaceClass", clazz);
            definition.getPropertyValues().add("typeName", typeName);
            definition.getPropertyValues().add("context", applicationContext);
            definition.setBeanClass(HandlerInterfaceFactoryBean.class);
            definition.setAutowireMode(GenericBeanDefinition.AUTOWIRE_BY_TYPE);
            beanDefinitionRegistry.registerBeanDefinition(handlerRouterAutoImpl.name(), definition);
        }
    }

    @Override
    public void postProcessBeanFactory(ConfigurableListableBeanFactory configurableListableBeanFactory) throws BeansException {log.info("------------------------>postProcessBeanFactory");
    }

    /**
     * 通过反射扫描出所有使用 HandlerRouterAutoImpl 的类
     * @return
     */
    private Set<Class<?>> getAutoImplClasses() {
        Reflections reflections = new Reflections(
                "io.ubt.iot.devicemanager.impl.handler.*",
                new TypeAnnotationsScanner(),
                new SubTypesScanner());
        return reflections.getTypesAnnotatedWith(HandlerRouterAutoImpl.class);
    }

    @Override
    public void setApplicationContext(ApplicationContext applicationContext) throws BeansException {
        this.applicationContext = applicationContext;
        log.info("------------------->setApplicationContext");
    }

    /**
     * 通过 class 获取所有该类型的 bean
     *
     * @param clazz
     * @return
     */
    private Map<String, T> getBeans(Class<T> clazz) {return applicationContext.getBeansOfType(clazz);
    }

    private String getYmlProperty(String propery) {return applicationContext.getEnvironment().getProperty(propery);
    }
}

HandlerInterfaceFactoryBean 通过动态代理创建默认实现类

@Slf4j
@Data
public class HandlerInterfaceFactoryBean<T> implements FactoryBean<T> {
    private Class<T> interfaceClass;
    private String typeName;
    private ApplicationContext context;
    @Override
    public T getObject() throws Exception {Object object = DynamicProxyBeanFactory.newMapperProxy(typeName, context, interfaceClass);
        return (T) object;
    }

    @Override
    public Class<?> getObjectType() {return interfaceClass;}

    @Override
    public boolean isSingleton() {return true;}
}

DynamicProxyBeanFactory 最终实现

@Slf4j
public class DynamicProxyBeanFactory implements InvocationHandler {

    private String className;
    private ApplicationContext applicationContext;

    private Map<ClientType, Object> clientMap = new HashMap<>(2);

    public DynamicProxyBeanFactory(String className, ApplicationContext applicationContext) {
        this.className = className;
        this.applicationContext = applicationContext;
    }

    @Override
    public Object invoke(Object proxy, Method method, Object[] args) throws Throwable {if (clientMap.size() == 0) {initClientMap();
        }
       
        Integer env = (Integer) args[0];
        return 1 == env.intValue() ? clientMap.get(ClientType.FEIGN) : clientMap.get(ClientType.URL);
    }

    private void initClientMap() throws ClassNotFoundException {
        // 获取 classStr 接口的所有实现类
        Map<String,?> classMap = applicationContext.getBeansOfType(Class.forName(className));
        log.info("DynamicProxyBeanFactory className:{} impl class:{}",className,classMap);

        for (Map.Entry<String,?> entry : classMap.entrySet()) {
            // 根据 ApiClientType 注解将实现类分为 Feign 和 Url 两种类型
            ApiClient apiClient = entry.getValue().getClass().getAnnotation(ApiClient.class);
            if (apiClient == null) {continue;}
            clientMap.put(apiClient.type(), entry.getValue());
        }
        log.info("DynamicProxyBeanFactory clientMap:{}",clientMap);
    }


    public static <T> T newMapperProxy(String classStr,ApplicationContext applicationContext,Class<T> mapperInterface) {ClassLoader classLoader = mapperInterface.getClassLoader();
        Class<?>[] interfaces = new Class[]{mapperInterface};
        DynamicProxyBeanFactory proxy = new DynamicProxyBeanFactory(classStr,applicationContext);
        return (T) Proxy.newProxyInstance(classLoader, interfaces, proxy);
    }
}

以上便是注解获取目标类，动态代理提供默认实现，并注入到 Spring 容器的核心代码。

单元测试

@Slf4j
@SpringBootTest
@RunWith(SpringRunner.class)
public class OptimizationTest {

    @Autowired
    @Qualifier("deviceHandlerRouter")
    private DeviceHandlerRouter deviceHandlerRouter;

    @Test
    public void dispatchApp() {DeviceHandler deviceHandlerFeignImpl = deviceHandlerRouter.getHandler(1, null);
        log.info("DeviceHandler-------------->{}",deviceHandlerFeignImpl);

        DeviceHandler deviceHandlerUrlImpl = deviceHandlerRouter.getHandler(2, null);
        log.info("DeviceHandler-------------->{}",deviceHandlerUrlImpl);
    }

   
}

Aop 优化代码待续

参考文章 https://blog.csdn.net/qq_2059…