动态代理接口并注册到spring容器

梦里梦外; 2022-06-03 10:58 128阅读 0赞

### 1、目的 ###

实现将一个接口动态代理，并将该代理对象在spring容器初始化完成前注册到spring容器中。实现可以通过@Autowired等注释或其他方法从spring容器中获取该代理对象。

### 2、灵感来源 ###

翻mybatis的源代码获得，

### 3、代码 ###

[源代码下载][Link 1]

#### 3.1、接口类 ####

public interface TestService { 
    
        public String sayHello();
    }

#### 3.2、代理类 ####

public class MyProxy implements InvocationHandler{ 
    
        private Class<?> interfaceClass;
    
        public Object bind(Class<?> cls) {
            this.interfaceClass = cls;
            return Proxy.newProxyInstance(cls.getClassLoader(), new Class[] {interfaceClass}, this);
        }
    
        @Override
        public Object invoke(Object proxy, Method method, Object[] args) throws Throwable {
            return "hello world";
        }
    
    }

#### 3.3、代理工厂 ####

public class MyProxyFactory<T> implements FactoryBean<T> { 
    
        private Class<T> interfaceClass;
        public Class<T> getInterfaceClass() {
            return interfaceClass;
        }
        public void setInterfaceClass(Class<T> interfaceClass) {
            this.interfaceClass = interfaceClass;
        }
        @Override
        public T getObject() throws Exception {
            return (T) new MyProxy().bind(interfaceClass);
        }
    
        @Override
        public Class<?> getObjectType() {
            return interfaceClass;
        }
    
        @Override
        public boolean isSingleton() {
            // 单例模式
            return true;
        }
    
    }

#### 3.4、注册spring容器 ####

@Component
    public class MyRegistryBean implements ApplicationContextAware,BeanDefinitionRegistryPostProcessor{ 
    
        private ApplicationContext ctx;
        @Override
        public void postProcessBeanFactory(ConfigurableListableBeanFactory beanFactory) throws BeansException {
        }
        @Override
        public void postProcessBeanDefinitionRegistry(BeanDefinitionRegistry beanDefinitionRegistry) throws BeansException {
            // 需要被代理的接口
            Class<?> cls = TestService.class;
            BeanDefinitionBuilder builder = BeanDefinitionBuilder.genericBeanDefinition(cls);
            GenericBeanDefinition definition = (GenericBeanDefinition) builder.getRawBeanDefinition();
            definition.getPropertyValues().add("interfaceClass", definition.getBeanClassName());
            definition.setBeanClass(MyProxyFactory.class);
            definition.setAutowireMode(GenericBeanDefinition.AUTOWIRE_BY_TYPE);
            // 注册bean名,一般为类名首字母小写
            beanDefinitionRegistry.registerBeanDefinition("testService", definition);
        }
        @Override
        public void setApplicationContext(ApplicationContext ctx) throws BeansException {
            this.ctx = ctx;
        }
    
    }

#### 3.5、测试 ####

@RunWith(SpringJUnit4ClassRunner.class)  
    @ContextConfiguration({
       "classpath*:applicationContext.xml"})  
    public class Start { 
    
        @Autowired
        TestService testService;
    
        @Test
        public void test() {
            System.out.println(testService.sayHello());
        }
    }

控制台成功输出“hello world”，即成功在spring容器初始化完成前，将TestService接口代理，并将代理类注册到spring容器中。

[Link 1]: http://download.csdn.net/download/sz85850597/10174818