jdk动态代理拦截方法

Love The Way You Lie 2022-07-15 07:29 163阅读 0赞

public interface Interceptor {
        
        /**
         * 前置操作
         */
        void before();
        
        /**
         * 后置操作
         */
        void after();
    }

/**
     * service方法拦截器
     */
    public class ServiceInterceptor implements Interceptor{
    
        @Override
        public void before() {
            System.out.println("service前置操作!");
        }
    
        @Override
        public void after() {
            System.out.println("service后置操作");
        }
        
    }

public class ServiceProxy implements InvocationHandler {
    
        private Interceptor interceptor = new ServiceInterceptor();
    
        private Object obj;
    
        public Object bind(Object obj) {
            this.obj = obj;
            return Proxy.newProxyInstance(
                    // 被代理类的ClassLoader
                    obj.getClass().getClassLoader(),
                    // 要被代理的接口,本方法返回对象会自动声称实现了这些接口
                    obj.getClass().getInterfaces(),
                    // 代理处理器对象
                    this);
        }
    
        @Override
        public Object invoke(Object proxy, Method method, Object[] args) throws Throwable {
            interceptor.before();
            obj = method.invoke(obj, args);
            interceptor.after();
            return obj;
        }
    
    }

/**
     * 业务方法
     */
    public interface TestService {
        
        public void insert();
    }

public class TestServiceImpl implements TestService{
    
        public void insert() {
            System.out.println("插入数据!");
        }
    }

public class Main {
        
        public static void main(String[] args) {
            TestService service = new TestServiceImpl();
            ServiceProxy proxy = new ServiceProxy();
            TestService service2 =  (TestService) proxy.bind(service);
            service2.insert();
        }
        
    }