Spring AOP用法(待完善)

Cglib实现AOP

    // 切所有方法
    @Test
    public void cglib1() {
        UserService target = new UserService();
        // 通过cglib实现AOP
        Enhancer enhancer = new Enhancer();
        enhancer.setSuperclass(UserService.class);
        // 定义额外逻辑，也就是代理逻辑
        // o:代理对象;     method:被代理类方法;  objects:方法参数;   methodProxy:代理类方法
        enhancer.setCallbacks(new Callback[]{(MethodInterceptor) (o, method, objects, methodProxy) -> {
            System.out.println("before...");
            Object result = methodProxy.invoke(target, objects);
            System.out.println("after...");
            return result;
        }});
        // 动态代理所创建出来的UserService代理对象
        UserService userService = (UserService) enhancer.create();
        // 执行这个userService的test方法时，就会额外会执行一些其他逻辑
        userService.test();
    }
 
    // 切指定方法
    @Test
    public void cglib2() {
        UserService target = new UserService();
        // 通过cglib实现AOP
        Enhancer enhancer = new Enhancer();
        enhancer.setSuperclass(UserService.class);
        // 定义多个代理逻辑, 数组类型
        enhancer.setCallbacks(new Callback[]{(MethodInterceptor) (o, method, objects, methodProxy) -> {
            System.out.println("before...");
            Object result = methodProxy.invoke(target, objects);
            System.out.println("after...");
            return result;
        }, NoOp.INSTANCE});
        // 设置切面匹配逻辑, return对应执行的callback数组
        enhancer.setCallbackFilter(method -> {
            if("test".equals(method.getName())) {
                return 0;
            }
            return 1;
        });
        // 动态代理所创建出来的UserService代理对象
        UserService userService = (UserService) enhancer.create();
        // 执行这个userService的test方法时，就会额外会执行一些其他逻辑
        userService.test();
        userService.print();
    }

下面执行结果, 可看出, 只有test执行了额外逻辑, print执行了空代理逻辑

before...
test---------
after...
print---------

JDK动态代理实现AOP

    @Test
    public void jdkProxy1() {
        UserService target = new UserService();
        Object proxy = Proxy.newProxyInstance(this.getClass().getClassLoader(), new Class[]{UserInterface.class}, (proxy1, method, args) -> {
            System.out.println("before...");
            Object result = method.invoke(target, args);
            System.out.println("after...");
            return result;
        });
        UserInterface userInterface = (UserInterface) proxy;
        userInterface.test();
    }

ProxyFactory实现AOP

spring对cglib和jdk动态代理进行了封装, 叫做ProxyFactory代理工厂, 会自动根据是否是接口, 去切换.如果实现了接口, 用jdk动态代理, 否则用cglib动态代理.

 
    // 代理类 - cglib动态代理
    @Test
    public void proxyFactory1() {
        UserService target = new UserService();
        ProxyFactory proxyFactory = new ProxyFactory();
        proxyFactory.setTarget(target);
        proxyFactory.addAdvice(new MethodInterceptor() {
            @Override
            public Object invoke(MethodInvocation invocation) throws Throwable {
                System.out.println("before...");
                Object proceed = invocation.proceed();
                System.out.println("after...");
                return proceed;
            }
        });
        UserService userService = (UserService) proxyFactory.getProxy();
        userService.test();
    }
 
    // 代理接口 - jdk动态代理
    @Test
    public void proxyFactory2() {
        UserService target = new UserService();
        ProxyFactory proxyFactory = new ProxyFactory();
        proxyFactory.setTarget(target);
        proxyFactory.addAdvice(new MethodInterceptor() {
            @Override
            public Object invoke(MethodInvocation invocation) throws Throwable {
                System.out.println("before...");
                Object proceed = invocation.proceed();
                System.out.println("after...");
                return proceed;
            }
        });
        UserInterface userService = (UserInterface) proxyFactory.getProxy();
        userService.test();
    }

Spring实现AOP

AOP概念

Aspect

Join point

Adivce

PointCut

Weaving