Java动态代理的示例详解

public interface IPhone {

    
    void sellPhone();
}

public class TargetPhone implements IPhone {
    @Override
    public void sellPhone() {
        System.out.println("苹果公司正在出售手机");
    }
}

public class ProxyPhone {

    private Object target;

    public ProxyPhone(Object target){
        this.target = target;
    }

    public Object getProxyInstance() {
        return Proxy.newProxyInstance(target.getClass().getClassLoader(),
                target.getClass().getInterfaces(),
                new InvocationHandler() {
                    @Override
                    public Object invoke(Object proxy, Method method, Object[] args) throws Throwable {
                        System.out.println("JDK动态代理开始之前，添加业务逻辑XXX");
                        //使用反射机制来调用目标对象的方法:解决了问题二
                        Object invoke = method.invoke(target, args);
                        System.out.println("JDK动态代理结束之后，添加业务逻辑XXX");
                        return invoke;
                    }
                });
    }
}

public class Test {
    public static void main(String[] args) {
        // 创建目标类
        TargetPhone targetPhone = new TargetPhone();
        // 创建代理类
        IPhone iPhone = (IPhone) new ProxyPhone(targetPhone).getProxyInstance();
        System.out.println(iPhone.getClass());
        // 通过代理类调用目标方法
        iPhone.sellPhone();
    }
}

public class TargetPhone {

    public void sellPhone() {
        System.out.println("苹果公司正在出售手机");
    }
}

public class ProxyFactory implements MethodInterceptor {

    private Object target;

    public ProxyFactory(Object target){
        this.target = target;
    }

    public Object getProxyInstance(){
        // 创建一个工具类
        Enhancer enhancer = new Enhancer();
        // 设置父类
        enhancer.setSuperclass(target.getClass());
        // 设置回调函数
        enhancer.setCallback(this);
        // 创建子类对象，即代理对象
        return enhancer.create();
    }

    @Override
    public Object intercept(Object o, Method method, Object[] objects, MethodProxy methodProxy) throws Throwable {
        System.out.println("cglib动态代理开始之前，添加业务逻辑xxxx");
        Object invoke = method.invoke(target, objects);
        System.out.println("cglib动态代理之后，添加业务逻辑");
        return invoke;
    }
}

public class Test {
    public static void main(String[] args) {
        // 创建目标对象
        TargetPhone targetPhone = new TargetPhone();
        // 获取代理对象
        TargetPhone proxyInstance = (TargetPhone)new ProxyFactory(targetPhone).getProxyInstance();
        // 通过代理对象调用具体的方法
        proxyInstance.sellPhone();
    }
}