java动态代理vs静态代理

静态代理：编译期就能确定代理类的类型，动态代理：运行期间"动态"确定代理类的类型，代理类和被代理类需要实现相同的接口

静态代理举例：

/**
 * @Auther: zxt
 * @Date: 2019/12/24 14:58
 * @Description:
 */
interface Sign{
    void sign();
}
class LiuDeHua implements Sign{

    @Override
    public void sign() {
        System.out.println("liu de hua sign");
    }
}
class JingjiRen implements Sign{
    private Sign liuDeHua;

    public JingjiRen(Sign liuDeHua) {
        this.liuDeHua = liuDeHua;
    }

    @Override
    public void sign() {
        System.out.println("===准备场地====");
        liuDeHua.sign();
        System.out.println("===安排下一场地==");
    }
}


public class StaticFactoryTest {
    public static void main(String[] args) {
       Sign sign = new LiuDeHua();
       Sign proxySign = new JingjiRen(sign);
       proxySign.sign();
    }
}

执行结果:

===准备场地====
liu de hua sign
===安排下一场地==

 

 

动态代理举例：

/**
 * @Auther: zxt
 * @Date: 2019/12/24 15:05
 * @Description: 动态代理
 */
class DynamicFacotry{

    private Object object;//真实的被代理类
    private InvocationHandler handler;
    public DynamicFacotry(Object object, InvocationHandler handler) {
        this.object = object;
        this.handler = handler;
    }

    public static Object getInstance(Object object, InvocationHandler handler){
        return Proxy.newProxyInstance(object.getClass().getClassLoader(),object.getClass().getInterfaces(),handler);
    }
}
public class DynamicFactoryTest {
    public static void main(String[] args) {
        final Sign sign = new LiuDeHua();
        Sign proxy = (Sign) DynamicFacotry.getInstance(sign, new InvocationHandler() {
            @Override
            public Object invoke(Object proxy, Method method, Object[] args) throws Throwable {
                System.out.println("===动态代理start======");
                Object obj = method.invoke(sign);
                System.out.println("====动态代理end==========");
                return obj;
            }
        });
        proxy.sign();
    }
}

执行结果：

===动态代理start======
liu de hua sign
====动态代理end==========