java中的动态代理和CGLIB代理

JDK动态代理

1.先写一个自己的JDKProxy代理类，实现InvocationHandler

/**
 * JDK 动态代理类
 *
 * @author yeleichao
 * @date 2018-3-30.
 */
public class JDKProxy implements InvocationHandler {

    private Object target;//传入被代理类的引用

    public Object getInstance(Object target){
        this.target = target;

        Class<?> clazz = target.getClass();

        return Proxy.newProxyInstance(clazz.getClassLoader(),
                clazz.getInterfaces(),this);
    }


    @Override
    public Object invoke(Object proxy, Method method, Object[] args) throws Throwable {

        System.out.println("动态代理，进行业务操作");

        return method.invoke(target, args);
    }
}

2.写一个被代理的类

/**
 * 被代理类
 *
 * @author yeleichao
 * @date 2018-3-30.
 */
public class Yeleichao implements IYeleichao {

    @Override
    public void hello() {
        System.out.println("hello JAVA Proxy!");
    }
}

/**
 * 接口
 *
 * @author yeleichao
 * @date 2018-3-30.
 */
public interface IYeleichao {

    void hello();
}

3.测试类进行测试

/**
 * 测试jdk 动态代理
 *
 * @author yeleichao
 * @date 2018-3-30.
 */
public class TestJDKProxy {

    public static void main(String[] args) {
        Yeleichao yeleichao = new Yeleichao();
        IYeleichao iYeleichao = (IYeleichao) new JDKProxy().getInstance(yeleichao);
        iYeleichao.hello();

    }
}

4.结果展示

CGLIB代理

1.实现cglib代理前需要引入2个jar包

2.cglib代理类

/**
 * cglib 动态代理类
 *
 * @author yeleichao
 * @date 2018-3-30.
 */
public class CglibProxy implements MethodInterceptor {
    public Object getInstance(Class<?> clazz) throws Exception {
        Enhancer enhancer = new Enhancer(); //要把哪个设置为即将生成的新类父类 
        enhancer.setSuperclass(clazz);
        enhancer.setCallback(this);
        return enhancer.create();
    }

    @Override
    public Object intercept(Object o, Method method, Object[] objects, MethodProxy methodProxy) throws Throwable {
        System.out.println("cglib proxy，进行业务操作");
        return methodProxy.invokeSuper(o, objects);
    }
}

3.cglib测试类

/**
 * cglib 测试类
 *
 * @author yeleichao
 * @date 2018-3-30.
 */
public class CglibTest {
    public static void main(String[] args) throws Exception {
        Yeleichao yeleichao = (Yeleichao) new CglibProxy().getInstance(Yeleichao.class);
        yeleichao.hello();
    }
}

4.执行结果

结论：JDK动态代理需要实现接口，而CGLIB不需要实现接口