一般而言，动态代理分为两种，一种是JDK反射机制提供的代理，另一种是CGLIB代理。在JDK代理，必须提供接口，而CGLIB则不需要提供接口，在Mybatis里两种动态代理技术都已经使用了，在Mybatis中通常在延迟加载的时候才会用到CGLIB动态代理。

1.JDK动态代理：

public interface Rent {    public void rent();}

public class Landlord implements Rent{    @Override    public void rent() {        System.out.println("房东要出租房子了！");    }}

import java.lang.reflect.InvocationHandler;import java.lang.reflect.Method;public class Intermediary implements InvocationHandler{        private Object post;        Intermediary(Object post){        this.post = post;    }    @Override    public Object invoke(Object proxy, Method method, Object[] args)            throws Throwable {        Object invoke = method.invoke(post, args);        System.out.println("中介：该房源已发布！");        return invoke;    }}

import java.lang.reflect.Proxy;public class Test {    public static void main(String[] args) {        Rent rent = new Landlord();        Intermediary intermediary = new Intermediary(rent);        Rent rentProxy = (Rent) Proxy.newProxyInstance(rent.getClass().getClassLoader(), rent.getClass().getInterfaces(), intermediary);        rentProxy.rent();    }}

2.CGLIB动态代理：

public class Landlord {    public void rent(){        System.out.println("房东要出租房子了！");    }}

import java.lang.reflect.Method;import net.sf.cglib.proxy.MethodInterceptor;import net.sf.cglib.proxy.MethodProxy;public class Intermediary implements MethodInterceptor {    @Override    public Object intercept(Object object, Method method, Object[] args,MethodProxy methodProxy) throws Throwable {        Object intercept = methodProxy.invokeSuper(object, args);        System.out.println("中介：该房源已发布！");        return intercept;    }}

import net.sf.cglib.proxy.Enhancer;public class Test {    public static void main(String[] args) {        Intermediary intermediary = new Intermediary();                Enhancer enhancer = new Enhancer();          enhancer.setSuperclass(Landlord.class);        enhancer.setCallback(intermediary);                Landlord rentProxy = (Landlord) enhancer.create();        rentProxy.rent();    }}