cglib动态代理之MethodProxy

        cglib动态代理的MethodProxy在优化方法调用的时候起了关键作用，下面是MethodProxy方法调用的实现，里面避免了使用反射调用。

1.目标类

package com.sf.contract.util.a17;public class Target {public void save(){System.out.println("save()");}public void save(int i){System.out.println("save(int)");}public void save(long j){System.out.println("save(long)");}
}

2.Proxy类

package com.sf.contract.util.a17;import org.springframework.cglib.proxy.MethodInterceptor;
import org.springframework.cglib.proxy.MethodProxy;import java.lang.reflect.Method;
import java.lang.reflect.UndeclaredThrowableException;public class Proxy extends Target{private MethodInterceptor interceptor;public void setInterceptor(MethodInterceptor interceptor){this.interceptor = interceptor;}static Method save0;static Method save1;static Method save2;static MethodProxy save0proxy;static MethodProxy save1proxy;static MethodProxy save2proxy;static {try {save0 = Target.class.getMethod("save");save1 = Target.class.getMethod("save", int.class);save2 = Target.class.getMethod("save", long.class);save0proxy = MethodProxy.create(Target.class, Proxy.class,"()V","save","saveSuper");save1proxy = MethodProxy.create(Target.class, Proxy.class,"(I)V","save","saveSuper");save2proxy = MethodProxy.create(Target.class, Proxy.class,"(J)V","save","saveSuper");} catch (NoSuchMethodException e) {throw new NoSuchMethodError(e.getMessage());}}//带原始功能的save方法public void saveSuper(){super.save();}public void saveSuper(int i){super.save(i);}public void saveSuper(long j){super.save(j);}//带增强功能的save方法@Overridepublic void save() {try {interceptor.intercept(this,save0,new Object[0],save0proxy);} catch (Throwable e) {throw new UndeclaredThrowableException(e);}}@Overridepublic void save(int i) {try {interceptor.intercept(this,save1,new Object[]{i},save1proxy);} catch (Throwable e) {throw new UndeclaredThrowableException(e);}}@Overridepublic void save(long j) {try {interceptor.intercept(this,save2,new Object[]{j},save2proxy);} catch (Throwable e) {throw new UndeclaredThrowableException(e);}}
}

        相比之前的实现，新增三个原始的方法（调用父类的方法）。并在里面创建MethodProxy对象，通过interceptor传入供回调使用，以save0为例。

save0proxy = MethodProxy.create(Target.class, Proxy.class,"()V","save0","saveSuper");

       需要使用到四个参数，第一个是目标类，第二个是代理类，第三个是描述，（）表示原始方法参数为空，V表示返回值为空，save是增强后的方法，saveSuper是原始的方法。

3.主类调用

package com.sf.contract.util.a17;import org.springframework.cglib.proxy.MethodInterceptor;
import org.springframework.cglib.proxy.MethodProxy;import java.lang.reflect.Method;public class a17 {public static void main(String[] args) {Proxy proxy = new Proxy();Target target = new Target();proxy.setInterceptor(new MethodInterceptor() {@Overridepublic Object intercept(Object p, Method method, Object[] objects, MethodProxy methodProxy) throws Throwable {System.out.println("before...");/*Object invoke = method.invoke(target, objects);//反射调用return invoke;*/return methodProxy.invokeSuper(p,objects);//内部无反射，结合代理调用}});proxy.save();proxy.save(1);proxy.save(2L);}
}

        1）使用methodProxy对象结合代理对象进行方法调用，里面没有用到反射。

         2)   使用methodProxy对象结合目标对象进行方法调用，里面也没有用到反射。

package com.sf.contract.util.a17;import org.springframework.cglib.proxy.MethodInterceptor;
import org.springframework.cglib.proxy.MethodProxy;import java.lang.reflect.Method;public class a17 {public static void main(String[] args) {Proxy proxy = new Proxy();Target target = new Target();proxy.setInterceptor(new MethodInterceptor() {@Overridepublic Object intercept(Object p, Method method, Object[] objects, MethodProxy methodProxy) throws Throwable {System.out.println("before...");/*Object invoke = method.invoke(target, objects);//反射调用return invoke;*//*return methodProxy.invokeSuper(p,objects);//内部无反射，结合代理调用*/return methodProxy.invoke(target,objects);//内部无反射，结合目标对象调用}});proxy.save();proxy.save(1);proxy.save(2L);}
}

输出结果：