java动态代理--cglib

cglib的优点：

　　1. 性能高。CGLib底层采用ASM字节码生成框架，使用字节码技术生成代理类，比使用Java反射效率要高。

　　2. 无需实现接口。Java通过java.lang.reflect.Proxy和java.lang.reflect.InvocationHandler实现的动态代理必须实现接口，但现实中往往是没有接口的。

代码：

　　1. 随意定义一个类。　　

package pr.cgl.cglib;

/**
 * Created by LL on 2015/8/27.
 */
public class Tank {
   public void move(){
      System.out.println("Tank is moving...");
   }
   public void action(){
      System.out.println("Tank is start firing...");
   }
}
2. 实现　　

package pr.cgl.cglib;

import net.sf.cglib.proxy.Enhancer;
import net.sf.cglib.proxy.MethodInterceptor;
import net.sf.cglib.proxy.MethodProxy;
import java.lang.reflect.Method;
/**
 * Created by LL on 2015/8/27.
 */
public class CglibProxy implements MethodInterceptor {

   //要代理的原始对象
   private Object obj;

   public Object createProxy(Object target) {
      this.obj = target;
      Enhancer enhancer = new Enhancer();
      enhancer.setSuperclass(target.getClass());// 设置代理目标
      enhancer.setCallback(new CglibProxy());// 设置回调
      enhancer.setClassLoader(target.getClass().getClassLoader());
      return enhancer.create();
   }

   @Override
   public Object intercept(Object o, Method method, Object[] objects, MethodProxy methodProxy) throws Throwable {
      Long start = System.currentTimeMillis();
      System.out.println("start="+start);
      Object result = methodProxy.invokeSuper(o, objects);
      Long end = System.currentTimeMillis();
      System.out.println("end="+end);
      System.out.println("time spent :"+((end - start))+"   "+result);
      return result;
   }
}
3. 测试　

package pr.cgl.cglib;

/**
 * Created by LL on 2015/8/27.
 */
public class Test3 {
   public static void main(String[] args) {
      Tank tank = new Tank();
      CglibProxy proxy = new CglibProxy();
      Tank t = (Tank)proxy.createProxy(tank);
      t.action();
   }

}
输出：

　　start=1440662005592
　　Tank is start firing...
　　end=1440662005605
　　time spent :13 null