cglib是個好東東,說牛刀,是因為它很強大,用途很廣。小試,是因為僅僅用它做了個類似hello world的小程序。
cglib是Spring、Hibernate依賴的核心包,但是cglib還算不上最底層的,因為它是在asm包之上做了封裝,以增強易用性。據了解,Hibernate3.2已經不再依賴cglib了,而直接依賴asm。這些都不影響cglib的強大功能。
很希望將spring、JDK、cglib的動態代理三者放到一起做個比較(實際上,spring、jdk的代理已經比較過了),也許是地震原因,心情一直沒有平靜下來,無心去寫。下面就先給個地震前例子看看,因為很簡單,所以就不細說了,有空了再做深入研究。
其實所有代理道理都是一樣,就是通過代理對象去調用目標對象,并且在代理對象中做點“手腳”--加入一些其他操作。
下面看例子:
目標對象
/**
* Created by IntelliJ IDEA.<br>
* <b>User</b>: leizhimin<br>
* <b>Date</b>: 2008-5-14 0:38:35<br>
* <b>Note</b>: Please add comment here!
*/
public class Target {
public String execute() {
String message = "----------test()----------";
System.out.println(message);
return message;
}
}
攔截器
import net.sf.cglib.proxy.MethodInterceptor;
import net.sf.cglib.proxy.MethodProxy;
import java.lang.reflect.Method;
/**
* Created by IntelliJ IDEA.<br>
* <b>User</b>: leizhimin<br>
* <b>Date</b>: 2008-5-14 0:39:08<br>
* <b>Note</b>: Please add comment here!
*/
public class MyMethodInterceptor implements MethodInterceptor {
public Object intercept(Object object, Method method, Object[] args, MethodProxy methodProxy) throws Throwable {
System.out.println(">>>MethodInterceptor start...");
Object result = methodProxy.invokeSuper(object,args);
System.out.println(">>>MethodInterceptor ending...");
return "hahahh";
}
}
import net.sf.cglib.proxy.Enhancer;
/**
* Created by IntelliJ IDEA.<br>
* <b>User</b>: leizhimin<br>
* <b>Date</b>: 2008-5-14 0:41:01<br>
* <b>Note</b>: Please add comment here!
*/
public class TestCglibProxy {
public static void main(String rags[]){
Target target = new Target();
TestCglibProxy test = new TestCglibProxy();
Target proxyTarget = (Target)test.createProxy(Target.class);
String res=proxyTarget.execute();
System.out.println(res);
}
public Object createProxy(Class targetClass){
Enhancer enhancer = new Enhancer();
enhancer.setSuperclass(targetClass);
enhancer.setCallback(new MyMethodInterceptor());
return enhancer.create();
}
}
運行結果:
C:\classes>java -cp .;C:\classes\cglib-nodep-2.1_3.jar TestCglibProxy
>>>MethodInterceptor start...
----------test()----------
>>>MethodInterceptor ending...
hahahh
C:\classes>