代理:即为访问对象添加一层控制层,使其间接化,控制层可以为对象访问添加操作属性。
实例:
import java.lang.reflect.Method;
import net.sf.cglib.proxy.Enhancer;
import net.sf.cglib.proxy.MethodInterceptor;
import net.sf.cglib.proxy.MethodProxy;
public class MyMethodInterceptor implements MethodInterceptor {
public String myFun(String arg){
return "hello," + arg ;
}
public Object intercept(Object obj, Method method, Object[] args, MethodProxy proxy) throws Throwable {
String methodName = method.getName();
System. out .println( "[intercept] fun invoked before" );
String result = (String)args[0] + "..." ;
System. out .println( result );
System. out .println( "[intercept] fun invoked after" );
return result;
}
public Object createProxy(){
Enhancer enhancer = new Enhancer();
enhancer.setSuperclass(MyMethodInterceptor. class );
enhancer.setCallback( this );
return enhancer.create();
}
public static void main(String[] args) {
MyMethodInterceptor ss = new MyMethodInterceptor();
MyMethodInterceptor proxy = (MyMethodInterceptor)ss.createProxy();
c1.myFun( "cglib test" );
}
}
通用工具类:
package org.windwant.spring.core.proxy;
import org.springframework.cglib.proxy.Enhancer;
import org.springframework.cglib.proxy.MethodInterceptor;
import org.springframework.cglib.proxy.MethodProxy;
import java.lang.reflect.Method;
/**
* Created by windwant on 2016/6/4.
*/
public class MyCGLIBProxy implements MethodInterceptor {
private Enhancer enhancer = new Enhancer();
public Object getProxy(Class clazz){
enhancer.setSuperclass(clazz);
enhancer.setCallback(this);
return enhancer.create();
}
public Object intercept(Object o, Method method, Object[] objects, MethodProxy methodProxy) throws Throwable {
System.out.println("cglib before action");
Object result = methodProxy.invokeSuper(o, objects);
System.out.println("cglib after action");
return result;
}
}
MyCGLIBProxy p = new MyCGLIBProxy();
Performer pp = (Performer) p.getProxy(XXXX.class);
pp.XXXX();
package org.windwant.spring.core.proxy;
import java.lang.reflect.InvocationHandler;
import java.lang.reflect.Method;
import java.lang.reflect.Proxy;
/**
* Created by windwant on 2016/6/4.
*/
public class MyJDKProxy implements InvocationHandler{
private Object targetObject;
public Object getInstance(Object targetObject){
this.targetObject = targetObject;
return Proxy.newProxyInstance(targetObject.getClass().getClassLoader(), targetObject.getClass().getInterfaces(), this);
}
public Object invoke(Object proxy, Method method, Object[] args) throws Throwable {
System.out.println("proxy: before action");
Object resutl = method.invoke(targetObject, args);
System.out.println("proxy: after action");
return resutl;
}
}
MyJDKProxy mp = new MyJDKProxy();
XXX ap = (XXX) mp.getInstance(new APerformer());
ap.XX();
package org.windwant.spring.core.proxy;
import javassist.ClassPool;
import javassist.CtClass;
import javassist.CtMethod;
/**
* Created by windwant on 2016/9/18.
*/
public class MyJavassistProxy {
public Object getProxySelf(String clazz, String pClazz, String methodName, String methodBefore, String methodAfter){
ClassPool cp = ClassPool.getDefault();
CtClass ct;
try {
ct = cp.get(clazz);
if(pClazz != null){
ct.setSuperclass(cp.get(pClazz));
}
ct.writeFile();
ct.defrost();
CtMethod m = ct.getDeclaredMethod(methodName);
if(methodBefore != null) {
m.insertBefore(methodBefore);
}
if(methodAfter != null) {
m.insertAfter(methodAfter);
}
Class c = ct.toClass();
return c.newInstance();
} catch (Exception e) {
e.printStackTrace();
}
return null;
}
}
public void testJavassist(){
String clazz = "org.windwant.spring.core.proxy.Hello";
String methodBefore = "{ System.out.println(\"method before...:\"); }";
String methodAfter = "{ System.out.println(\"method after...:\"); }";
String pClazz = "org.windwant.spring.core.proxy.HelloP";
Hello hello = (Hello) new MyJavassistProxy().getProxySelf(clazz, null, "say",
methodBefore, methodAfter);
hello.say();
}