关于动态代理的问题，求详解 - 黑马程序员技术交流社区

package com.itheima.day03.aopframework;
import java.io.IOException;
import java.io.InputStream;
import java.util.Properties;
import com.itheima.day03.Advice;
public class BeanFactory {
Properties prop = new Properties();
public BeanFactory(InputStream is) {
try {
prop.load(is);
} catch (IOException e) {
e.printStackTrace();
}
}
public Object getBean(String name) {
// 获取类名
String className = prop.getProperty(name);
// System.out.println(className);
Object bean = null;
try {
// 获取类字节码文件
Class clazz = Class.forName(className);
// 创建实例
bean = clazz.newInstance();
} catch (ClassNotFoundException e1) {
// TODO Auto-generated catch block
e1.printStackTrace();
} catch (InstantiationException e1) {
// TODO Auto-generated catch block
e1.printStackTrace();
} catch (IllegalAccessException e1) {
// TODO Auto-generated catch block
e1.printStackTrace();
}
if (bean instanceof ProxyFactoryBean) {
Object proxy = null;
ProxyFactoryBean proxyFactoryBean = (ProxyFactoryBean) bean;
try {
Advice advice = (Advice) Class.forName(
prop.getProperty(name + ".advice")).newInstance();
Object target = Class.forName(
prop.getProperty(name + ".target")).newInstance();
proxyFactoryBean.setAdvice(advice);
proxyFactoryBean.setTarget(target);
proxy = proxyFactoryBean.getProxy();
} catch (InstantiationException e) {
// TODO Auto-generated catch block
e.printStackTrace();
} catch (IllegalAccessException e) {
// TODO Auto-generated catch block
e.printStackTrace();
} catch (ClassNotFoundException e) {
// TODO Auto-generated catch block
e.printStackTrace();
}
return proxy;
}
return bean;
}
}

复制代码

package com.itheima.day03.aopframework;
import java.lang.reflect.InvocationHandler;
import java.lang.reflect.Method;
import java.lang.reflect.Proxy;
import java.util.Collection;
import com.itheima.day03.Advice;
public class ProxyFactoryBean {
private Advice advice;
private Object target;
public Advice getAdvice() {
return advice;
}
public void setAdvice(Advice advice) {
this.advice = advice;
}
public Object getTarget() {
return target;
}
public void setTarget(Object target) {
this.target = target;
}
public Object getProxy() {
Object proxy = Proxy.newProxyInstance(target.getClass()
.getClassLoader(),
/* new Class[] { Collection.class }, */
target.getClass().getInterfaces(), new InvocationHandler() {
@Override
public Object invoke(Object proxy, Method method, Object[] args)
throws Throwable {
advice.beforeMethod(method);
Object retVal = method.invoke(target, args);
advice.afterMethod(method);
return retVal;
}
});
return proxy;
}
}

复制代码

package com.itheima.day03.aopframework;
import java.io.InputStream;
public class AopFrameWorkTest {
/**
* @param args
*/
public static void main(String[] args) {
// TODO Auto-generated method stub
InputStream is=AopFrameWorkTest.class.getResourceAsStream("config.properties");
Object bean=new BeanFactory(is).getBean("xxx");
System.out.println(bean.getClass().getName());
}
}

复制代码

package com.itheima.day03;
import java.lang.reflect.Method;
public interface Advice {
public void beforeMethod(Method method);
public void afterMethod(Method method);
}

复制代码

#xxx=java.util.ArrayList
xxx=com.itheima.day03.aopframework.ProxyFactoryBean
xxx.advice=com.itheima.day03.MyAdvice
xxx.target=java.util.ArrayList

复制代码