Java基础之实现类似spring的可配置的AOP

#xxx=java.util.ArrayList
xxx=javaplay.day3.aopframework.ProxyFactoryBean
xxx.advice=javaplay.day3.MyAdvice
xxx.target=java.util.ArrayList

 

package javaplay.day3.aopframework;

import java.lang.reflect.InvocationHandler;
import java.lang.reflect.Method;
import java.lang.reflect.Proxy;

import javaplay.day3.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 proxy3 = 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 {
						/*
						 * long beginTime = System.currentTimeMillis(); Object
						 * retVal = method.invoke(target, args); long endTime =
						 * System.currentTimeMillis();
						 * System.out.println(method.getName() +
						 * " running time is " + (endTime - beginTime)); return
						 * retVal;
						 */

						advice.beforeMethod(method);
						Object retVal = method.invoke(target, args);
						advice.afterMethod(method);

						return retVal;
					}

				});
		return proxy3;
	}

}

package javaplay.day3.aopframework;

import java.io.IOException;
import java.io.InputStream;
import java.util.Properties;

import javaplay.day3.Advice;

public class BeanFactory {

	Properties props = new Properties();

	public BeanFactory(InputStream ips) {
		try {
			this.props.load(ips);
		} catch (IOException e) {
		}
	}

	public Object getBean(String name) {
		String className = props.getProperty(name);
		Object bean = null;
		try {
			Class clazz = Class.forName(className);
			// 对于javabena来说，必须有一个不带参数的构造方法，下面这行就是原因
			// 别人创建javabean的实例对象时用的就是下面这行
			bean = clazz.newInstance();
		} catch (Exception e) {
			e.printStackTrace();
		}
		if (bean instanceof ProxyFactoryBean) {
			Object proxy = null;
			ProxyFactoryBean proxyFactoryBean = (ProxyFactoryBean) bean;
			try {
				Advice advice = (Advice) Class.forName(props.getProperty(name + ".advice")).newInstance();
				Object target = Class.forName(props.getProperty(name + ".target")).newInstance();
				proxyFactoryBean.setAdvice(advice);
				proxyFactoryBean.setTarget(target);
				proxy = proxyFactoryBean.getProxy();
			} catch (Exception e) {
				e.printStackTrace();
			}
			return proxy;
		}
		return bean;
	}
}

package javaplay.day3.aopframework;

import java.io.InputStream;
import java.util.Collection;

public class AopFrameworkTest {
	public static void main(String[] args) {
		InputStream ips = AopFrameworkTest.class.getResourceAsStream("config.properties");
		Object bean = new BeanFactory(ips).getBean("xxx");
		System.out.println(bean.getClass().getName());
		((Collection) bean).clear();
		// config.properties文件第一行注释时输出：com.sun.proxy.$Proxy0
		// config.properties文件第二行注释时输出：java.util.ArrayList
		// 代理不代理只需要在配置文件里配置就行了，这就是spring的精髓；spring两大核心特性：bean工厂和aop框架
	}
}