spring 之 簡單的Aop框架（自己實現）

spring 之 簡單的Aop框架（自己實現）

首先定義一個 config.properties
#xxx=java.util.ArrayList
xxx=com.study.springenvironment.javastudy.proxy.aopframework.ProxyFactoryBean
xxx.advice=com.study.springenvironment.javastudy.proxy.MyAdvice
xxx.target=java.util.ArrayList

//簡單的反射創建實例的工廠
public class BeanFactory {
	Properties props = new Properties();
	public BeanFactory(InputStream ips){
		try {
			props.load(ips);
		} catch (IOException e) {
			// TODO Auto-generated catch block
			e.printStackTrace();
		}
	}
	
	public Object getBean(String name){
		String className = props.getProperty(name);
		Object bean = null;
		try {
			Class clazz = Class.forName(className);
			bean = clazz.newInstance();
		} catch (Exception e) {
			// TODO Auto-generated catch block
			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) {
				// TODO Auto-generated catch block
				e.printStackTrace();
			}
			return proxy;
		}
		return bean;
	}
}

//簡單的代理工具bean合集
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() {
		return ProxyUtil.getProxy(target,advice);
	}

}

//獲取java 代理對象的工具類
public class ProxyUtil {
    public static Object getProxy(final Object target,final Advice advice) {
//        System.getProperties().put("sun.misc.ProxyGenerator.saveGeneratedFiles", "true");//生成的代理class對象在工程目錄下的com\sun\proxy
        Object proxy;
        proxy= Proxy.newProxyInstance(
                target.getClass().getClassLoader(),
                target.getClass().getInterfaces(),
                new InvocationHandler(){
                    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;
    }

}

import java.lang.reflect.Method;
//執行方法前需要執行的方法
public interface Advice {
	void beforeMethod(Method method);
	void afterMethod(Method method);
}

import java.lang.reflect.Method;
//簡單實現一個統計方法執行耗時統計的advice
public class MyAdvice implements Advice {
	long beginTime = 0;
	public void afterMethod(Method method) {
		// TODO Auto-generated method stub
		System.out.println("after method:" + method.getName());
		long endTime = System.currentTimeMillis();
		System.out.println(method.getName() + " running time of " + (endTime - beginTime));

	}

	public void beforeMethod(Method method) {
		// TODO Auto-generated method stub
		System.out.println("before method:" + method.getName());
		beginTime = System.currentTimeMillis();
	}

}

public class AopFrameworkTest {

	/**
	 * @param args
	 */
	public static void main(String[] args) throws Exception {
		// TODO Auto-generated method stub
		InputStream ips = AopFrameworkTest.class.getResourceAsStream("config.properties");
		Object bean = new BeanFactory(ips).getBean("xxx");
		System.out.println(bean.getClass().getName());
		((Collection)bean).clear();
	}

}