關於Spring的代理問題

1.   設置一個BeanFactory

package com.proxy;

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


public class BeanFactory {
	 /*
	 * 從配置文件中讀取
	 */
	Properties props = new Properties();
	public BeanFactory(InputStream ips){
		try {
			props.load(ips);
		} catch (IOException e) {
			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) {
		
			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;
	}
}

2.  設置一個代理工廠 

package com.proxy;

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

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(),
				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 proxy3;
	}

}

3.   設置Advice接口

 

package com.proxy;

import java.lang.reflect.Method;

public  interface Advice {
	 void beforeMethod(Method method);
	 void afterMethod(Method method);
}

4. 實現Advice接口 

package com.proxy;

import java.lang.reflect.Method;

public class MyAdvice implements Advice {
	long beginTime = 0;
	public void afterMethod(Method method) {
		System.out.println("建議前");		
		long endTime = System.currentTimeMillis();
		System.out.println(method.getName() + " running time of " + (endTime - beginTime));

	}

	public void beforeMethod(Method method) {
	
		System.out.println("建議後！");
		beginTime = System.currentTimeMillis();
	}

}

5  寫好一個配置文件 config.properties

#直接指定類
#xxx=java.util.ArrayList
#指定代理類
xxx=com.proxy.ProxyFactoryBean
xxx.advice=com.proxy.MyAdvice
xxx.target=java.util.ArrayList

 

6. 寫一個測試類

package com.proxy;

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

public class AopFrameworkTest {
	/**測試是否能夠動態代理
	 * @param args
	 */
	public static void main(String[] args) throws Exception {
		
		InputStream ips = AopFrameworkTest.class.getResourceAsStream("config.properties");
		Object bean = new BeanFactory(ips).getBean("xxx");
		System.out.println(bean.getClass().getName());
		((Collection)bean).clear();
	}

}