內容
java基礎鞏固筆記 - 實現AOP功能的封裝與配置的小框架
設計(目錄):
XXX = java.util.ArrayList中
代碼
Advice介面
MyAdvice類
BeanFactory類
ProxyFactoryBean類
AopFrameWorkTest類
輸出
本文通過是動態代理實現的AOP功能的封裝與配置的小框架.加深對動態代理和AOP編程的理解
設計
根據配置文件的鍵xxx對應的值(類全名)創建相應類的對象。
當且僅當xxx對應的值為com.iot.proxy.aopframework.ProxyFactoryBean時,則生成相應的動態代理類對象。代理對象的目標類和通知實現類分別由xxx.target和xxx.advice配置
配置文件
config.propertiest位於aopframework包下
xxx代表要載入的類
xxx.advice代表通知介面的某個實現類
xxx.target代表委託類
#xxx=java.util.ArrayList
xxx=com.iot.proxy.aopframework.ProxyFactoryBean
xxx.advice=com.iot.proxy.MyAdvice
xxx.target=java.util.ArrayList
包:com.iot.proxy.aopframework,有如下幾個類/介面:
BeanFactory,用於讀取配置文件,根據配置創建相應的對象
ProxyFactoryBean,用於生成代理對象,含有兩個私有屬性:目標和通知
Advice,通知介面,用於把切面的代碼以對象的形式傳遞給InvocationHandler的的invoke方法
MyAdvice,Advice介面的一個實現類,列印執行方法前的時間及執行耗時
AopFrameWorkTest,測試效果
代碼
Advice介面
package com.iot.proxy.aopframework;
import java.lang.reflect.Method;
/**
* Created by brian on 2016/2/2.
*/
public interface Advice {
void beforeMethod(Method method);
void aftereMethod(Method method);
}
MyAdvice類
package com.iot.proxy.aopframework;
import java.lang.reflect.Method;
/**
* Created by brian on 2016/2/2.
*/
public class MyAdvice implements Advice{
long beginTime = 0 ;
@Override
public void beforeMethod(Method method) {
System.out.println(method.getName+" before at "+beginTime);
beginTime = System.currentTimeMillis;
}
@Override
public void aftereMethod(Method method) {
long endTime = System.currentTimeMillis;
System.out.println(method.getName+" cost total "+ (endTime-beginTime));
}
}
BeanFactory類
package com.iot.proxy.aopframework;
import java.io.IOException;
import java.io.InputStream;
import java.util.Properties;
/**
* Created by brian on 2016/2/2.
*/
public class BeanFactory {
Properties properties = new Properties;
public BeanFactory(InputStream inputStream){
try {
properties.load(inputStream);
} catch (IOException e) {
e.printStackTrace;
}
}
public Object getBean(String name){
String className = properties.getProperty(name);
Object bean = null;
try {
Class clazz = Class.forName(className);
bean = clazz.newInstance;
} catch (ClassNotFoundException e) {
e.printStackTrace;
} catch (InstantiationException e) {
e.printStackTrace;
} catch (IllegalAccessException e) {
e.printStackTrace;
}
if (bean instanceof ProxyFactoryBean){
ProxyFactoryBean proxyFactoryBean = (ProxyFactoryBean)bean;
Advice advice = null;
Object target = null;
try {
advice = (Advice) Class.forName(properties.getProperty(name+".advice")).newInstance;
target = Class.forName(properties.getProperty(name+".target")).newInstance;
} catch (InstantiationException e) {
e.printStackTrace;
} catch (IllegalAccessException e) {
e.printStackTrace;
} catch (ClassNotFoundException e) {
e.printStackTrace;
}
proxyFactoryBean.setAdvice(advice);
proxyFactoryBean.setTarget(target);
Object proxy = ((ProxyFactoryBean) bean).getProxy;
return proxy;
}
return bean;
}
}
ProxyFactoryBean類
package com.iot.proxy.aopframework;
import java.lang.reflect.InvocationHandler;
import java.lang.reflect.Method;
import java.lang.reflect.Proxy;
/**
* Created by brian on 2016/2/3.
*/
public class ProxyFactoryBean {
private Object target;
private Advice advice;
public Object getProxy{
Object proxy = Proxy.newProxyInstance(
target.getClass.getClassLoader,
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.aftereMethod(method);
return retVal;
}
}
);
return proxy;
}
public Object getTarget {
return target;
}
public void setTarget(Object target) {
this.target = target;
}
public Advice getAdvice {
return advice;
}
public void setAdvice(Advice advice) {
this.advice = advice;
}
}
AopFrameWorkTest類
package com.iot.proxy.aopframework;
import java.io.InputStream;
import java.util.Collection;
/**
* Created by brian on 2016/2/3.
*/
public class AopFrameWorkTest {
public static void main(String args) {
InputStream inputStream = AopFrameWorkTest.class.getResourceAsStream("config.properties");
Object bean = new BeanFactory(inputStream).getBean("xxx");
System.out.println(bean.getClass.getName);
((Collection) bean).clear;
}
}
輸出
配置
xxx=com.iot.proxy.aopframework.ProxyFactoryBean
輸出為:
com.sun.proxy.$Proxy0clear before at 0clear cost total 0
配置
xxx=java.util.ArrayList
輸出為:
java.util.ArrayList
可以看出,只改變配置文件,就可改變代碼的運行結果,從而達到靈活的效果