实现类似于Spring的可配置的AOP框架

╰半橙微兮° 2022-06-17 11:55 192阅读 0赞

AopFrameworkTest.java

import java.io.InputStream;
    import java.util.Collection;
    
    public class AopFrameworkTest {
    
    	public static void main(String[] args) {
    		InputStream is = AopFrameworkTest.class.getResourceAsStream("config.properties");
    		BeanFactory beanFactory = new BeanFactory(is);
    		Object obj = beanFactory.getBean("testBean");
    		System.out.println(obj.getClass().getName());
    		Collection collection = (Collection)obj;
    		collection.add("zhuang");
    		collection.add("alex");
    		System.out.println(collection.size());
    		
    	}
    
    }

BeanFactory.java

import java.io.IOException;
    import java.io.InputStream;
    import java.util.Properties;
    
    public class BeanFactory {
    	private Properties prop =new Properties();
    	public BeanFactory(InputStream is){
    		try {
    			this.prop.load(is);
    		} catch (IOException e) {
    			e.printStackTrace();
    		}
    	}
    	
    	public Object getBean(String beanName){
    		String className = this.prop.getProperty(beanName);
    		Object beanObj = null;
    		try {
    			beanObj = Class.forName(className).newInstance();
    			Object proxy;
    			if(beanObj instanceof ProxyFactoryBean){
    				ProxyFactoryBean proxyFactoryBean = (ProxyFactoryBean)beanObj;
    				proxyFactoryBean.setTarget(Class.forName(this.prop.getProperty(beanName+".target")).newInstance());
    				proxyFactoryBean.setAdvice((MyAdvice)Class.forName(this.prop.getProperty(beanName+".advice")).newInstance());
    				proxy = proxyFactoryBean.getProxy();
    				return proxy ;
    			}
    		} catch (InstantiationException e) {
    			e.printStackTrace();
    		} catch (IllegalAccessException e) {
    			e.printStackTrace();
    		} catch (ClassNotFoundException e) {
    			e.printStackTrace();
    		}
    		return beanObj;
    	}
    }

ProxyFactoryBean.java

import java.lang.reflect.InvocationHandler;
    import java.lang.reflect.Method;
    import java.lang.reflect.Proxy;
    
    public class ProxyFactoryBean {
    	private Object target ;
    	private MyAdvice advice ;
    	
    	public Object getTarget() {
    		return target;
    	}
    
    	public Object getAdvice() {
    		return advice;
    	}
    
    	public void setTarget(Object target) {
    		this.target = target;
    	}
    
    	public void setAdvice(MyAdvice advice) {
    		this.advice = advice;
    	}
    
    	public Object getProxy(){
    		Object proxyBean = Proxy.newProxyInstance(this.target.getClass().getClassLoader(),this.target.getClass().getInterfaces(), new InvocationHandler(){
    			public Object invoke(Object proxy, Method method, Object[] args)
    					throws Throwable {
    				advice.beforeMethod();
    				Object obj = method.invoke(target, args);
    				advice.afterMethod();
    				return obj;
    			}
    		}) ;
    		
    		return proxyBean;
    	}
    }

Advice.java

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

MyAdvice.java

public class MyAdvice implements Advice{
    
    	public void afterMethod() {
    		System.out.println("after method...");
    		
    	}
    
    	public void beforeMethod() {
    		System.out.println("before method...");
    		
    	}
    	
    }

config.properties

testBean=javase.aopframework.ProxyFactoryBean
    testBean.advice=javase.aopframework.MyAdvice
    testBean.target=java.util.ArrayList