动态代理的实现3-实现aop功能的封装和配置

女爷i 2022-06-10 04:59 74阅读 0赞

![1341063432_7338.jpg][]

//一个通告或建议的接口
    public interface Advice {
    	void afterMethod(Method method);
    	void beforeMethod(Method method);
    }

public class MyAdvice implements Advice{
    	private long start;
    	@Override
    	public void afterMethod(Method method) {
    		System.out.println("运行时间计算结束!!");
    		System.out.println("共耗时:"+(System.currentTimeMillis()-start));
    		System.out.println("------------------------");
    	}
    
    	@Override
    	public void beforeMethod(Method method) {
    		System.out.println("开始计算运行时间:");
    		start=System.currentTimeMillis();
    		System.out.println("所执行的方法:"+method.getName());
    	}
    }

Properties文件的配置
    #xxx=java.util.ArrayList
    xxx=aopframework.ProxyFactoryBean
    xxx.advice=aopframework.MyAdvice
    xxx.target=java.util.ArrayList

/**
     * 负责创建目标类或代理类的实例对象，并通过配置文件实现切换
     *
     */
    public class BeanFactory {
    	private Properties prop;
    	public BeanFactory(InputStream is){
    		prop=new Properties();
    		try {prop.load(is);
    		} catch (IOException e) {
    			e.printStackTrace();
    		}
    	}
    	public Object getBean(String propkey){
    		String className=prop.getProperty(propkey);
    		Object bean=null;
    		try {
    			bean=Class.forName(className).newInstance();
    			if(bean instanceof ProxyFactoryBean){
    				String adviceName=prop.getProperty(propkey+".advice");
    				String targetName=prop.getProperty(propkey+".target");
    				try {
    					Advice advice = (Advice) Class.forName(adviceName).newInstance();
    					Object target = Class.forName(targetName).newInstance();
    					ProxyFactoryBean beanproxy=(ProxyFactoryBean)bean;
    					beanproxy.setAdvice(advice);
    					beanproxy.setTarget(target);
    					bean=beanproxy.getProxy();
    				} catch (Exception e) {
    					e.printStackTrace();
    				}
    			}
    		} catch (Exception e) {
    			e.printStackTrace();
    		}
    		return bean;
    	}
    }

/**
     * 充当封装生成动态代理的工厂
     */
    public class ProxyFactoryBean {
    	private Advice advice;
    	private Object target;
    	public Object getProxy() {
    		Object coll=(Object) 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 obj=method.invoke(target, args);
    						advice.afterMethod(method);
    						return obj;
    					}
    				});
    		return coll;
    	}
    	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 class Test {
    	public static void main(String[] args) {
    		InputStream is=Test.class.getClassLoader().getResourceAsStream("config.properties");
    		BeanFactory factory=new BeanFactory(is);
    		Collection coll=(Collection) factory.getBean("xxx");
    		coll.add("aaa");
    		coll.add("222");
    		System.out.println(coll.size());
    	}
    	/**
    	 * 运行结果
    	           开始计算运行时间:
    		所执行的方法:add
    		运行时间计算结束!!
    		共耗时:0
    		------------------------
    		开始计算运行时间:
    		所执行的方法:add
    		运行时间计算结束!!
    		共耗时:0
    		------------------------
    		开始计算运行时间:
    		所执行的方法:size
    		运行时间计算结束!!
    		共耗时:0
    		------------------------
    		2
    	 */
    }

[1341063432_7338.jpg]: https://img-my.csdn.net/uploads/201206/30/1341063432_7338.jpg