黑马程序员_java高级篇代理Day14(下)

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这篇主要是用代码来试看看代理类的实现，以及AOP编程，BeanFactory的应用

#代理类的实现#

package day13;import java.awt.event.InvocationEvent;import java.lang.reflect.Constructor;import java.lang.reflect.InvocationHandler;import java.lang.reflect.Method;import java.lang.reflect.Proxy;import java.util.ArrayList;import java.util.Collection;public class ProxyTest {/** * 动态代理的实现 */public static void main(String[] args) throws SecurityException, Exception {// TODO Auto-generated method stub         Class classProxy=Proxy.getProxyClass(Collection.class.getClassLoader(),Collection.class); Constructor[]  constructors  =  classProxy.getConstructors(); System.out.println("-----classProxy得到构造开始--------"); for(Constructor  constructor: constructors) { String name=constructor.getName(); StringBuilder strBd=new StringBuilder(name); strBd.append("("); Class[] classPars=constructor.getParameterTypes(); for(Class classPar:classPars) {strBd.append(classPar.getName()).append(',');  } if(classPars.length!=0&&classPars!=null) strBd.deleteCharAt(strBd.length()-1); strBd.append(")"); System.out.println(strBd.toString()); }  System.out.println("-----method开始--------"); Method[]  Methods  = classProxy.getMethods(); for(Method  method: Methods) { String name=method.getName(); StringBuilder strBd=new StringBuilder(name); strBd.append("("); Class[] classPars=method.getParameterTypes(); for(Class classPar:classPars) {strBd.append(classPar.getName()).append(',');  } if(classPars.length!=0&&classPars!=null) strBd.deleteCharAt(strBd.length()-1); strBd.append(")"); System.out.println(strBd.toString()); }  System.out.println("-----creat object开始--------"); //1,构造方法 Constructor  constructor  =  classProxy.getConstructor(InvocationHandler.class); class myinvocation implements InvocationHandler {public Object invoke(Object proxy, Method method, Object[] args)throws Throwable {// TODO Auto-generated method stubreturn null;}  } //new 对象 Collection c= (Collection) constructor.newInstance(new InvocationHandler(){public Object invoke(Object proxy, Method method, Object[] args)throws Throwable {// TODO Auto-generated method stubreturn null;}   });  //，当我们程序就到这时，调用方法应注意，当我们调用有返回值得方法时，会报错！      c.clear();          //内部类要想访问target，必须将其定义为final的 final  ArrayList target=new ArrayList(); //其实 getProxy是我们重构出来的，这个代码也可以放在这里，只是这样看起来更加好     Collection c1 = (Collection) getProxy(target,new MyAdviser());          //新建了对象后，我们就可以加了，同时这个对象就是ArrayList      c1.add("s");      c1.add("dsd");      c1.add("ds");      System.out.println(c1.size());}public static Object getProxy(final Object target,final Advise advise) {Collection c1=(Collection) Proxy.newProxyInstance(/*Collection.class.getClassLoader()*/target.getClass().getClassLoader(),/*new Class[]{Collection.class}*/target.getClass().getInterfaces(),new InvocationHandler(){    public Object invoke(Object proxy, Method method, Object[] args)throws Throwable {// TODO Auto-generated method stubadvise.beforeMethod(method);    //Long startTime=System.currentTimeMillis();Object val= method.invoke(target,args);advise.afterMethod(method);//Long endTime=System.currentTimeMillis();        return val;              }    });return c1;}}

#中间的接口Advise#

package day13;import java.lang.reflect.Method;public interface Advise {public void beforeMethod(Method m);public void afterMethod(Method m);}

#实现了Advise接口的类#

package day13;import java.lang.reflect.Method;public class MyAdviser implements Advise {/** * @param args */ long startTime=0;public static void main(String[] args) {// TODO Auto-generated method stub}public void afterMethod(Method m) {// TODO Auto-generated method stubLong endTime=System.currentTimeMillis();System.out.println(m.getName()+":"+(endTime-startTime));}public void beforeMethod(Method m) {// TODO Auto-generated method stub startTime=System.currentTimeMillis();}}

#使用AOP Bean模仿Spring原理#

#AopTest#

package day13;import java.io.IOException;import java.io.InputStream;public class AopTest {/** * @param args * @throws Exception  */public static void main(String[] args) throws Exception {// TODO Auto-generated method stubInputStream is=AopTest.class.getResource("config.properties").openStream();

                //调用方法Object bean=new BeanFactory(is).getBean("xxx");System.out.println(bean.getClass().getName());}}

#BeanFactory#

这里要判断一下这个对象是否在ProxyFactoryBean中，如果不在直接不执行if，返回对象，如果是一个代理，那就要执行if

package day13;import java.io.IOException;import java.io.InputStream;import java.util.Properties;public class BeanFactory {/** * @param args */public static void main(String[] args) {// TODO Auto-generated method stub}Properties prop=new Properties();public BeanFactory(InputStream is) throws Exception{prop.load(is);}public Object getBean(String name) throws Exception{String className=prop.getProperty(name);System.out.println("helo"+className);Object obj=Class.forName(className).newInstance();

                //这里要判断一下这个对象是否在ProxyFactoryBean中，如果不在直接不执行if，返回对象，如果是一个代理，那就要执行ifif(obj instanceof ProxyFactoryBean){  Object proxy=null;ProxyFactoryBean proxyfactoryBean=(ProxyFactoryBean)obj;Object target=Class.forName(prop.getProperty(name+".target")).newInstance();Advise advise=(Advise) Class.forName(prop.getProperty(name+".advise")).newInstance();proxyfactoryBean.setTarget(target);proxyfactoryBean.setAdvise(advise);       proxy=((ProxyFactoryBean)obj).getProxy();      return proxy;}return obj;}}

#ProxyFactoryBean#

我老疑惑怎么不要构造方法把那两个参数target，advise传进来，原来他们都是静态的成员变量。

package day13;import java.lang.reflect.InvocationHandler;import java.lang.reflect.Method;import java.lang.reflect.Proxy;import java.util.Collection;public class ProxyFactoryBean {/** * @param args */private static Object target;private static Advise advise;public static void main(String[] args) {// TODO Auto-generated method stub}public static Object getProxy() {Collection c1=(Collection) Proxy.newProxyInstance(/*Collection.class.getClassLoader()*/target.getClass().getClassLoader(),/*new Class[]{Collection.class}*/target.getClass().getInterfaces(),new InvocationHandler(){    public Object invoke(Object proxy, Method method, Object[] args)throws Throwable {// TODO Auto-generated method stub//其实我们是把以前写这里的代码，都抽出来，写到advise里面去了advise.beforeMethod(method);    //Long startTime=System.currentTimeMillis();Object val= method.invoke(target,args);advise.afterMethod(method);//Long endTime=System.currentTimeMillis();        return val;              }    });return c1;}public Object getTarget() {return target;}public void setTarget(Object target) {this.target = target;}public static Advise getAdvise() {return advise;}public static void setAdvise(Advise advise) {ProxyFactoryBean.advise = advise;}}

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