演示用eclipse自动生成 ReflectPoint类的setter和getter方法。

直接new一个PropertyDescriptor对象的方式来让大家了解JavaBean API的价值，

先用一段代码读取JavaBean的属性，然后再用一段代码设置JavaBean的属性。

演示用eclipse将读取属性和设置属性的流水帐代码分别抽取成方法：

只要调用这个方法，并给这个方法传递了一个对象、属性名和设置值，它就能完成属性修改的功能。

得到BeanInfo最好采用“obj.getClass()”方式，而不要采用“类名.class”方式，这样程序更通用。

采用遍历BeanInfo的所有属性方式来查找和设置某个RefectPoint对象的x属性。在程序中把一个类当作JavaBean来

看，就是调用IntroSpector.getBeanInfo方法， 得到的BeanInfo对象封装了把这个类当作JavaBean看的结果信息

package cn.itheima.day1;

import java.beans.BeanInfo;

import java.beans.IntrospectionException;

import java.beans.Introspector;

import java.beans.PropertyDescriptor;

import java.lang.reflect.InvocationTargetException;

import java.lang.reflect.Method;

import org.apache.commons.beanutils.BeanUtils;

import org.apache.commons.beanutils.PropertyUtils;

public class IntroSPectorTest {

	public static void main(String[] args) throws Exception{

		ReflectPoint pt1 = new ReflectPoint(3,5);;

		String propertyName = "x";

		Object retVal = getProperty(pt1, propertyName);

		System.out.println(retVal);

		Object value = 7;

		setProperties(pt1, propertyName, value);

		System.out.println(BeanUtils.getProperty(pt1,"x"));

		BeanUtils.setProperty(pt1,"x","9");

		System.out.println(BeanUtils.getProperty(pt1,"x"));

		//java7新特性。

		//Map map =(name:"cuizhaojin",age:18);

		//BeanUtils.setProperty(map, "name", "cuizhao");

		BeanUtils.setProperty(pt1,"birthday.time","2014"); 

		String birthday = BeanUtils.getProperty(pt1,"birthday.time"); 

		System.out.println(birthday); 

		PropertyUtils.setProperty(pt1,"x",9);

		System.out.println(PropertyUtils.getProperty(pt1, "x").getClass());

	}

	private static void setProperties(Object pt1, String propertyName, Object value) throws IntrospectionException, IllegalAccessException, InvocationTargetException {

		PropertyDescriptor pd2 = new PropertyDescriptor(propertyName,pt1.getClass());

		Method methodSetX =pd2.getWriteMethod();

		methodSetX.invoke(pt1,value);

	}

	private static Object getProperty(Object pt1, String propertyName) throws Exception

		/*throws IntrospectionException, IllegalAccessException, InvocationTargetException {

		PropertyDescriptor pd = new PropertyDescriptor(propertyName,pt1.getClass());

		Method methodGetX =pd.getReadMethod();

		Object retVal = methodGetX.invoke(pt1);*/{

		BeanInfo beanInfo = Introspector.getBeanInfo(pt1.getClass());

		PropertyDescriptor[] pds = beanInfo.getPropertyDescriptors();

		Object retVal = null;

		for(PropertyDescriptor pd: pds)

		{

			if(pd.getName().equals(propertyName))

			{

				Method methodGetX  = pd.getReadMethod();

				retVal = methodGetX.invoke(pt1);

				break;

			}

		}

		return retVal;

	}

}