30_张孝祥_Java基础加强_对JavaBean的简单内省操作.avi
l 代码演示1：
import java.beans.PropertyDescriptor;
import java.lang.reflect.Method;
public class IntroSpectorTest {
public static void main(String[] args)throws Exception {
ReflectPoint pt1 = new ReflectPoint(3, 5);
String propertyName = "x";
/*把下面代码标注<1>的，但是没声明要注释的代码选中后，
* 按快捷键ctrl+shift+T，选Extract Methoda可重构一个getProperty方法。
* */
PropertyDescriptor pd = new PropertyDescriptor(propertyName,ReflectPoint.class);//<1>
Class clazz = pd.getPropertyType();//<1>
System.out.println(clazz.toString());//<1>注释
Method methodW = pd.getWriteMethod();
System.out.println(methodW);
Object setVal = methodW.invoke(pt1,6);//因为set方法五返回值，这里invoke方法会返回null。
System.out.println(setVal);
Method methodR = pd.getReadMethod();//<1>
System.out.println(methodR);//注释
Object retVal = methodR.invoke(pt1);//注意，x的值改变了，变为：6。<1>
//Object retVal =methodR.invoke(pt1,null);//当方法的形参为空时，形参也可以用null表示。
System.out.println(retVal);
}
}
l 重构后的方法演示：
public class IntroSpectorTest {
public static void main(String[] args)throws Exception {
ReflectPoint pt1 = new ReflectPoint(3,5);
String propertyName = "x";
//"x"-->"X"-->"getX"-->MethodGetX-->
Object retVal = getProperty(pt1, propertyName);
System.out.println(retVal);
Object value = 7;
setProperties(pt1, propertyName, value);
System.out.println(BeanUtils.getProperty(pt1,"x").getClass().getName());
BeanUtils.setProperty(pt1, "x", "9");
//System.out.println(pt1.getX());
/*
//java7的新特性
Map map = {name:"zxx",age:18};
BeanUtils.setProperty(map, "name", "lhm");
*/
BeanUtils.setProperty(pt1, "birthday.time", "111");// //setProperty方法可以设置属性的级联属性（即属性的属性..）
System.out.println(BeanUtils.getProperty(pt1,"birthday.time"));
PropertyUtils.setProperty(pt1, "x", 9);
System.out.println(PropertyUtils.getProperty(pt1,"x").getClass().getName());
}
private static void setProperties(Object pt1, String propertyName,
Object value) throws IntrospectionException,
IllegalAccessException, InvocationTargetException {
PropertyDescriptor pd2 = newPropertyDescriptor(propertyName,pt1.getClass());
Method methodSetX = pd2.getWriteMethod();
methodSetX.invoke(pt1,value);
}
private static Object getProperty(Object pt1, String propertyName)
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;
}
}