内省对象 用的少，被BeanUtils代替

类	描述
BeanInfo	对JavaBean进行描述的接口
Introspector	描述所有的JavaBean的成员类
PropertyDescriptor	描述的是JavaBean的属性类

shape.java

 package reflect;

 public class Shape {
     private int x=4;
     int y;
     protected int z;
     public int h;
     public Shape() {
     }
     public Shape(int x, Integer y) {
         super();
         this.x = x;
         this.y = y;

     }
     public Shape(int x, int y, int z, int h) {
         super();
         this.x = x;
         this.y = y;
         this.z = z;
         this.h = h;
     }
     public int getX() {
         return x;
     }
     public void setX(int x) {
         this.x = x;
     }
     public int getY() {
         return y;
     }
     public void setY(int y) {
         this.y = y;
     }
     public int getZ() {
         return z;
     }
     public void setZ(int z) {
         this.z = z;
     }
     public int getH() {
         return h;
     }
     public void setH(int h) {
         this.h = h;
     }
     @Override
     public String toString() {
         return "Shape [x=" + x + ", y=" + y + ", z=" + z + ", h=" + h
                 + ", getX()=" + getX() + ", getY()=" + getY() + ", getZ()="
                 + getZ() + ", getH()=" + getH() + ", getClass()=" + getClass()
                 + ", hashCode()=" + hashCode() + ", toString()="
                 + super.toString() + "]";
     }

 }

         Shape shape=new Shape();
         BeanInfo beaninfo=Introspector.getBeanInfo(Shape.class);
         PropertyDescriptor []pds=beaninfo.getPropertyDescriptors();
         //返回5个，其中还有一个是Object中的 getClass()和setClass()， 它是根据 getXxx和setXxx找的
         System.out.println(pds.length);
         PropertyDescriptor pd = pds[1];            //数组下标 按照字典顺序  第一个是 class、h、x、y、z
         System.out.println(pd.getName());
         Method setMethod=pd.getWriteMethod();
         System.out.println(setMethod.getName());
         setMethod.invoke(shape, 33);
         System.out.println(pds[1].getReadMethod().invoke(shape,null));

结果：

5
h
setH
33