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