2段简单的JavaBean代码演示了简单内省操作以及复杂内省操作  。

1、简单内省操作

package me.test;

import java.lang.reflect.*;

import java.beans.IntrospectionException;

import java.beans.PropertyDescriptor;

public class IntroSpectorTest

{

   public  static void main(String []args) throws IntrospectionException, IllegalArgumentException, IllegalAccessException, InvocationTargetException

   {

    JavaBeanTest t=new JavaBeanTest() ;

    t.setX(10);

    PropertyDescriptor d=new PropertyDescriptor("X",JavaBeanTest.class);

    setProperty(t, d);

    Object val = getProperty(t, d);

    System.out.println(val);

   

   }

private static Object getProperty(JavaBeanTest t, PropertyDescriptor d)

  throws IllegalAccessException, InvocationTargetException {

 Method mr=d.getReadMethod()  ;

    Object val=mr.invoke(t);

 return val;

}

private static void setProperty(JavaBeanTest t, PropertyDescriptor d)

  throws IllegalAccessException, InvocationTargetException {

    Method mw=d.getWriteMethod()  ;

    mw.invoke(t, 5) ;

}

}

class  JavaBeanTest

{

 private int x  ;

 public void setX(int x)

 {

  this.x=x ;

 }

 public int getX()

  

 {

  return this.x ;

 }

}

 

2、复杂内省操作   BeanInfo类   Introspector类的使用

package me.test;

import java.lang.reflect.*;

import java.beans.BeanInfo;

import java.beans.IntrospectionException;

import java.beans.Introspector;

import java.beans.PropertyDescriptor;

public class IntroSpectorTest

{

   public  static void main(String []args) throws IntrospectionException, IllegalArgumentException, IllegalAccessException, InvocationTargetException

   {

    JavaBeanTest t=new JavaBeanTest(10) ;

    PropertyDescriptor d=new PropertyDescriptor("x",JavaBeanTest.class);

    setProperty(t, d);

    Object val = getProperty(t, d);

    System.out.println(val);

   

   }

private static Object getProperty(JavaBeanTest t, PropertyDescriptor d)

  throws IllegalAccessException, InvocationTargetException, IntrospectionException {

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

 PropertyDescriptor  pt[]=beanInfo.getPropertyDescriptors() ;

  for(PropertyDescriptor tem:pt)

  {

   if(tem.getName().equals(d.getName()))

     {

             Method mr=tem.getReadMethod() ;

             Object val=mr.invoke(t) ;

             return val ;

     }

  }

 return null;

}

private static void setProperty(JavaBeanTest t, PropertyDescriptor d)

  throws IllegalAccessException, InvocationTargetException, IntrospectionException {

   

    BeanInfo beanInfo=Introspector.getBeanInfo(t.getClass() ) ; //把JavaBeanTest的对象当做JavaBean看有什么信息封装在BeanInfo中

    PropertyDescriptor [] pd=beanInfo.getPropertyDescriptors() ;  //Get All Properties From BeanInfo Class

    for(PropertyDescriptor tem:pd)

    {  

     if(tem.getName().equals(d.getName()))

     {

      Method mw=tem.getWriteMethod() ;

      mw.invoke(t, 50)  ;

      break ;

     }

    }

}

}

class  JavaBeanTest

{

 private int x  ;

 public JavaBeanTest(int x)

 {

  this.x=x ;

 }

 public void setX(int x)

 {

  this.x=x ;

 }

 public int getX()

  

 {

  return this.x ;

 }

}