Java Reflection Beans Property API

Question

Is there any standard way to access Java Bean Property like

class A {    private String name;     public void setName(String name){        this.name = name;    }     public String getName(){        return this.name;    }  } 

So can I access this java bean property name using Reflection API so that when I change the value of property the methods of getName and setName are called automatically when I set and get values of that property

Answer 1

You question is very unclear, but if I get it:

Yes. The java.beans package has the so called Introspector. There you can read the properties of a bean.

BeanInfo info = Introspector.getBeanInfo(Bean.class); PropertyDescriptor[] pds = info.getPropertyDescriptors(); 

You can find the desired PropertyDescriptor by its name and you can call getReadMethod().invoke(..)

Answer 2

What you need is the BeanInfo / Introspector mechanism (see Bozho's answer). However, it's hell to use this directly, so you can use one of the Libraries that offer property-based access. The best-known is probably Apache Commons / BeanUtils (another one is Spring's BeanWrapper abstraction)

Example code:

A someBean = new A();  // access properties as Map Map<String, Object> properties = BeanUtils.describe(someBean); properties.set("name","Fred"); BeanUtils.populate(someBean, properties);  // access individual properties String oldname = BeanUtils.getProperty(someBean,"name"); BeanUtils.setProperty(someBean,"name","Barny");