how to read object attribute dynamically in java?

Question

Is there any way to read and print the object attribute dynamically(Java) ? for example if I have following object

public class A{
  int age ;
  String name;
           


        

Answer 1

Using org.apache.commons.beanutils.PropertyUtils we can do this. If the proper getters and setters are defined for the bean we can also dynamically set the value:

import org.apache.commons.beanutils.PropertyUtils;
import java.beans.PropertyDescriptor;

public class PropertyDescriptorTest {

    public static void main(String[] args) {

        // Declaring and setting values on the object
        AnyObject anObject = new AnyObject();
        anObject.setIntProperty(1);
        anObject.setLongProperty(234L);
        anObject.setStrProperty("string value");

        // Getting the PropertyDescriptors for the object
        PropertyDescriptor[] objDescriptors = PropertyUtils.getPropertyDescriptors(anObject);

        // Iterating through each of the PropertyDescriptors
        for (PropertyDescriptor objDescriptor : objDescriptors) {
            try {
                String propertyName = objDescriptor.getName();
                Object propType = PropertyUtils.getPropertyType(anObject, propertyName);
                Object propValue = PropertyUtils.getProperty(anObject, propertyName);

                // Printing the details
                System.out.println("Property="+propertyName+", Type="+propType+", Value="+propValue);
            } catch (Exception e) {
                e.printStackTrace();
            }
        }

    }

}

To set the value of a particular property:

// Here we have to make sure the value is
// of the same type as propertyName
PropertyUtils.setProperty(anObject, propertyName, value);

Output will be:

Property=class, Type=class java.lang.Class, Value=class genericTester.AnyObject
Property=intProperty, Type=int, Value=1
Property=longProperty, Type=class java.lang.Long, Value=234
Property=strProperty, Type=class java.lang.String, Value=string value