List bean property names

Ilias TsagklisNovember 11th, 2012Last Updated: October 25th, 2013

0 450 1 minute read

With this example we are going to demonstrate how to list the names of a bean’s properties. We are using the PropertyDescriptor, a class that describes one property that a Java Bean exports via a pair of accessor methods. We are also using the Introspector class, that provides a standard way for tools to learn about the properties, events, and methods supported by a target Java Bean. In short, to list the names of a bean’s properties you should:

Create a simple class, like Bean class in the example. It has two String properties and getters and setters for the properties.
Use getBeanInfo(Class<?> beanClass) API method of Introspector on the Bean to learn about all its properties, exposed methods, and events. The method returns a BeanInfo, that provides explicit information about the methods, properties, events, etc, of the bean.
Use getPropertyDescriptors() API method of BeanInfo to get a list with all the PropertyDescriptors for all properties of the bean.
Use getName() and getPropertyType() API method of PropertyDescriptor to get name and the Java type of each property.

Let’s take a look at the code snippet that follows:

package com.javacodegeeks.snippets.core;

import java.beans.BeanInfo;
import java.beans.Introspector;
import java.beans.PropertyDescriptor;

public class ListBeanPropertyNames {
	
	public static void main(String[] args) throws Exception {
		
		BeanInfo beanInfo = Introspector.getBeanInfo(Bean.class);
		
	    PropertyDescriptor[] descriptors = beanInfo.getPropertyDescriptors();
	    
	    for (int i=0; i<descriptors.length; i++) {
	    	String propName = descriptors[i].getName();
	    	Class<?> propType = descriptors[i].getPropertyType();
	    	System.out.println("Property with Name: " + propName + " and Type: " + propType);
	    }
		
	}
	
	public static class Bean {
		
		// Property property1
		private String property1;
	    // Property property2
		private int property2;
	    
		public String getProperty1() {
			return property1;
		}
		public void setProperty1(String property1) {
			this.property1 = property1;
		}
		
		public int getProperty2() {
			return property2;
		}
		public void setProperty2(int property2) {
			this.property2 = property2;
		}
	    
	}

}

Output:

Property with Name: class and Type: class java.lang.Class
Property with Name: property1 and Type: class java.lang.String
Property with Name: property2 and Type: int

This was an example of how to list the names of a bean’s properties in Java.