List bean property names

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.