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
Beanclass in the example. It has two String properties and getters and setters for the properties. - Use
getBeanInfo(Class<?> beanClass)API method of Introspector on theBeanto 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()andgetPropertyType()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.
