In this example you’ll see how to read an indexed property of an object such as List or array. Using the PropertyUtils.getIndexedProperty() method we can do it easily. This method take the bean and the name of indexed property including the element to be read. Let’s see the example below for more details.

package org.kodejava.commons.beanutils;

import org.apache.commons.beanutils.PropertyUtils;
import org.kodejava.commons.beanutils.support.Track;
import org.kodejava.commons.beanutils.support.Record;

import java.util.ArrayList;
import java.util.List;

public class ReadIndexedProperty {
    public static void main(String[] args) {
        Record record = new Record();
        record.setId(1L);
        record.setTitle("Sgt. Pepper's Lonely Hearts Club Band");

        List<Track> tracks = new ArrayList<>();
        Track track1 = new Track();
        track1.setTitle("Sgt. Pepper's Lonely Hearts Club Band");

        Track track2 = new Track();
        track2.setTitle("With A Little Help From My Friends");

        Track track3 = new Track();
        track3.setTitle("Lucy In The Sky With Diamonds");

        tracks.add(track1);
        tracks.add(track2);
        tracks.add(track3);

        record.setTracks(tracks);

        try {
            Track trackOne = (Track) PropertyUtils.getIndexedProperty(record, "tracks[0]");
            Track trackThree = (Track) PropertyUtils.getIndexedProperty(record, "tracks[2]");

            System.out.println("trackOne.getTitle() = " + trackOne.getTitle());
            System.out.println("trackThree.getTitle() = " + trackThree.getTitle());
        } catch (Exception e) {
            e.printStackTrace();
        }
    }
}

package org.kodejava.commons.beanutils.support;

import java.util.ArrayList;
import java.util.List;

public class Record {
    private Long id;
    private String title;
    private List<Track> tracks = new ArrayList<>();

    public Long getId() {
        return id;
    }

    public void setId(Long id) {
        this.id = id;
    }

    public String getTitle() {
        return title;
    }

    public void setTitle(String title) {
        this.title = title;
    }

    public List<Track> getTracks() {
        return tracks;
    }

    public void setTracks(List<Track> tracks) {
        this.tracks = tracks;
    }
}

Our program results are:

trackOne.getTitle() = Sgt. Pepper's Lonely Hearts Club Band
trackThree.getTitle() = Lucy In The Sky With Diamonds

Maven Dependencies

<dependency>
    <groupId>commons-beanutils</groupId>
    <artifactId>commons-beanutils</artifactId>
    <version>1.9.4</version>
</dependency>

In this example you’ll see how to read bean’s nested property, we’ll use PropertyUtils.getNestedProperty() method. To test we will create three classes, Track and Artist for our beans and ReadNestedProperty as a main program to run.

The Track class will contain a property of an Artist object. Using the PropertyUtils.getNestedProperty() method we want to get the artist name that sings the track. This method will first read the artist property from the track object and then read the name property of the artist object.

Reading nested property using PropertyUtils.getNestedProperty() it can read nested level in no limit.

package org.kodejava.commons.beanutils;

import org.apache.commons.beanutils.PropertyUtils;
import org.kodejava.commons.beanutils.support.Artist;
import org.kodejava.commons.beanutils.support.Track;

public class ReadNestedProperty {
    public static void main(String[] args) {
        Track track = new Track();
        track.setId(1L);
        track.setTitle("Lucy In The Sky With Diamonds");
        track.setArtist(new Artist(1L, "The Beatles"));

        try {
            String artistName = (String) PropertyUtils.getNestedProperty(track, "artist.name");
            System.out.println("Artist Name = " + artistName);
        } catch (Exception e) {
            e.printStackTrace();
        }
    }
}

package org.kodejava.commons.beanutils.support;

public class Track {
    private Long id;
    private String title;
    private Integer duration;
    private Artist artist;

    public Long getId() {
        return id;
    }

    public void setId(Long id) {
        this.id = id;
    }

    public String getTitle() {
        return title;
    }

    public void setTitle(String title) {
        this.title = title;
    }

    public Integer getDuration() {
        return duration;
    }

    public void setDuration(Integer duration) {
        this.duration = duration;
    }

    public Artist getArtist() {
        return artist;
    }

    public void setArtist(Artist artist) {
        this.artist = artist;
    }

    @Override
    public String toString() {
        return "Track{" +
                "id=" + id +
                ", title='" + title + '\'' +
                ", duration=" + duration +
                '}';
    }
}

package org.kodejava.commons.beanutils.support;

public class Artist {
    private Long id;
    private String name;

    public Artist() {
    }

    public Artist(Long id, String name) {
        this.id = id;
        this.name = name;
    }

    public Long getId() {
        return id;
    }

    public void setId(Long id) {
        this.id = id;
    }

    public String getName() {
        return name;
    }

    public void setName(String name) {
        this.name = name;
    }
}

Maven Dependencies

<dependency>
    <groupId>commons-beanutils</groupId>
    <artifactId>commons-beanutils</artifactId>
    <version>1.9.4</version>
</dependency>

In this example we will learn how to use PropertyUtils.getSimpleProperty() method to read bean’s property value. To test this method we will create a simple class called Track for our bean. The Track class have some properties such as id, title and duration.

The PropertyUtils.getSimpleProperty() reads our bean property by accessing the bean’s getter method. The method takes two parameters. The first parameter is the bean and the second parameter is the bean’s property name. It returns a java.lang.Object as a result, that means we have to cast it to the desired type.

package org.kodejava.commons.beanutils;

import org.apache.commons.beanutils.PropertyUtils;
import org.kodejava.commons.beanutils.support.Track;

public class ReadBeanProperty {
    public static void main(String[] args) {
        Track track = new Track();
        track.setTitle("Here Comes The Sun");

        try {
            String title = (String) PropertyUtils.getSimpleProperty(track, "title");
            System.out.println("Track title = " + title);
        } catch (Exception e) {
            e.printStackTrace();
        }
    }
}

And here is the Track class.

package org.kodejava.commons.beanutils.support;

public class Track {
    private Long id;
    private String title;
    private Integer duration;

    public Long getId() {
        return id;
    }

    public void setId(Long id) {
        this.id = id;
    }

    public String getTitle() {
        return title;
    }

    public void setTitle(String title) {
        this.title = title;
    }

    public Integer getDuration() {
        return duration;
    }

    public void setDuration(Integer duration) {
        this.duration = duration;
    }

    @Override
    public String toString() {
        return "Track{" +
                "id=" + id +
                ", title='" + title + '\'' +
                ", duration=" + duration +
                '}';
    }
}

Maven Dependencies

<dependency>
    <groupId>commons-beanutils</groupId>
    <artifactId>commons-beanutils</artifactId>
    <version>1.9.4</version>
</dependency>