This example demonstrate how to use PropertyUtils.setMappedProperty() method to modify a Map typed property value of a bean. To set the property we need to pass bean instance, property name, map key and map value to PropertyUtils.setMappedProperty() method.

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.HashMap;
import java.util.Map;

public class PropertySetMappedExample {

    public static void main(String[] args) {
        // Create an instance of Recording bean.
        Record record = new Record();
        record.setId(1L);
        record.setTitle("Introduction");

        // Create a map to hold record tracks.
        Map<String, Track> tracks = new HashMap<>();
        tracks.put("track-one", new Track());
        tracks.put("track-two", new Track());
        tracks.put("track-three", new Track());
        record.setMapTracks(tracks);

        try {
            // We add another tracks to the record track using
            // a PropertyUtils.setMappedProperty() method.
            PropertyUtils.setMappedProperty(record,
                    "mapTracks", "track-four", new Track());
            PropertyUtils.setMappedProperty(record,
                    "mapTracks", "track-five", new Track());
        } catch (Exception e) {
            e.printStackTrace();
        }

        tracks = record.getMapTracks();
        System.out.println("New Track Numbers: " + tracks.size());
        for (String key : tracks.keySet()) {
            System.out.println(key + " = " + tracks.get(key));
        }
    }
}

Maven Dependencies

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

In this example we show how to set the value of an indexed property. In the code below we modified the value of an array type. We’ll change the second colors of MyBean‘s colors property.

We do it in the same way as we are using the PropertyUtils.setSimpleProperty method. For indexed property we use the PropertyUtils.setIndexedProperty method and passes four arguments, they are the instance of bean to be manipulated, the indexed property name, the index to be changes and finally the new value.

package org.kodejava.commons.beanutils;

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

import java.util.Arrays;

public class PropertySetIndexedExample {
    public static void main(String[] args) {
        String[] colors = new String[]{"red", "green", "blue"};

        MyBean myBean = new MyBean();
        myBean.setColors(colors);
        System.out.println("Colors = " + Arrays.toString(myBean.getColors()));

        try {
            PropertyUtils.setIndexedProperty(myBean, "colors", 1, "orange");
        } catch (Exception e) {
            e.printStackTrace();
        }

        System.out.println("Colors = " + Arrays.toString(myBean.getColors()));
    }
}

package org.kodejava.commons.beanutils.support;

public class MyBean {
    private String[] colors;

    public void setColors(String[] colors) {
        this.colors = colors;
    }

    public String[] getColors() {
        return colors;
    }
}

The output of this code is:

Colors = [red, green, blue]
Colors = [red, orange, blue]

Maven Dependencies

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

The Commons BeanUtils component provides a class called PropertyUtils that supplies method for manipulating a bean such as our Track class below. For this demo we use a Track class that have a property called id, title and duration.

To set the value of a bean we can use the PropertyUtils.setProperty() method. This method ask for the bean instance whose property value to be set, the property name and the value.

package org.kodejava.commons.beanutils;

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

public class PropertySetExample {
    public static void main(String[] args) {
        Track track = new Track();
        try {
            PropertyUtils.setProperty(track, "id", 10L);
            PropertyUtils.setProperty(track, "title", "Hey Jude");
            PropertyUtils.setProperty(track, "duration", 180);
        } catch (Exception e) {
            e.printStackTrace();
        }

        System.out.println("Track = " + track);
    }
}

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 +
                '}';
    }
}

Some exceptions could be thrown by this method, so we need to handle the IllegalAccessException, InvocationAccessException and NoSuchMethodException. To make the code simple we will just catch it as java.lang.Exception.

These exceptions could happen if we don’t have access to the property, or the bean’s accessor throws an exception or if the method we tried to manipulate doesn’t exist.

Maven Dependencies

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

Using the PropertyUtils.getPropertyType() we can determine the bean property type. This method return a Class object of bean’s property type.

package org.kodejava.commons.beanutils;

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

public class PropertyType {
    public static void main(String[] args) {
        Record record = new Record();
        record.setTitle("Magical Mystery Tour");

        try {
            /*
             * Using PropertyUtils.getPropertyType() to determine the type of
             * title property.
             */
            Class<?> type = PropertyUtils.getPropertyType(record, "title");
            System.out.println("type = " + type.getName());

            String value = (String) PropertyUtils.getProperty(record, "title");
            System.out.println("value = " + value);
        } catch (Exception e) {
            e.printStackTrace();
        }
    }
}

package org.kodejava.commons.beanutils.support;

import java.util.ArrayList;
import java.util.HashMap;
import java.util.List;
import java.util.Map;

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

    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;
    }

    public void setMapTracks(Map<String, Track> mapTracks) {
        this.mapTracks = mapTracks;
    }

    public Map<String, Track> getMapTracks() {
        return mapTracks;
    }
}

The output of the code snippet above:

type = java.lang.String
value = Magical Mystery Tour

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 mapped property value of a bean. We use PropertyUtils.getMappedProperty() method the read the mapped property of the Record object that consist of Track objects.

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.HashMap;
import java.util.Map;

public class ReadMapProperty {
    public static void main(String[] args) {
        Record record = new Record();
        record.setTitle("Abbey Road");

        Track track1 = new Track();
        track1.setTitle("Come Together");

        Track track2 = new Track();
        track2.setTitle("Something");

        Map<String, Track> tracks = new HashMap<>();
        tracks.put("1", track1);
        tracks.put("2", track2);

        record.setMapTracks(tracks);

        try {
            Track track = (Track) PropertyUtils.getMappedProperty(record, "mapTracks(1)");
            System.out.println("track.getTitle() = " + track.getTitle());
        } catch (Exception e) {
            e.printStackTrace();
        }
    }
}

package org.kodejava.commons.beanutils;

import java.util.ArrayList;
import java.util.HashMap;
import java.util.List;
import java.util.Map;

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

    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;
    }

    public void setMapTracks(Map<String, Track> mapTracks) {
        this.mapTracks = mapTracks;
    }

    public Map<String, Track> getMapTracks() {
        return mapTracks;
    }
}

And here is the result of our program.

track.getTitle() = Come Together

Maven Dependencies

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