How do I set property value of a bean?

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>

Maven Central

How do I create JSpinner component with hour value?

This example shows you how to create a JSpinner that allow you to select an hour value. As the spinner model we are using the SpinnerDateModel and set the calendar field to Calendar.HOUR_OF_DAY.

To correctly display the hour value on the spinner we also change the formatter of the spinner’s text field using SimpleDateFormatter class.

package org.kodejava.swing;

import javax.swing.*;
import javax.swing.text.DefaultFormatterFactory;
import javax.swing.text.DateFormatter;
import java.awt.*;
import java.util.Date;
import java.util.Calendar;
import java.text.SimpleDateFormat;

public class JSpinnerHour extends JFrame {
    public JSpinnerHour() {
        initializeUI();
    }

    public static void main(String[] args) {
        SwingUtilities.invokeLater(
                () -> new JSpinnerHour().setVisible(true));
    }

    private void initializeUI() {
        setSize(500, 500);
        setDefaultCloseOperation(WindowConstants.EXIT_ON_CLOSE);
        setLayout(new BorderLayout());

        // The following spinner model will have current date as its
        // value and using hour of day as the calendar field. The start
        // and end comparable has a null values which mean it doesn't
        // have minimum or maximum value.
        SpinnerDateModel model = new SpinnerDateModel(new Date(), null,
                null, Calendar.HOUR_OF_DAY);

        JSpinner spinner = new JSpinner(model);

        // Reformat the display of our spinner to show only the hour
        // and minute information part.
        JFormattedTextField textField =
                ((JSpinner.DefaultEditor) spinner.getEditor()).getTextField();
        DefaultFormatterFactory dff =
                (DefaultFormatterFactory) textField.getFormatterFactory();
        DateFormatter formatter = (DateFormatter) dff.getDefaultFormatter();
        formatter.setFormat(new SimpleDateFormat("hh:mm a"));

        getContentPane().add(spinner, BorderLayout.NORTH);
    }
}

How do I create JSpinner component with date value?

The SpinnerDateModel allow us to display and select date information from the JSpinner component. By default, the initial value of the model will be set to the current date. To change it we can call the setValue method of the JSpinner object.

package org.kodejava.swing;

import javax.swing.*;
import java.awt.*;
import java.util.GregorianCalendar;
import java.util.Calendar;

public class JSpinnerDate extends JFrame {
    public JSpinnerDate() {
        initializeUI();
    }

    public static void main(String[] args) {
        SwingUtilities.invokeLater(
                () -> new JSpinnerDate().setVisible(true));
    }

    private void initializeUI() {
        setSize(500, 500);
        setDefaultCloseOperation(WindowConstants.EXIT_ON_CLOSE);
        setLayout(new BorderLayout());

        // Create a SpinnerDateModel with current date as the initial value.
        SpinnerDateModel model = new SpinnerDateModel();

        // Set the spinner value to October 9, 2021.
        JSpinner spinner = new JSpinner(model);
        Calendar calendar = new GregorianCalendar(2021, Calendar.OCTOBER, 9);
        spinner.setValue(calendar.getTime());

        getContentPane().add(spinner, BorderLayout.NORTH);
    }
}

How do I create a JSpinner with a SpinnerListModel?

This example show you how to create a JSpinner component and pass a SpinnerListModel as the available values of the JSpinner component. The SpinnerListModel can hold a value of collections object and a simple array of object instance.

package org.kodejava.swing;

import javax.swing.*;
import java.awt.*;
import java.awt.event.ActionListener;
import java.awt.event.ActionEvent;

public class JSpinnerCreateDemo extends JFrame {
    public JSpinnerCreateDemo() {
        initializeUI();
    }

    public static void main(String[] args) {
        SwingUtilities.invokeLater(
                () -> new JSpinnerCreateDemo().setVisible(true));
    }

    private void initializeUI() {
        setSize(500, 500);
        setDefaultCloseOperation(WindowConstants.EXIT_ON_CLOSE);
        setLayout(new BorderLayout());

        // Creating an array of color name that we'll use as the
        // source of our SpinnerListMode.
        String[] colors = new String[]{
                "Red", "Orange", "Yellow", "Green", "Blue", "Purple"
        };
        SpinnerListModel model = new SpinnerListModel(colors);

        // Create a JSpinner instance with a spinner model as the value.
        // This JSpinner will allow us to select a colour name when we
        // press the JButton below.
        final JSpinner spinner = new JSpinner(model);
        getContentPane().add(spinner, BorderLayout.NORTH);

        JButton okButton = new JButton("OK");
        okButton.addActionListener(e -> {
            String color = (String) spinner.getValue();
            System.out.println("Color = " + color);
        });
        getContentPane().add(okButton, BorderLayout.SOUTH);
    }
}

How do I create a JSpinner component?

JSpinner is a single line input field with two buttons (arrow up and arrow down) that allow us to select a value like number or object from a sequence value. It looks like a combobox without a drop-down.

In the following example we create the default JSpinner that will give us a spinner to select an integer value from it.

package org.kodejava.swing;

import javax.swing.*;
import java.awt.*;

public class JSpinnerCreate extends JFrame {
    public JSpinnerCreate() {
        initialize();
    }

    public static void main(String[] args) {
        SwingUtilities.invokeLater(
                () -> new JSpinnerCreate().setVisible(true));
    }

    private void initialize() {
        setSize(500, 500);
        setDefaultCloseOperation(WindowConstants.EXIT_ON_CLOSE);
        setLayout(new BorderLayout());

        // Create an instance of JSpinner and put it at the top of the frame.
        final JSpinner spinner = new JSpinner();
        getContentPane().add(spinner, BorderLayout.NORTH);

        // Create a JButton and print out the value of the JSpinner when
        // the button is clicked.
        JButton okButton = new JButton("OK");
        okButton.addActionListener(e -> {
            Integer value = (Integer) spinner.getValue();
            System.out.println("value = " + value);
        });
        getContentPane().add(okButton, BorderLayout.SOUTH);
    }
}

How do I get mixed content of an XML element in JDOM?

The following example demonstrates how to read mixed content of an xml element. A mixed content can have more than one type of content such as text (Text), comment (Comment), CDATA (CDATA) or some child elements (Element).

You also see that we can remove the mixed content from the element by calling the remove method of the List just like what we do with a collection of data.

package org.kodejava.jdom;

import org.jdom2.*;
import org.jdom2.input.SAXBuilder;

import java.io.IOException;
import java.io.StringReader;
import java.util.List;

public class JDOMMixedContent {
    public static void main(String[] args) {
        String xml = """
                <root> \
                    <data> \
                        <!-- This element contains application data --> \
                        User Information \
                        <![CDATA[<table><tr><td>-data-</td></tr></table>]]> \
                        <field name="username">alice</field> \
                    </data> \
                </root>""";

        SAXBuilder builder = new SAXBuilder();
        try {
            Document document = builder.build(new StringReader(xml));
            Element root = document.getRootElement();
            Element data = root.getChild("data");

            // Reading the mixed content of an xml element and iterate
            // the result list. This list object can contain any of the
            // following objects: Comment, Element, CDATA, DocType,
            // ProcessingInstruction, EntityRef and Text.
            List<Content> contents = data.getContent();

            for (Content content : contents) {
                if (content instanceof Comment comment) {
                    System.out.println("Comment   = " + comment);
                } else if (content instanceof Element element) {
                    System.out.println("Element   = " + element);
                } else if (content instanceof CDATA cdata) {
                    System.out.println("CDATA     = " + cdata);
                } else if (content instanceof DocType docType) {
                    System.out.println("DocType   = " + docType);
                } else if (content instanceof ProcessingInstruction pi) {
                    System.out.println("PI        = " + pi);
                } else if (content instanceof EntityRef entityRef) {
                    System.out.println("EntityRef = " + entityRef);
                } else if (content instanceof Text text) {
                    System.out.println("Text      = " + text);
                }
            }

            // Remove the second mixed contents which is the CDATA contents.
            contents.remove(2);
        } catch (JDOMException | IOException e) {
            e.printStackTrace();
        }
    }
}

Here are the result of our program:

Text      = [Text:          ]
Comment   = [Comment: <!-- This element contains application data -->]
Text      = [Text:          User Information         ]
CDATA     = [CDATA: <table><tr><td>-data-</td></tr></table>]
Text      = [Text:          ]
Element   = [Element: <field/>]
Text      = [Text:      ]

Maven Dependencies

<dependency>
    <groupId>org.jdom</groupId>
    <artifactId>jdom2</artifactId>
    <version>2.0.6.1</version>
</dependency>

Maven Central

How do I build XML CDATA sections in JDOM?

This example demonstrates how to add CDATA section into an xml document. A CDATA section indicates a block that shouldn’t be parsed. To build a CDATA section just wrap the string with a CDATA object.

package org.kodejava.jdom;

import org.jdom2.CDATA;
import org.jdom2.Document;
import org.jdom2.Element;
import org.jdom2.JDOMException;
import org.jdom2.input.SAXBuilder;
import org.jdom2.output.Format;
import org.jdom2.output.XMLOutputter;

import java.io.IOException;
import java.io.StringReader;

public class JDOMBuildCDATASection {
    public static void main(String[] args) {
        String xml = """
                <root>
                   <comments>
                       <comment></comment>
                   </comments>
                </root>""";

        SAXBuilder builder = new SAXBuilder();
        try {
            Document document = builder.build(new StringReader(xml));
            Element root = document.getRootElement();
            Element comments = root.getChild("comments");

            Element comment = comments.getChild("comment");

            // Using the setContent and addContent to add CDATA section
            // into  the xml element.
            comment.setContent(
                    new CDATA("<b>This is a bold string</b>."));
            comment.addContent(
                    new CDATA("<i>And this an italic string</i>."));

            XMLOutputter outputter =
                    new XMLOutputter(Format.getPrettyFormat());
            outputter.output(document, System.out);

            // Reading a CDATA section is simply done by calling the 
            // getText method. It doesn't care if it was a simple string
            // or a CDATA section, it will just return the content as 
            // string.
            String text = comment.getText();
            System.out.println("Text = " + text);
        } catch (JDOMException | IOException e) {
            e.printStackTrace();
        }
    }
}

The output of the code snippet above:

<?xml version="1.0" encoding="UTF-8"?>
<root>
  <comments>
    <comment><![CDATA[<b>This is a bold string</b>.]]><![CDATA[<i>And this an italic string</i>.]]></comment>
  </comments>
</root>
Text = <b>This is a bold string</b>.<i>And this an italic string</i>.

Maven Dependencies

<dependency>
    <groupId>org.jdom</groupId>
    <artifactId>jdom2</artifactId>
    <version>2.0.6.1</version>
</dependency>

Maven Central

How do I set XML element’s text content in JDOM?

This example show you how so set text content of XML element. Using JDOM we can easily insert text such as HTML tags without worrying about escaping the tags. JDOM will automatically do this conversion.

package org.kodejava.jdom;

import org.jdom2.Document;
import org.jdom2.Element;
import org.jdom2.JDOMException;
import org.jdom2.input.SAXBuilder;
import org.jdom2.output.Format;
import org.jdom2.output.XMLOutputter;

import java.io.IOException;
import java.io.StringReader;

public class JDOMSetTextContent {
    public static void main(String[] args) {
        String xml = """
                <root>
                    <description>
                    </description>
                </root>""";

        SAXBuilder builder = new SAXBuilder();
        try {
            Document document = builder.build(new StringReader(xml));

            Element root = document.getRootElement();
            Element description = root.getChild("description");

            // Adding a text content to the description element. The string
            // will be escaped automatically, so we don't have to use the 
            // < and > symbol.
            description.setText("This is an <strong>IMPORTANT</strong> " +
                    "description");

            XMLOutputter outputter = new XMLOutputter(Format.getPrettyFormat());
            outputter.output(document, System.out);
        } catch (JDOMException | IOException e) {
            e.printStackTrace();
        }
    }
}

Maven Dependencies

<dependency>
    <groupId>org.jdom</groupId>
    <artifactId>jdom2</artifactId>
    <version>2.0.6.1</version>
</dependency>

Maven Central

How do I get XML element’s text content in JDOM?

package org.kodejava.jdom;

import org.jdom2.Document;
import org.jdom2.Element;
import org.jdom2.JDOMException;
import org.jdom2.input.SAXBuilder;

import java.io.IOException;
import java.io.StringReader;

public class JDOMElementTextContent {
    public static void main(String[] args) {
        String xml = """
                <root>
                    <paragraph>
                Lorem ipsum dolor sit amet, consectetur adipisicing \
                elit, sed do eiusmod tempor incididunt ut labore et \
                dolore magna aliqua. Ut enim ad minim veniam, quis \
                nostrud exercitation ullamco laboris nisi ut aliquip \
                ex ea commodo consequat. Duis aute irure dolor in \
                reprehenderit in voluptate velit esse cillum dolore \
                eu fugiat nulla pariatur. Excepteur sint occaecat \
                cupidatat non proident, sunt in culpa qui officia \
                deserunt mollit anim id est laborum.
                    </paragraph>
                </root>""";

        SAXBuilder builder = new SAXBuilder();
        try {
            Document document = builder.build(new StringReader(xml));

            Element root = document.getRootElement();
            Element paragraph = root.getChild("paragraph");

            // Returns the textual content directly held under this element as 
            // a string. This includes all text within this single element, 
            // including whitespace and CDATA sections if they exist.
            String content = paragraph.getText();
            System.out.println("content = " + content);

            // Returns the textual content of this element with all surrounding
            // whitespace removed. If no textual value exists for the element,
            // or if only whitespace exists, the empty string is returned.
            String contentTrimmed = paragraph.getTextTrim();
            System.out.println("contentTrimmed = " + contentTrimmed);

            // Returns the textual content of this element with all surrounding
            // whitespace removed and internal whitespace normalized to a single
            // space. If no textual value exists for the element, or if only
            // whitespace exists, the empty string is returned.
            String contentNormalize = paragraph.getTextNormalize();
            System.out.println("contentNormalize = " + contentNormalize);
        } catch (JDOMException | IOException e) {
            e.printStackTrace();
        }
    }
}

Maven Dependencies

<dependency>
    <groupId>org.jdom</groupId>
    <artifactId>jdom2</artifactId>
    <version>2.0.6.1</version>
</dependency>

Maven Central

How do I get XML attribute as an integer value in JDOM?

In this example you can see how we can read xml attribute value as an integer value instead of string. JDOM provides method such as getIntValue(), getLongValue(), getFloatValue(), getDoubleValue() to get numerical values. For boolean value we can use the getBooleanValue() method.

package org.kodejava.jdom;

import org.jdom2.Document;
import org.jdom2.Element;
import org.jdom2.JDOMException;
import org.jdom2.input.SAXBuilder;

import java.io.IOException;
import java.io.StringReader;

public class JDOMIntegerAttributeValue {
    public static void main(String[] args) {
        String xml = """
                <root>
                    <table width="100"/>
                </root>""";

        SAXBuilder builder = new SAXBuilder();
        try {
            Document document = builder.build(new StringReader(xml));

            Element child = document.getRootElement().getChild("table");
            int tableWidth = child.getAttribute("width").getIntValue();
            System.out.println("tableWidth = " + tableWidth);
        } catch (JDOMException | IOException e) {
            e.printStackTrace();
        }
    }
}

Maven Dependencies

<dependency>
    <groupId>org.jdom</groupId>
    <artifactId>jdom2</artifactId>
    <version>2.0.6.1</version>
</dependency>

Maven Central