Java Swing How to - Create JEditorPane vertical alignment

Question

We would like to know how to create JEditorPane vertical alignment.
Answer

import javax.swing.JFrame;
import javax.swing.JTextPane;
import javax.swing.text.AbstractDocument;
import javax.swing.text.BoxView;
import javax.swing.text.ComponentView;
import javax.swing.text.Element;
import javax.swing.text.IconView;
import javax.swing.text.LabelView;
import javax.swing.text.ParagraphView;
import javax.swing.text.SimpleAttributeSet;
import javax.swing.text.StyleConstants;
import javax.swing.text.StyledDocument;
import javax.swing.text.StyledEditorKit;
import javax.swing.text.View;
import javax.swing.text.ViewFactory;
//  www .  ja  va 2s  .  c o  m
public class Main {
  JTextPane edit = new JTextPane();

  public Main() throws Exception {
    JFrame frame = new JFrame();
    frame.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
    frame.getContentPane().add(edit);
    edit.setEditorKit(new MyEditorKit());
    SimpleAttributeSet attrs = new SimpleAttributeSet();
    StyleConstants.setAlignment(attrs, StyleConstants.ALIGN_CENTER);
    StyledDocument doc = (StyledDocument) edit.getDocument();
    doc.insertString(0, "111\n2222222\n3333", attrs);
    doc.setParagraphAttributes(0, doc.getLength() - 1, attrs, false);

    frame.setSize(300, 300);
    frame.setVisible(true);
  }
  public static void main(String[] args) throws Exception {
    new Main();
  }
}

class MyEditorKit extends StyledEditorKit {

  public ViewFactory getViewFactory() {
    return new StyledViewFactory();
  }

  static class StyledViewFactory implements ViewFactory {

    public View create(Element elem) {
      String kind = elem.getName();
      if (kind != null) {
        if (kind.equals(AbstractDocument.ContentElementName)) {

          return new LabelView(elem);
        } else if (kind.equals(AbstractDocument.ParagraphElementName)) {
          return new ParagraphView(elem);
        } else if (kind.equals(AbstractDocument.SectionElementName)) {

          return new CenteredBoxView(elem, View.Y_AXIS);
        } else if (kind.equals(StyleConstants.ComponentElementName)) {
          return new ComponentView(elem);
        } else if (kind.equals(StyleConstants.IconElementName)) {

          return new IconView(elem);
        }
      }

      return new LabelView(elem);
    }

  }
}

class CenteredBoxView extends BoxView {
  public CenteredBoxView(Element elem, int axis) {

    super(elem, axis);
  }

  protected void layoutMajorAxis(int targetSpan, int axis, int[] offsets,
      int[] spans) {

    super.layoutMajorAxis(targetSpan, axis, offsets, spans);
    int textBlockHeight = 0;
    int offset = 0;

    for (int i = 0; i < spans.length; i++) {
      textBlockHeight += spans[i];
    }
    offset = (targetSpan - textBlockHeight) / 2;
    for (int i = 0; i < offsets.length; i++) {
      offsets[i] += offset;
    }

  }
}