如果你想改变文本窗格中每个字符的样式，这里有一个完全随机的方法。您为每个字符创建不同的属性集。由你来找到合适的组合（前景/背景对比，字符大小差别不大等等）。您还可以存储已经应用的不同样式，这样您就不会使用相同的两种样式。

If you want to change the style for each character in a textpane, here is a complete random way to do it. You create a different attribute set for each character. Up to you to find appropriate combination (foreground/background contrast, not too much difference in size of the chars, etc...). You could also store the different styles you have already applied so that you don't use the same one twice.

import java.awt.Color;
import java.util.Random;

import javax.swing.JFrame;
import javax.swing.JScrollPane;
import javax.swing.JTextPane;
import javax.swing.text.DefaultStyledDocument;
import javax.swing.text.SimpleAttributeSet;
import javax.swing.text.StyleConstants;
import javax.swing.text.StyledDocument;

public class TestDifferentStyles {
    private void initUI() {
        JFrame frame = new JFrame(TestDifferentStyles.class.getSimpleName());
        frame.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);

        StyledDocument doc = new DefaultStyledDocument();
        JTextPane textPane = new JTextPane(doc);
        textPane.setText("Lorem Ipsum is simply dummy text of the printing and typesetting industry. Lorem Ipsum has "
                + "been the industry's standard dummy text ever since the 1500s, when an unknown printer took a galley of "
                + "type and scrambled it to make a type specimen book. It has survived not only five centuries, but also the "
                + "leap into electronic typesetting, remaining essentially unchanged. It was popularised in the 1960s with the"
                + " release of Letraset sheets containing Lorem Ipsum passages, and more recently with desktop publishing "
                + "software like Aldus PageMaker including versions of Lorem Ipsum.");

        Random random = new Random();
        for (int i = 0; i < textPane.getDocument().getLength(); i++) {
            SimpleAttributeSet set = new SimpleAttributeSet();
            // StyleConstants.setBackground(set, new Color(random.nextInt(256), random.nextInt(256), random.nextInt(256)));
            StyleConstants.setForeground(set, new Color(random.nextInt(256), random.nextInt(256), random.nextInt(256)));
            StyleConstants.setFontSize(set, random.nextInt(12) + 12);
            StyleConstants.setBold(set, random.nextBoolean());
            StyleConstants.setItalic(set, random.nextBoolean());
            StyleConstants.setUnderline(set, random.nextBoolean());

            doc.setCharacterAttributes(i, 1, set, true);
        }

        frame.add(new JScrollPane(textPane));
        frame.setSize(500, 400);
        frame.setVisible(true);
    }

    public static void main(String[] args) {

        javax.swing.SwingUtilities.invokeLater(new Runnable() {
            @Override
            public void run() {
                new TestDifferentStyles().initUI();
            }
        });
    }

}