创建 DefaultStyledDocument

try {
    StyledDocument doc = new DefaultStyledDocument();
    doc.insertString(0, "This is the beginning text", null);
    doc.insertString(doc.getLength(), "\nInserting new line at end of doc", null);
    MutableAttributeSet attrs = new SimpleAttributeSet();
    StyleConstants.setBold(attrs, true);
    doc.insertString(5, "This is bold text after 'this'", attrs);
} catch (BadLocationException ex) {
    //handle error
}

DefaultStyledDocuments 可能是你最常用的资源。它们可以直接创建，并且是 StyledDocument 抽象类的子类。