请参考以下示例代码：

// Add text field			
try {				
Control control = form.addControl(page, "Text Field0", Field.e_TypeTextField, new RectF(50, 600, 90, 640));				DefaultAppearance defaultAppearance = new DefaultAppearance(e_FlagFont|e_FlagFontSize|e_FlagTextColor,new Font(e_StdIDCourier),10,1);				control.getField().setDefaultAppearance(defaultAppearance);				control.getField().setValue("3测试");				// Update text field's appearance.				control.getWidget().resetAppearanceStream();				//这段可注释掉，先执行上面的代码，对比看差异				DefaultAppearance defaultAppearance_New = control.getField().getDefaultAppearance(); //				defaultAppearance_New.setText_size(20);				defaultAppearance_New.setText_color(16711680);				control.getField().setDefaultAppearance(defaultAppearance_New);				control.getField().setValue("new 测试");				control.getWidget().resetAppearanceStream();			} catch (PDFException e) {				e.printStackTrace();			
}			
System.out.println("Add text field.");

您需要注意此样例的处理逻辑，并且注意resetAppearanceStream()方法的调用。