code: public static Alert getAlert(String title, String header, String content, AlertType alertType) {
          return getAlert(title, header, content, alertType, Modality.APPLICATION_MODAL, null, StageStyle.DECORATED);
      }
docs: 获取{@link Alert}对象，modality默认为{@link Modality#APPLICATION_MODAL}，window默认为null，style默认为{@link
  StageStyle#DECORATED}
  
  @param title 标题
  @param header 信息头
  @param content 内容
  @param alertType {@link AlertType}
  
  @return {@link Alert}