docs: @Override
      public String updateItemValue(Long configId, String value) {
  
          Config config = getConfigById(configId);
          String oldValue = config.getValue();
  
          //
          // 配置数据库的值 encode to db
          //
          configDao.updateValue(configId, CodeUtils.utf8ToUnicode(value));
          configHistoryMgr.createOne(configId, oldValue, CodeUtils.utf8ToUnicode(value));
  
          //
          // 发送邮件通知
          //
          String toEmails = appMgr.getEmails(config.getAppId());
  
          if (applicationPropertyConfig.isEmailMonitorOn()) {
              boolean isSendSuccess = logMailBean.sendHtmlEmail(toEmails,
                      " config update", DiffUtils.getDiff(CodeUtils.unicodeToUtf8(oldValue),
                              value,
                              config.toString(),
                              getConfigUrlHtml(config)));
              if (isSendSuccess) {
                  return "修改成功，邮件通知成功";
              } else {
                  return "修改成功，邮件发送失败，请检查邮箱配置";
              }
          }
  
          return "修改成功";
      }