List<SmsMessageGroupView> message = smsMessageGroupService.getSmsMessageGroup(sendMessageParams);

　　//创建map集合
    Map<String, Object> map = new HashMap<String, Object>();
   //创建StringBuilder 
　　StringBuilder phone = new StringBuilder();
　　//对集合进行遍历，实现拼接
    for (int i = 0; i < message.size(); i++) {
        try {
            if ("".equals(message.get(i).getExigencyPhone())) {

            } else {
                if (i == message.size() - 1) {
                    phone.append(message.get(i).getExigencyPhone());
                } else {
                    phone.append(message.get(i).getExigencyPhone());
                    phone.append(",");
                }
            }
        } catch (Exception e) {
            e.printStackTrace();
        } finally {
        }
    }

拼接结果是13489098883,13489098883,13489098883,