方法 将ids按数量分组放入List集合

当ids数量成千上万的时候，如果还要使用in方法进行查询，ids可以先分组得到idList再循环idList查询；

code：

   /**
     * 将id串分隔成若干份
     * @param vids
     * @param len
     * @return
     */
    public static List<String> splitSqlParamsToList(String ids, int len){
        List<String> vidList = new ArrayList<>();
        StringBuffer buffer = new StringBuffer();
        String[] split = ids.split(",");
        int length = split.length;
        // 分隔vids串，单个大小len长度
        String value = "";
        for (int i = 0; i < length; i++) {
            value = split[i];
            if(isNullOrEmpty(value)){
                continue;
            }
            // (i + 1) % len != 0
            if(isNullOrEmpty(buffer.toString())){
                buffer.append(value);
            }else{
                buffer.append("," + value);
            }
            if(buffer.toString().split(",").length % len != 0){
                if(i != (length - 1)){
                    // 不是最后一位
                    continue;
                }
            }
            vidList.add(buffer.toString());
            buffer = new StringBuffer();
        }
        return vidList;
    }

code2（重写）：

    /**
     * 将list分割后拼接成字符串
     * @param list
     * @param separator
     * @return
     */
    public static String listToString(List<String> list, String separator) {
        StringBuilder builder = new StringBuilder();
        if(!CollectionUtils.isEmpty(list)){
            for (String val : list) {
                if(builder.length() > 0){
                    builder.append(separator);
                }
                builder.append(val);
            }
        }
        return builder.toString();
    }
    
    /**
     * 将id串分隔成若干份（重写）
     * @param ids
     * @param len
     * @return
     */
    public static List<String> splitSqlParamsToList(String ids, int len){
        // 将id串分组
        List<String> list = new ArrayList<>();
        
        String[] idArr = ids.split(",");
        List<String> idList = new ArrayList<>();
        for (int i = 0; i < idArr.length; i++) {
            if(idArr[i] != null && !"".equals(idArr[i])){
                idList.add(idArr[i]);
            }
        }
        System.out.println(idList);
        
        int size = idList.size();
        System.out.println(size);
        int lastIndex = size - 1;
        int fromIndex = 0;
        int toIndex;
        boolean flag = false;
        do {
            toIndex = fromIndex + len;
            List<String> child;
            if (toIndex >= lastIndex) {// 最后一组
                child = idList.subList(fromIndex, size);
                System.out.println("开始：" + (fromIndex + 1) + "，结束：" + size + "。" + child);
                list.add(listToString(child, ","));
                break;
            }
            child = idList.subList(fromIndex, toIndex);
            System.out.println("开始：" + (fromIndex + 1) + "，结束：" + toIndex + "。" + child);
            list.add(listToString(child, ","));
            fromIndex += len;
            
            flag = fromIndex <= lastIndex;
            
        } while (flag);
        return list;
    }

test：

String vids = "1,2,3,4,5,6,7,8,,22,,11,,,10,12";
List<String> list = splitSqlParamsToList(vids, 6);
for (int i = 0; i < list.size(); i++) {
    System.out.println("第" + i + "组：" + list.get(i));
}

result：

第0组：1,2,3,4,5,6
第1组：7,8,22,11,10,12