/**
     * 方法的重载
     * d逗号分割工具类
     * @param list  List<String>
     * @return
     */
    public static String stringJoins(List<String> list){
        return stringJoins(list,",");
    }

    /**
     *
     * @param list List<String>
     * @param split 分割符号 传过来什么符号就是什么符号
     * @return
     */
    public static String stringJoins(List<String> list,String split){
        if(list==null||list.size()==0){
            return null;
        }
        StringBuilder builder = new StringBuilder();
        for (int i = 0; i < list.size(); i++) {
            if(i!=0){
                builder.append(split);
            }
            builder.append(list.get(i));
        }
        return builder.toString();
    }