去除java list 中的 [] 括号

private String toString(Collection collection){
        StringBuffer stringbuffer = new StringBuffer();
        Iterator iterator1 = collection.iterator();
        boolean flag = iterator1.hasNext();
        do
        {
            if(!flag)
                break;
            Object obj = iterator1.next();
            stringbuffer.append(obj != this ? String.valueOf(obj) : "(this Collection)");
            flag = iterator1.hasNext();
            if(flag)
                stringbuffer.append(",");
        } while(true);
        return stringbuffer.toString();
    }

StringUtils.strip( "[‘a‘,‘b‘,‘c‘,‘d‘]", "[]");