处理excel将下标转换为ABCD列

/**
     * 处理excel将下标转换为ABCD列，将下标转换为字母，调用该方法时必须+1；例：String columnNumber = getIndexWord(0+1);columnNumber=A;
     * @Title: getIndexWord 
     * @author hegg
     * @date 2020年1月1日 下午8:59:14
     * @return 返回类型 String 
     * @param
     */
    public static String getIndexWord(Integer i){
        String[] word = new String[]{"A","B","C","D","E","F","G","H","I","J","K","L","M","N","O","P","Q","R","S","T","U","V","W","X","Y","Z"};
        int d = i/26;
        int x = i%26;
        String w = "";
        if(x == 0){
            if(d>1){
                w= word[d-2] + "" + word[25];
            } else {
                w = word[i-1];
            }
        } else {
            if(d>=1){
                w= word[d-1] + "" + word[x-1];
            } else {
                w = word[x-1];
            }
        }
        
        Map<Integer, String> a = new LinkedHashMap<Integer, String>();
        a.put(i, w);
        return a.get(i);
    }