java 远程文件url 转为输入流

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我们在开发过程中经常遇到操作文件的情况，今天记录下。 java 远程文件url 转为输入流，分三步操作： 1.第一步

URL url = new URL(fileUrl);
HttpURLConnection conn = (HttpURLConnection)url.openConnection();
//设置超时间为3秒
conn.setConnectTimeout(3*1000);
//防止屏蔽程序抓取而返回403错误
conn.setRequestProperty("User-Agent", "Mozilla/4.0 (compatible; MSIE 5.0; Windows NT; DigExt)");
//得到输入流
InputStream inputStream = conn.getInputStream();`

```
2.第二步 
```public static AjaxModel parseExcelForInfo(InputStream inputStream, String fileName, int taskId) {
    try {
        //创建workbook对象
        Workbook workbook = null;
        if (fileName.contains(".xlsx")) {
            workbook = new XSSFWorkbook(inputStream);
        } else if (fileName.contains(".xls")) {
            workbook = new HSSFWorkbook(inputStream);
        } else {
            return AjaxModel.failed(-1, "文件类型不正确");
        }
        //获取第一个sheet表
        Sheet sheetAt = workbook.getSheetAt(0);
        if (sheetAt != null) {
            // TODO 校验excel头
            Row headRow = sheetAt.getRow(0);
            for (int i = 0; i < BusinessSettlementConstants.TEMPLATE_COULMN.length; i++) {
                if (!FileUtil.getCellFormatValue(headRow.getCell(i)).trim().equals(BusinessSettlementConstants.TEMPLATE_COULMN[i])) {
                    LOGGER.info("parseExcelForInfo excel头部信息顺序不正确，getCellFormatValue(headRow.getCell(i)):{}," +
                                    "BusinessSettlementConstants.TEMPLATE_COULMN[i]:{},taskId:{}", FileUtil.getCellFormatValue(headRow.getCell(i)),
                            BusinessSettlementConstants.TEMPLATE_COULMN[i], taskId);
                    return AjaxModel.failed("excel标题头顺序不正确:" + FileUtil.getCellFormatValue(headRow.getCell(i)));
                }
            }
            int startRowNum = sheetAt.getFirstRowNum() + 1;
            int lastRowNum = sheetAt.getLastRowNum();

            LOGGER.info("解析excel开始taskId:{}，从【{}】行开始,到第【{}】行结束", taskId, startRowNum, lastRowNum);
            List<Map<String, String>> dataList = new ArrayList<Map<String, String>>();
            for (int rowNum = startRowNum; rowNum <= lastRowNum; rowNum++) {
                // 每一行数据
                Row row = sheetAt.getRow(rowNum);
                Map<String, String> map = new HashMap<>();
                LOGGER.info("parseExcelForInfo row:{}", row);
                if (row != null && row.getCell(0) != null && StringUtils.isNotEmpty(row.getCell(0).getStringCellValue()) && row.getCell(2) != null && row.getCell(4) != null) {
                    LOGGER.info("parseExcelForInfo row:{},cell:{}", row, row.getCell(0));
                    // 姓名
                    map.put("userName", FileUtil.getCellFormatValue(row.getCell(0)));
                    
                    dataList.add(map);
                }
            }
            LOGGER.info("--------------解析完成 dataList:{}", dataList);
            if (dataList.size() <= 0) {
                return AjaxModel.failed(-1, "解析表格数据为空");
            }
            AjaxModel success = AjaxModel.success();
            success.getData().put("dataList", dataList);
            return success;
        } else {
            LOGGER.info("sheet内容为空");
            return AjaxModel.failed(-1, "表格内容为空");
        }
    } catch (Exception e) {
        LOGGER.error("parseExcelForInfo 解析异常", e);
    }
    return AjaxModel.failed(-1, "解析表格异常");
}
```

3.第二步

```public static String getCellFormatValue(Cell cell) {
    cell.setCellType(CellType.STRING);
    return cell.getStringCellValue();
}
```