java 如何从java中的Workbook对象获取inputStream
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how to get the inputStream from Workbook object in java
提问by aradhya
When I upload the file i am passing the inputstream to the workbook. Now I want to use this InputStreamfrom workbook in another method like save where I save the file InputStreamin to DB. Here is my code.
当我上传文件时，我将输入流传递给工作簿。现在我想InputStream在另一种方法中使用工作簿中的这个，比如保存我将文件保存InputStream到数据库的位置。这是我的代码。
public void FileUpload(FileUploadEvent event) throws ParseException {
UploadedFile item = event.getUploadedFile();
Workbook workbook = org.apache.poi.ss.usermodel.WorkbookFactory.create(item.getInputStream());
}
Now I want to make Workbook object as instance variable and pass to another method like below.
现在我想将 Workbook 对象作为实例变量并传递给另一个方法，如下所示。
public String save() throws SQLException, IOException{
fileId = dao.savefile(workbook,fileName);
}
In my savefile method
在我的保存文件方法中
InputStream inptest= **workbook.getStream**
ps.setBinaryStream(2,fin,fin.available());
So inptestvariable accepts InputStreamwhich I wanted to get it from Workbook.
所以inptest变量接受InputStream我想从工作簿中获取它。
回答by GreenGiant
It sounds like what you are asking for is a way to use the InputStream for multiple purposes:
听起来您要求的是一种将 InputStream 用于多种目的的方法：
- To create a Workbook object (which you're already doing)
- To save the content of that InputStream somewhere else
- 创建一个 Workbook 对象（您已经在做）
- 将该 InputStream 的内容保存在其他地方
Since reading from an InputStream is usually a one-time-only operation that cannot be repeated, then you can do the following:
由于从 InputStream 读取通常是不能重复的一次性操作，因此您可以执行以下操作：
- Save the full content of the InputStream to a buffer.
- Open two new InputStreams from the buffer.
- Pass your InputStreams to your two methods.
- 将 InputStream 的全部内容保存到缓冲区。
- 从缓冲区打开两个新的 InputStreams。
- 将您的 InputStreams 传递给您的两个方法。
Code might look like this:
代码可能如下所示：
public void FileUpload(FileUploadEvent event) throws ParseException {
UploadedFile item = event.getUploadedFile();
InputStream originalInputStream = item.getInputStream();
byte[] buffer = IOUtils.toByteArray(originalInputStream);
InputStream is1 = new ByteArrayInputStream(buffer);
InputStream is2 = new ByteArrayInputStream(buffer);
Workbook workbook = org.apache.poi.ss.usermodel.WorkbookFactory.create(is1);
}
InputStream inptest = is2;
ps.setBinaryStream(2,fin,fin.available());
Note: this uses Apache Commons IO libraryfor IOUtils.
注意：这使用IOUtils 的Apache Commons IO 库。
回答by csunday95
If you are trying to save the Workbook object to a file, there is a method write()which takes in an OutputStream. Saving to a file can then be accomplished by
如果您尝试将 Workbook 对象保存到文件中，则有一个方法write()接受一个 OutputStream。然后可以通过以下方式保存到文件
FileOutputStream fos = new FileOutputStream("path/to/file/[filename]");
workbook.write(fos);
fos.close();
