Read the Excel value using JSF - jsf

Question

I need to read an Excel file and display its content.
I have a backing bean code which reads a particular Excel file and displays its content in the console. I have to display the contents inside a text editor. Using PrimeFaces I have got the <p:fileUpload> and <p:editor>.
Here's the bean:
public void handleFileUpload(FileUploadEvent event) {
FacesMessage msg = new FacesMessage("Succesful", event.getFile().getFileName() + " is uploaded.");
FacesContext.getCurrentInstance().addMessage(null, msg);
}
public String convertjava(String b) {
try
{
FileInputStream file = new FileInputStream(new File(""));
// Get the workbook instance for XLS file
HSSFWorkbook workbook = new HSSFWorkbook(file);
// Get first sheet from the workbook
HSSFSheet sheet = workbook.getSheetAt(0);
// Iterate through each rows from first sheet
Iterator<Row> rowIterator = sheet.rowIterator();
while (rowIterator.hasNext()) {
Row row = rowIterator.next();
// For each row, iterate through each columns
Iterator<Cell> cellIterator = row.cellIterator();
while (cellIterator.hasNext()) {
Cell cell = cellIterator.next();
switch (cell.getCellType()) {
case Cell.CELL_TYPE_BOOLEAN:
cell.getBooleanCellValue();
break;
case Cell.CELL_TYPE_NUMERIC:
cell.getNumericCellValue();
break;
case Cell.CELL_TYPE_STRING:
cell.getStringCellValue();
break;
}
}
System.out.println("");
}
file.close();
FileOutputStream out = new FileOutputStream(new File(""));
workbook.write(out);
out.close();
} catch (FileNotFoundException e) {
e.printStackTrace();
} catch (IOException e) {
System.out.println("error");
}
}
Here's the Facelet:
<h:body>
<h:form enctype="multipart/form-data">
<p:fileUpload fileUploadListener="#{uploadBean.handleFileUpload}"
mode="advanced" update="display" auto="true" sizeLimit="10000000"
allowTypes="/(\.|\/)(xls|xlsx)$/" />
<p:growl id="display" showDetail="true" />
<h:commandButton action="#{uploadBean.convertjava}"
value="Excel Report" />
</h:form>
<br />
</h:body>
Here I am totally blank that how to call that convertJava() method through JSF tags and display the read excel values inside an text editor.

Answer 1

You should get hold of the uploaded file in the file upload listener method. You are currently nowhere doing that. You're basically completely ignoring the uploaded file. This makes indeed no sense.
Assign it as a property of the (view scoped) bean as follows:
private UploadedFile uploadedFile;
public void handleFileUpload(FileUploadEvent event) {
uploadedFile = event.getFile();
// ...
}
Then just feed its InputStream to HSSFWorkbook constructor. You're currently attempting to read a non-existing file. This makes indeed no sense. You should be reading the uploaded file. Replace the nonsensicial
FileInputStream file = new FileInputStream(new File(""));
HSSFWorkbook workbook = new HSSFWorkbook(file);
// ...
by
InputStream input = uploadedFile.getInputStream();
HSSFWorkbook workbook = new HSSFWorkbook(input);
// ...
By the way, inside the loop over the Excel cells, you're also nowhere assigning the found data to a property/variable. All with all, it seems that your root mistake is that you keep ignoring values provided to you instead of assigning them to variables for later reuse/redisplay. This problem is in turn not exactly related to JSF, but just to basic Java. Therefore I recommend to take a JSF pause and make an effort of learning basic Java.