I want to create a table in a Microsoft Office Word file using Java. Can anybody tell me how to do it with an example?
Have a look at Apache POI
The POI project is the master project
for developing pure Java ports of file
formats based on Microsoft's OLE 2
Compound Document Format. OLE 2
Compound Document Format is used by
Microsoft Office Documents, as well as
by programs using MFC property sets to
serialize their document objects.
I've never seen it done, and I work in Word a lot. If you really want to programatically do something in a word document then I'd advise using Microsoft's scripting language VBA which is specifically designed for this purpose. In fact, I'm working in it right now.
If you're working under Open Office then they have a very similar set of macro-powered tools for doing the same thing.
Office 2003 has an xml format, and the default document format for office 2007 is xml (zipped). So you could just generate xml from java. If you open an existing document it's not too hard too see the xml required.
Alternatively, you could use openoffice's api to generate a document, and save it as a ms-word document.
This snippet can be used to create a table dynamically in MS Word document.
WPFDocument document = new XWPFDocument();
XWPFTable tableTwo = document.createTable();
XWPFTableRow tableTwoRowOne = tableTwo.getRow(0);
tableTwoRowOne.getCell(0).setText(Knode1);
tableTwoRowOne.createCell().setText(tags.get("node1").toString());
for (int i = 1; i < nodeList.length; i++) {
String node = "node";
String nodeVal = "";
XWPFTableRow tr = null;
node = node + (i + 1);
nodeVal = tags.get(node).toString();
if (tr == null) {
tr = tableTwo.createRow();
tr.getCell(0).setText(nodeList[i]);
tr.getCell(1).setText(tags.get(node).toString());
}
}
Our feature set is to hit a button in our web app and get the page you are looking at back as a Word document. We use the docx schema for description of documents and have a bunch of Java code on the server side which does the document creation and response back to our web client. The formatting itself is done with some compiled xsl-t's from within Java to translate from our own XML persistence tier.
The docx schema is pretty hard to understand. The way we made most progress was to create template docx's in Word with exactly the formatting that we needed but with bogus content. We then fooled around with them until we understood exactly what was going on. There is a huge amount in the docx that you don't really need to worry about. When reading / translating the docx Word is pretty tolerant to a partially complete formatting schema. In fact we chose to strip out pretty much all the formatting because it also means that the user's default formatting takes precedence, which they seem to prefer. It also makes the xsl process faster and the resulting document smaller.
I manage the docx4j project
docx4j contains a class TblFactory, which creates regular tables (ie no row or column spans), with the default settings which Word 2007 would create, and with the dimensions specified by the user.
If you want a more complex table, the easiest approach is to create it in Word, then copy the resulting XML into a String in your IDE, where you can use docx4j's XmlUtils.unmarshalString to create a Tbl object from it.
Using my little zip utility, you can create docx with ease, if you know what you're doing. Word's DOCX file format is simply zip (folders with xml files). By using java zip utilities, you can modify existing docx, just the content part.
For the following sample to work, simply open Word, enter few lines, save document. Then with zip program, remove file word/document.xml (this is file where main content of the Word document is residing) from the zip. Now you have the template prepared. Save modified zip.
Here is what creation of new Word file looks:
/* docx file head */
final String DOCUMENT_XML_HEAD =
"<?xml version=\"1.0\" encoding=\"UTF-8\" standalone=\"yes\" ?>" +
"<w:document xmlns:wpc=\"http://schemas.microsoft.com/office/word/2010/wordprocessingCanvas\" xmlns:mc=\"http://schemas.openxmlformats.org/markup-compatibility/2006\" xmlns:o=\"urn:schemas-microsoft-com:office:office\" xmlns:r=\"http://schemas.openxmlformats.org/officeDocument/2006/relationships\" xmlns:m=\"http://schemas.openxmlformats.org/officeDocument/2006/math\" xmlns:v=\"urn:schemas-microsoft-com:vml\" xmlns:wp14=\"http://schemas.microsoft.com/office/word/2010/wordprocessingDrawing\" xmlns:wp=\"http://schemas.openxmlformats.org/drawingml/2006/wordprocessingDrawing\" xmlns:w10=\"urn:schemas-microsoft-com:office:word\" xmlns:w=\"http://schemas.openxmlformats.org/wordprocessingml/2006/main\" xmlns:w14=\"http://schemas.microsoft.com/office/word/2010/wordml\" xmlns:w15=\"http://schemas.microsoft.com/office/word/2012/wordml\" xmlns:wpg=\"http://schemas.microsoft.com/office/word/2010/wordprocessingGroup\" xmlns:wpi=\"http://schemas.microsoft.com/office/word/2010/wordprocessingInk\" xmlns:wne=\"http://schemas.microsoft.com/office/word/2006/wordml\" xmlns:wps=\"http://schemas.microsoft.com/office/word/2010/wordprocessingShape\" mc:Ignorable=\"w14 w15 wp14\">" +
"<w:body>";
/* docx file foot */
final String DOCUMENT_XML_FOOT =
"</w:body>" +
"</w:document>";
final ZipOutputStream zos = new ZipOutputStream(new FileOutputStream("c:\\TEMP\\test.docx"));
final String fullDocumentXmlContent = DOCUMENT_XML_HEAD + "<w:p><w:r><w:t>Hey MS Word, hello from java.</w:t></w:r></w:p>" + DOCUMENT_XML_FOOT;
final si.gustinmi.DocxZipCreator creator = new si.gustinmi.DocxZipCreator();
// create new docx file
creator.createDocxFromExistingDocx(zos, "c:\\TEMP\\existingDocx.docx", fullDocumentXmlContent);
These are zip utilities:
package si.gustinmi;
import java.io.*;
import java.nio.charset.StandardCharsets;
import java.util.logging.Logger;
import java.util.zip.CRC32;
import java.util.zip.ZipEntry;
import java.util.zip.ZipInputStream;
import java.util.zip.ZipOutputStream;
/**
* Creates new docx from existing one.
* #author gustinmi [at] gmail [dot] com
*/
public class DocxZipCreator {
public static final Logger log = Logger.getLogger(DocxZipCreator.class.getCanonicalName());
private static final int BUFFER_SIZE = 4096;
/** OnTheFly zip creator. Traverses through existing docx zip and creates new one simultaneousl.
* On the end, custom document.xml is inserted inside
* #param zipFilePath location of existing docx template (without word/document.xml)
* #param documentXmlContent content of the word/document.xml
* #throws IOException
*/
public void createDocxFromExistingDocx(ZipOutputStream zos, String zipFilePath, String documentXmlContent) throws IOException {
final FileInputStream fis = new FileInputStream(zipFilePath);
final ZipInputStream zipIn = new ZipInputStream(fis);
try{
log.info("Starting to create new docx zip");
ZipEntry entry = zipIn.getNextEntry();
while (entry != null) { // iterates over entries in the zip file
copyEntryfromZipToZip(zipIn, zos, entry.getName());
zipIn.closeEntry();
entry = zipIn.getNextEntry();
}
// add document.xml to existing zip
addZipEntry(documentXmlContent, zos, "word/document.xml");
}finally{
zipIn.close();
zos.close();
log.info("End of docx creation");
}
}
/** Copies sin gle entry from zip to zip */
public void copyEntryfromZipToZip(ZipInputStream is, ZipOutputStream zos, String entryName)
{
final byte [] data = new byte[BUFFER_SIZE];
int len;
int lenTotal = 0;
try {
final ZipEntry entry = new ZipEntry(entryName);
zos.putNextEntry(entry);
final CRC32 crc32 = new CRC32();
while ((len = is.read(data)) > -1){
zos.write(data, 0, len);
crc32.update(data, 0, len);
lenTotal += len;
}
entry.setSize(lenTotal);
entry.setTime(System.currentTimeMillis());
entry.setCrc(crc32.getValue());
}
catch (IOException ioe){
ioe.printStackTrace();
}
finally{
try { zos.closeEntry();} catch (IOException e) {}
}
}
/** Create new zip entry with content
* #param content content of a new zip entry
* #param zos
* #param entryName name (npr: word/document.xml)
*/
public void addZipEntry(String content, ZipOutputStream zos, String entryName)
{
final byte [] data = new byte[BUFFER_SIZE];
int len;
int lenTotal = 0;
try {
final InputStream is = new ByteArrayInputStream(content.getBytes(StandardCharsets.UTF_8));
final ZipEntry entry = new ZipEntry(entryName);
zos.putNextEntry(entry);
final CRC32 crc32 = new CRC32();
while ((len = is.read(data)) > -1){
zos.write(data, 0, len);
crc32.update(data, 0, len);
lenTotal += len;
}
entry.setSize(lenTotal);
entry.setTime(System.currentTimeMillis());
entry.setCrc(crc32.getValue());
}
catch (IOException ioe){
ioe.printStackTrace();
}
finally{
try { zos.closeEntry();} catch (IOException e) {}
}
}
}
Office Writer would be a better tool to use than POI for your requirement.
If all you want is a simple table without too much of formatting, I would use this simple trick. Use Java to generate the table as HTML using plain old table,tr,td tags and copy the rendered HTML table into the word document ;)
Click here for a Working example with source code.
This example generates MS-Word docs from Java, based on a template concept.
Related
I have this application I'm developing in JSP and I wish to export some data from the database in XLS (MS Excel format).
Is it possible under tomcat to just write a file as if it was a normal Java application, and then generate a link to this file? Or do I need to use a specific API for it?
Will I have permission problems when doing this?
While you can use a full fledged library like JExcelAPI, Excel will also read CSV and plain HTML tables provided you set the response MIME Type to something like "application/vnd.ms-excel".
Depending on how complex the spreadsheet needs to be, CSV or HTML can do the job for you without a 3rd party library.
Don't use plain HTML tables with an application/vnd.ms-excel content type. You're then basically fooling Excel with a wrong content type which would cause failure and/or warnings in the latest Excel versions. It will also messup the original HTML source when you edit and save it in Excel. Just don't do that.
CSV in turn is a standard format which enjoys default support from Excel without any problems and is in fact easy and memory-efficient to generate. Although there are libraries out, you can in fact also easily write one in less than 20 lines (funny for ones who can't resist). You just have to adhere the RFC 4180 spec which basically contains only 3 rules:
Fields are separated by a comma.
If a comma occurs within a field, then the field has to be surrounded by double quotes.
If a double quote occurs within a field, then the field has to be surrounded by double quotes and the double quote within the field has to be escaped by another double quote.
Here's a kickoff example:
public static <T> void writeCsv (List<List<T>> csv, char separator, OutputStream output) throws IOException {
BufferedWriter writer = new BufferedWriter(new OutputStreamWriter(output, "UTF-8"));
for (List<T> row : csv) {
for (Iterator<T> iter = row.iterator(); iter.hasNext();) {
String field = String.valueOf(iter.next()).replace("\"", "\"\"");
if (field.indexOf(separator) > -1 || field.indexOf('"') > -1) {
field = '"' + field + '"';
}
writer.append(field);
if (iter.hasNext()) {
writer.append(separator);
}
}
writer.newLine();
}
writer.flush();
}
Here's an example how you could use it:
public static void main(String[] args) throws IOException {
List<List<String>> csv = new ArrayList<List<String>>();
csv.add(Arrays.asList("field1", "field2", "field3"));
csv.add(Arrays.asList("field1,", "field2", "fie\"ld3"));
csv.add(Arrays.asList("\"field1\"", ",field2,", ",\",\",\""));
writeCsv(csv, ',', System.out);
}
And inside a Servlet (yes, Servlet, don't use JSP for this!) you can basically do:
protected void doGet(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException {
String filename = request.getPathInfo().substring(1);
List<List<Object>> csv = someDAO().findCsvContentFor(filename);
response.setHeader("content-type", "text/csv");
response.setHeader("content-disposition", "attachment;filename=\"" + filename + "\"");
writeCsv(csv, ';', response.getOutputStream());
}
Map this servlet on something like /csv/* and invoke it as something like http://example.com/context/csv/filename.csv. That's all.
Note that I added the possiblity to specify the separator character separately, because it may depend on the locale used whether Excel would accept a comma , or semicolon ; as CSV field separator. Note that I also added the filename to the URL pathinfo, because a certain webbrowser developed by a team in Redmond otherwise wouldn't save the download with the proper filename.
You will probably need a library to manipulate Excel files, like JExcelAPI ("jxl") or POI. I'm more familiar with jxl and it can certainly write files. You can generate them and store them by serving a URL to them but I wouldn't. Generated files are a pain. They add complication in the form on concurrency, clean-up processes, etc.
If you can generate the file on the fly and stream it to the client through the standard servlet mechanisms.
If it's generated many, may times or the generation is expensive then you can cache the result somehow but I'd be more inclined to keep it in memory than as a file. I'd certainly avoid, if you can, linking directly to the generated file by URL. If you go via a servlet it'll allow you to change your impleemntation later. It's the same encapsualtion concept as in OO dsign.
POI or JExcel are good APIs. I personally like better POI, plus POI is constantly updated. Furthermore, there are more resources online about POI than JExcel in case you have any questions. However, either of the two does a great job.
maybe you should consider using some reporting tool with an option of exporting files into XLS format. my suggestion is JasperReports
try {
String absoluteDiskPath = test.xls";
File f = new File(absoluteDiskPath);
response.setContentType("application/xlsx");
response.setHeader("Content-Disposition", "attachment; filename=" + absoluteDiskPath);
String name = f.getName().substring(f.getName().lastIndexOf("/") + 1, f.getName().length());
InputStream in = new FileInputStream(f);
out.clear(); //clear outputStream prevent illegalStateException write binary data to outputStream
ServletOutputStream outs = response.getOutputStream();
int bit = 256;
int i = 0;
try {
while ((bit) >= 0) {
bit = in.read();
outs.write(bit);
}
outs.flush();
outs.close();
in.close();
} catch (IOException ioe) {
ioe.printStackTrace();
} finally {
try {
if(outs != null)
outs.close();
if(in != null)
in.close();
}catch (Exception ioe2) {
ioe2.printStackTrace();
}
}
} catch (Exception ex) {
ex.printStackTrace();
}
I tried like as below in JSP, it is working fine.
<% String filename = "xyz.xls";
response.setContentType("application/octet-stream");
response.setHeader("Content-Disposition","attachment; filename=\"" + filename + "\"");
java.io.File excelFile=new java.io.File("C:\\Users\\hello\\Desktop\\xyz.xls");
java.io.FileInputStream fileInputStream=new java.io.FileInputStream(excelFile);
byte[] bytes = new byte[(int) excelFile.length()];
int offset = 0;
while (offset < bytes.length)
{
int result = fileInputStream.read(bytes, offset, bytes.length - offset);
if (result == -1) {
break;
}
offset += result;
}
javax.servlet.ServletOutputStream outs = response.getOutputStream();
outs.write(bytes);
outs.flush();
outs.close();
fileInputStream.close();
%>
I would like to save all attached files from an Excel (xls/HSSF) without extension.
I've been trying for a long time now, and I really don't know if this is even possible. I also tried Apache Tika, but I don't want to use Tika for this, because I need POI for other tasks, anyway.
I tried the sample code from the Busy Developers Guide, but this does not extract files in the old office format (doc, ppt, xls). And it throws an Error when trying to create new SlideShow(new HSLFSlideShow(dn, fs)) Error: (Remove argument to match HSLFSlideShow(dn))
My actual code is:
public static void saveEmbeddedXLS(InputStream fis_param, String embDIR) throws IOException, InvalidFormatException{
//HSSF - XLS
int i = 0;
System.out.println("Starting Embedded Search in xls...");
POIFSFileSystem fs = new POIFSFileSystem(fis_param);//create FileSystem using fileInputStream
HSSFWorkbook workbook = new HSSFWorkbook(fs);
for (HSSFObjectData obj : workbook.getAllEmbeddedObjects()) {
System.out.println("Objects : "+ obj.getOLE2ClassName());//the OLE2 Class Name of the object
String oleName = obj.getOLE2ClassName();//Document Type
DirectoryNode dn = (DirectoryNode) obj.getDirectory();//get Directory Node
//Trying to create an input Stream with the embedded document, argument of createDocumentInputStream should be: String; Where/How can I get this correct parameter for the function?
InputStream is = dn.createDocumentInputStream(dn);//This line is incorrect! How can I do i correctly?
FileOutputStream fos = new FileOutputStream("embDIR" + i);//Outputfilepath + Number
IOUtils.copy(is, fos);//FileInputStream > FileOutput Stream (save File without extension)
i++;
}
}
So my simple question is:
Is it possible to save ALL attachments from an xls file without any extension (as simple as possible)? And can any one provide me a solution? Many Thanks!
I have been trying to split one big PDF file to multiple pdf files based on its size. I was able to split it but it only creates one single file and rest of the file data is lost. Means it does not create more than one files to split it. Can anyone please help? Here is my code
public static void main(String[] args) {
try {
PdfReader Split_PDF_By_Size = new PdfReader("C:\\Temp_Workspace\\TestZip\\input1.pdf");
Document document = new Document();
PdfCopy copy = new PdfCopy(document, new FileOutputStream("C:\\Temp_Workspace\\TestZip\\File1.pdf"));
document.open();
int number_of_pages = Split_PDF_By_Size.getNumberOfPages();
int pagenumber = 1; /* To generate file name dynamically */
// int Find_PDF_Size; /* To get PDF size in bytes */
float combinedsize = 0; /* To convert this to Kilobytes and estimate new PDF size */
for (int i = 1; i < number_of_pages; i++ ) {
float Find_PDF_Size;
if (combinedsize == 0 && i != 1) {
document = new Document();
pagenumber++;
String FileName = "File" + pagenumber + ".pdf";
copy = new PdfCopy(document, new FileOutputStream(FileName));
document.open();
}
copy.addPage(copy.getImportedPage(Split_PDF_By_Size, i));
Find_PDF_Size = copy.getCurrentDocumentSize();
combinedsize = (float)Find_PDF_Size / 1024;
if (combinedsize > 496 || i == number_of_pages) {
document.close();
combinedsize = 0;
}
}
System.out.println("PDF Split By Size Completed. Number of Documents Created:" + pagenumber);
}
catch (Exception i)
{
System.out.println(i);
}
}
}
(BTW, it would have been great if you had tagged your question with itext, too.)
PdfCopy used to close the PdfReaders it imported pages from whenever the source PdfReader for page imports switched or the PdfCopy was closed. This was due to the original intended use case to create one target PDF from multiple source PDFs in combination with the fact that many users forget to close their PdfReaders.
Thus, after you close the first target PdfCopy, the PdfReader is closed, too, and no further pages are extracted.
If I interpret the most recent checkins into the iText SVN repository correctly, this implicit closing of PdfReaders is in the process of being removed from the code. Therefore, with one of the next iText versions, your code may work as intended.
Please tell me how to append data in docx file using java and docx4j.
What I'm doing is, I am using a template in docx format in which some field are dilled by java at run time,
My problem is for every group of data it creates a new file and i just want to append the new file into 1 file. and this is not done using java streams
String outputfilepath = "e:\\Practice/DOC/output/generatedLatterOUTPUT.docx";
String outputfilepath1 = "e:\\Practice/DOC/output/generatedLatterOUTPUT1.docx";
WordprocessingMLPackage wordMLPackage;
public void templetsubtitution(String name, String age, String gender, Document document)
throws Exception {
// input file name
String inputfilepath = "e:\\Practice/DOC/profile.docx";
// out put file name
// id of Xml file
String itemId1 = "{A5D3A327-5613-4B97-98A9-FF42A2BA0F74}".toLowerCase();
String itemId2 = "{A5D3A327-5613-4B97-98A9-FF42A2BA0F74}".toLowerCase();
String itemId3 = "{A5D3A327-5613-4B97-98A9-FF42A2BA0F74}".toLowerCase();
// Load the Package
if (inputfilepath.endsWith(".xml")) {
JAXBContext jc = Context.jcXmlPackage;
Unmarshaller u = jc.createUnmarshaller();
u.setEventHandler(new org.docx4j.jaxb.JaxbValidationEventHandler());
org.docx4j.xmlPackage.Package wmlPackageEl = (org.docx4j.xmlPackage.Package) ((JAXBElement) u
.unmarshal(new javax.xml.transform.stream.StreamSource(
new FileInputStream(inputfilepath)))).getValue();
org.docx4j.convert.in.FlatOpcXmlImporter xmlPackage = new org.docx4j.convert.in.FlatOpcXmlImporter(
wmlPackageEl);
wordMLPackage = (WordprocessingMLPackage) xmlPackage.get();
} else {
wordMLPackage = WordprocessingMLPackage
.load(new File(inputfilepath));
}
CustomXmlDataStoragePart customXmlDataStoragePart = wordMLPackage
.getCustomXmlDataStorageParts().get(itemId1);
// Get the contents
CustomXmlDataStorage customXmlDataStorage = customXmlDataStoragePart
.getData();
// Change its contents
((CustomXmlDataStorageImpl) customXmlDataStorage).setNodeValueAtXPath(
"/ns0:orderForm[1]/ns0:record[1]/ns0:name[1]", name,
"xmlns:ns0='EasyForm'");
customXmlDataStoragePart = wordMLPackage.getCustomXmlDataStorageParts()
.get(itemId2);
// Get the contents
customXmlDataStorage = customXmlDataStoragePart.getData();
// Change its contents
((CustomXmlDataStorageImpl) customXmlDataStorage).setNodeValueAtXPath(
"/ns0:orderForm[1]/ns0:record[1]/ns0:age[1]", age,
"xmlns:ns0='EasyForm'");
customXmlDataStoragePart = wordMLPackage.getCustomXmlDataStorageParts()
.get(itemId3);
// Get the contents
customXmlDataStorage = customXmlDataStoragePart.getData();
// Change its contents
((CustomXmlDataStorageImpl) customXmlDataStorage).setNodeValueAtXPath(
"/ns0:orderForm[1]/ns0:record[1]/ns0:gender[1]", gender,
"xmlns:ns0='EasyForm'");
// Apply the bindings
BindingHandler.applyBindings(wordMLPackage.getMainDocumentPart());
File f = new File(outputfilepath);
wordMLPackage.save(f);
FileInputStream fis = new FileInputStream(f);
ByteArrayOutputStream bos = new ByteArrayOutputStream();
byte[] buf = new byte[1024];
try {
for (int readNum; (readNum = fis.read(buf)) != -1;) {
bos.write(buf, 0, readNum);
}
// System.out.println( buf.length);
} catch (IOException ex) {
}
byte[] bytes = bos.toByteArray();
FileOutputStream file = new FileOutputStream(outputfilepath1, true);
DataOutputStream out = new DataOutputStream(file);
out.write(bytes);
out.flush();
out.close();
System.out.println("..done");
}
public static void main(String[] args) {
utility u = new utility();
u.templetsubtitution("aditya",24,mohan);
}
thanks in advance
If I understand you correctly, you're essentially talking about merging documents. There are two very simple approaches that you can use, and their effectiveness really depends on the structure and onward use of your data:
PhilippeAuriach describes one approach in his answer, which entails
appending all components within a MaindocumentPart instance to
another. In terms of the final docx file, this means the content
that appears in document.xml -- it won't take into account headers
and footers ( for example), but that may be fine for you.
You can insert multiple documents into a single docx file by inserting them
as AltChunk elements (see the docx4j documentation). This will
bring everything from one Word file into another, headers and all.
The downside of this is that your final document won't be a proper
flowing Word file until you open it and save it in MS Word itself
(the imported components remain as standalone files within the docx
bundle). This will cause you issues if you want to generated
'merged' files and then do something with them like render PDFs --
the merged content will simply be ignored.
The more complete (and complex) approach is to perform a "deep merge". This updates and maintains all references held within a document. Imported content becomes part of the main "flow" of the document (i.e. it is not stored as separate references), so the end result is a properly-merged file which can be rendered to PDF or whatever.
The downside to this is you need a good knowledge of docx structure and the API, and you will be writing a fair amount of code (I would recommend buying a license to Plutext's MergeDocx instead).
I had to deal with similar things, and here is what I did (probably not the most efficient, but working) :
create a finalDoc loading the template, and emptying it (so you have the styles in this doc)
for each data row, create a new doc loading the template, then replace your fields with your values
use the function below to append the doc filled with the datas to the finalDoc :
public static void append(WordprocessingMLPackage docDest, WordprocessingMLPackage docSource) {
List<Object> objects = docSource.getMainDocumentPart().getContent();
for(Object o : objects){
docDest.getMainDocumentPart().getContent().add(o);
}
}
Hope this helps.
I have this application I'm developing in JSP and I wish to export some data from the database in XLS (MS Excel format).
Is it possible under tomcat to just write a file as if it was a normal Java application, and then generate a link to this file? Or do I need to use a specific API for it?
Will I have permission problems when doing this?
While you can use a full fledged library like JExcelAPI, Excel will also read CSV and plain HTML tables provided you set the response MIME Type to something like "application/vnd.ms-excel".
Depending on how complex the spreadsheet needs to be, CSV or HTML can do the job for you without a 3rd party library.
Don't use plain HTML tables with an application/vnd.ms-excel content type. You're then basically fooling Excel with a wrong content type which would cause failure and/or warnings in the latest Excel versions. It will also messup the original HTML source when you edit and save it in Excel. Just don't do that.
CSV in turn is a standard format which enjoys default support from Excel without any problems and is in fact easy and memory-efficient to generate. Although there are libraries out, you can in fact also easily write one in less than 20 lines (funny for ones who can't resist). You just have to adhere the RFC 4180 spec which basically contains only 3 rules:
Fields are separated by a comma.
If a comma occurs within a field, then the field has to be surrounded by double quotes.
If a double quote occurs within a field, then the field has to be surrounded by double quotes and the double quote within the field has to be escaped by another double quote.
Here's a kickoff example:
public static <T> void writeCsv (List<List<T>> csv, char separator, OutputStream output) throws IOException {
BufferedWriter writer = new BufferedWriter(new OutputStreamWriter(output, "UTF-8"));
for (List<T> row : csv) {
for (Iterator<T> iter = row.iterator(); iter.hasNext();) {
String field = String.valueOf(iter.next()).replace("\"", "\"\"");
if (field.indexOf(separator) > -1 || field.indexOf('"') > -1) {
field = '"' + field + '"';
}
writer.append(field);
if (iter.hasNext()) {
writer.append(separator);
}
}
writer.newLine();
}
writer.flush();
}
Here's an example how you could use it:
public static void main(String[] args) throws IOException {
List<List<String>> csv = new ArrayList<List<String>>();
csv.add(Arrays.asList("field1", "field2", "field3"));
csv.add(Arrays.asList("field1,", "field2", "fie\"ld3"));
csv.add(Arrays.asList("\"field1\"", ",field2,", ",\",\",\""));
writeCsv(csv, ',', System.out);
}
And inside a Servlet (yes, Servlet, don't use JSP for this!) you can basically do:
protected void doGet(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException {
String filename = request.getPathInfo().substring(1);
List<List<Object>> csv = someDAO().findCsvContentFor(filename);
response.setHeader("content-type", "text/csv");
response.setHeader("content-disposition", "attachment;filename=\"" + filename + "\"");
writeCsv(csv, ';', response.getOutputStream());
}
Map this servlet on something like /csv/* and invoke it as something like http://example.com/context/csv/filename.csv. That's all.
Note that I added the possiblity to specify the separator character separately, because it may depend on the locale used whether Excel would accept a comma , or semicolon ; as CSV field separator. Note that I also added the filename to the URL pathinfo, because a certain webbrowser developed by a team in Redmond otherwise wouldn't save the download with the proper filename.
You will probably need a library to manipulate Excel files, like JExcelAPI ("jxl") or POI. I'm more familiar with jxl and it can certainly write files. You can generate them and store them by serving a URL to them but I wouldn't. Generated files are a pain. They add complication in the form on concurrency, clean-up processes, etc.
If you can generate the file on the fly and stream it to the client through the standard servlet mechanisms.
If it's generated many, may times or the generation is expensive then you can cache the result somehow but I'd be more inclined to keep it in memory than as a file. I'd certainly avoid, if you can, linking directly to the generated file by URL. If you go via a servlet it'll allow you to change your impleemntation later. It's the same encapsualtion concept as in OO dsign.
POI or JExcel are good APIs. I personally like better POI, plus POI is constantly updated. Furthermore, there are more resources online about POI than JExcel in case you have any questions. However, either of the two does a great job.
maybe you should consider using some reporting tool with an option of exporting files into XLS format. my suggestion is JasperReports
try {
String absoluteDiskPath = test.xls";
File f = new File(absoluteDiskPath);
response.setContentType("application/xlsx");
response.setHeader("Content-Disposition", "attachment; filename=" + absoluteDiskPath);
String name = f.getName().substring(f.getName().lastIndexOf("/") + 1, f.getName().length());
InputStream in = new FileInputStream(f);
out.clear(); //clear outputStream prevent illegalStateException write binary data to outputStream
ServletOutputStream outs = response.getOutputStream();
int bit = 256;
int i = 0;
try {
while ((bit) >= 0) {
bit = in.read();
outs.write(bit);
}
outs.flush();
outs.close();
in.close();
} catch (IOException ioe) {
ioe.printStackTrace();
} finally {
try {
if(outs != null)
outs.close();
if(in != null)
in.close();
}catch (Exception ioe2) {
ioe2.printStackTrace();
}
}
} catch (Exception ex) {
ex.printStackTrace();
}
I tried like as below in JSP, it is working fine.
<% String filename = "xyz.xls";
response.setContentType("application/octet-stream");
response.setHeader("Content-Disposition","attachment; filename=\"" + filename + "\"");
java.io.File excelFile=new java.io.File("C:\\Users\\hello\\Desktop\\xyz.xls");
java.io.FileInputStream fileInputStream=new java.io.FileInputStream(excelFile);
byte[] bytes = new byte[(int) excelFile.length()];
int offset = 0;
while (offset < bytes.length)
{
int result = fileInputStream.read(bytes, offset, bytes.length - offset);
if (result == -1) {
break;
}
offset += result;
}
javax.servlet.ServletOutputStream outs = response.getOutputStream();
outs.write(bytes);
outs.flush();
outs.close();
fileInputStream.close();
%>