I'm trying to read excel file and pass all the data to DB. I found a few code examples but all of them required external jars. How can I read excel files using only the standard library?
IF you don't want to use a library then you will have to download the Excel file format specs from MS and write an Excel parser yourself (which is extremely complicated and takes > 10 years for one developer). For the OpenXML format spec see here and here.
Thus I really recommend using a library for that...
Try Apache POI - a free Java library for dealing with MS Office documents..
You can save as the excel file *.cvs and sperated ";". Then, you can read file line by line and get the columns which is getting from each token.
Microsoft excel uses a binary way to save its data, so manually reading excel files might be a hassle. If you could convert the excel (xls) to a comma seperated values (csv) file, then you can just read the file and split your input on the comma's.
This is a difficult problem. First off, it is not as simple as "adding a third party library". There are no existing EXCEL reading libraries that do not cost money and the one that I know that does work is very expensive AND has bugs in it.
One strategy is to create an Excel add in that reads the data and transfers it to your application by OLE or the clipboard or by a TCP/IP port or saves it to a temporary file. If you look in the source code for OPeNDAP.org's ODC project you can find an Excel add in and TCP capability to do this.
You can try referring to the reader in OpenOffice which is open source code, however, in my opinion that code is not easily refactorable into a private project for various reasons.
Microsoft has components and tools to open Excel files and expose them via COM objects.
You can also learn the BIFF format and write your own parser. You probably would want to write a parser for BIFF5, but be forewarned, this is a BIG project, even if you only parse a limited number of data types.
Related
In the existing project user can download report and it has 10 million records, this process gets data from database and writes to csv by using super csv java api then sends an email to user by attaching, it takes huge heap space to hold 10 million java objects and writing these records to csv files, because of this server is crashing and going down as application has many reports like this. is there any better way to handle this.? I red sxssfworkbook documentation and it says specified records count can keep in memory and remaining records will be pushed to hard disk but this is using to create excel files. is there any similar api to create csv files or sxssfworkbook can be used to create csv files.?
There are few Java libraries for reading and writing CSV files. They typically support "streaming", so they do not have the problem of needing to hold the source data or the generated CSV in memory.
The Apache Commons CSV library would be a good place to start. Here is the User Guide. It supports various of flavors of CSV file, including the CSV formats generated by Microsoft Excel.
However, I would suggest that sending a CVS file containing 10 million records (say 1GB uncompressed data) is not going to make you popular with the people who run your users' email servers! Files that size should be made available via an web or file transfer service.
I has a excel file with 4 excel sheets in it. Now i want to read or write to required excel sheets using java without using any third party lib.
I know i can read and write data using FileInputStream and FileOutputStream respecitvely. But i can handle the work sheets??
No, you can'not, There is numerous way in Java for reading/writing files, but there is no built-in support for MS Office/Excel spreadsheets. http://poi.apache.org/ - is a key to victory.
If your goal is to interface with data from an excel sheet from your Java application, I'd suggest to use the solutions suggested by other posters, it will save you a lot of work.
If, however, you want to be able to read excel files from Java (or any other programming language for that matter) 'just because you can' then you could take a look at this file and read the instructions on this web-page. I would warn you that it would take considerably more time to implement your own API if you base it only on the file-specs that are publicly available. You might want to check out the work done by the people from the Apache POI project to get an idea of how to approach it. Or (even better) contribute to the project. Here you can find out how to go about doing that
I want to store the values from the database to an existing excel file. For example if the file is stored in C: data.xls. I want the data from db table to be stored in that.
I will mention the column name in the excel file itself.
Please help me to do this.
Use JDBC API to read/fetch result from the MySql database and jExcelAPI or Apache POI (recommended) to write/update excel document.
Writing to a CSV file is probably the easiest way to do this. CSV files can be opened up in Excel, but cannot have any text formatting. See the CSV Wikipedia article for more details on the format.
If you would rather use an XLS or XLSX format, consider using Apache POI, as the formats of those file types (particularly XLS) is quite complicated to write to manually.
If you are going for a CSV file, you need only open the file, and begin putting rows, one per line, with commas in between values. It's very simple, and works with a variety of software.
I have a directory where files are constantly updated. I need to read the latest excel file and convert it into tab delimited file. It is under windows. A batch + java solution will work for me. Or if I can use excel in command line programatically that also works
I would disagree with those people who recommend Apache POI. The best API that I know of for dealing with Excel is Andy Khan's JExcel.
It has already been widely suggested, POI is probably the most complete "pure Java" implementation of Excel.
In one API you get support for Excel 2003 and 2007.
However, you need to be weary of its memory footprint. It is a hog. If you use it, make sure you use the event-driven model it supports as this will reduce footprint and execute faster.
In Java you can use, for example, Apache POI library to read data from Excel files. And then use standard Java facilities to write data into tab delimited file.
You can read in the excel sheet using POI and then iterate through the cells, writing them out to a separate file with appropriate delimiters.
Have a look at other SQ question: convert Excel to csv either using shell script or jython . if so how
I answered with PyODConverter, but there is jodconverter: Java version of this tool. It uses OpenOffice working as a service. I use it to convert between various file formats.
You can use Apache POI API for reading the excel file and OpenCSV for writing the CSV file.
The interop library is slow and needs MS Office installed.
Many times you don't want to install MS Office on servers.
I'd like to use Apache POI, but I'm on .NET.
I need only to extract the text portion of the files, not creating nor "storing information" in Office files.
I need to tell you that I've got a very large document library, and I can't convert it to newer XML files.
I don't want to write a parser for the binaries files.
A library like Apache POI does this for us. Unfortunately, it is only for the Java platform. Maybe I should consider writing this application in Java.
I am still not finding an open source alternative to POI in .NET, I think I'll write my own application in Java.
For all MS Office versions:
You could use the third-party components like TX Text Controls for Word and TMS Flexcel Studio for Excel
For the new Office (2007):
You could do some basic stuff using .net functionality from system.io.packaging. See how at http://msdn.microsoft.com/en-us/library/bb332058.aspx
For the old Office (before 2007):
The old Office formats are now documented: http://www.microsoft.com/interop/docs/officebinaryformats.mspx. If you want to do something really easy you might consider trying it. But be aware that these formats are VERY complex.
Check out the Aspose components. They are designed to mimic the Interop functionality without requiring a full Office install on a server.
As the new docx formats are inherently XML based files, you can create and manipulate them programmatically with standard XML DOM techniques, once you know the structure.
The files are basically zip archives with an alternate file extension. Use the System.IO.Packaging namespace to get access to the internal elements of the file, then open them into a XmlDocument to perform the manipulation.
There are examples available for doing this, and the Office Open XML project on SourceForge may be worth looking at for inspiration.
As for the older binary formats, these were proprietary to MS, and the only way you're likely to get at the content from within is through the Office object model (requires an Office install), or a third party file converter/parser.
Unfortunately there's nothing first party and native to the .NET platform to work with these files.
What do you need to do with those file? If you just want to stream them to the user, then the basic file streams are fine. If you want to create new files (perhaps based on a template) to send to the user that the user can open in Office, there are a variety or work-arounds.
If you're actually keeping data in Office documents for use by your web site, you're doing it wrong. Office documents, even Excel spreadsheets and access databases, are not really an appropriate choice for use with an interactive web site.
If the document is in word 2007 format, you can use the system.io.packaging library to interact with it programatically.
RWendi
In Java world, there is also JExcelApi. It is very clearly written, from what I was able to see, much cleaner then POI. So maybe even a port of that code to .NET is not out of the question, depending of course you have enough of time on your hands.
OpenOffice.
You can program against it and have it do a lot for you, without spending the money on a license for the server, or have the vulnerability associated with it on your server.
Microsoft Excel workbooks can be read using an ODBC driver (or is it an OLE DB driver? can't remember) that makes the workbook look like a database table. But I don't know whether that driver is available without the Office Suite itself.
You can use OpenOffice. It has a command-line conversion tool:
Conversion Howto
In short, you define a macro in OpenOffice and you call that macro with a command-line
argument to OpenOffice. In that argument the name of the local file (the Office file) is
encoded.
It's not a great sollution, but it should be workable.