Source: www.javaworld.com
Author Elango Sundaram
summary
Many institutions use Microsoft Excel forms as information exchange, many non-professional programmers, business analysts, and project managers can use this technology. The ability to use Java from the Excel documentation, collect, and consolidate the ability of data, prove is very useful. JAKARTA POI (Poor Obfuscation Implementation, no confusion) enables programmers to quickly complete these tasks. POI can be used to perform the exchange of file formats based on Microsoft OLE (Object Links and Embedded) technology in pure Java to composite document formats such as software used by Microsoft Excel, Microsoft Word. This article analyzes POI and explains how to read and write Microsoft Excel documents using Java and provide an interesting instance using the POI API.
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Whether your information on your hand is an asset stable table, the downloaded account information, bills or salary, which may eventually enter Microsoft Excel spare. Even if it is not a professional IT person, people will also be able to use Excel's data exchange technology. Jakarta Poi API is a wonderful party that makes it easy to access Microsoft document formats for Java programmers. The most mature API in Jakarta Poi is the HSSF (Horrible Spreadsheet Format) API, which is used to access the Excel document.
In this article, I will take you to create and read Excel documents, and using fonts and cell styles - all of this is done in Java.
POI glossary
The following is listed below, and the key terms related to POI are listed below:
l Poifs (Poor Obfuscation Implementation File System): Read, write Ole to the API group in the composite document format.
l HSSF (Horrible Spreadsheet Format): Read and write the API of Microsoft Excel.
l HDF (HORRIBLE Document Format): Read and write the API of Microsoft Word 97.
l HPSF (Horrible Property SET FORMAT): Read the API set by the property.
Create an Excel document
Jakarta OPI can be used to create an Excel document, the main steps are as follows:
l Create a file Workbook: hssfworkbook workbook = new hssfworkbook ();
l Create a worksheet called "Java Excels" in Workbook Worksheet: hssfsheet sheet = workbook.createsheet ("Java Excels");
l Create a new line Row in the table sheet Row: hssfrow rot = Sheet.createrow ((Short) 0);
l Create a single product Cell Cell: hssfcell cell = row.createcell (short);
l Place the content in units: Cell.SetCellValue ("Have a Cup of XL");
l Write Workbook into the file: Workbook.write (FileoutputStream);
Read data from Excel documents
In this example, you will see how to read values from the Excel document.
Let us imagine an Excel form that will be used:
EMPLOYEE NAME
Specialization
Designation
Anbu
Programmingsenior Programmer PROGRAMMER
Jason
Banking industrial
Business Analyst
Ramesh
Databases
DBA
Mackyb
Accounting
Delivery Head
Key Steps to read the Excel table:
l Create a reference to the Excel document: hssfworkbook workbook = new fileinputstream (new fileinputstream (filetoberead);
l Quote: By default, reference to "0" of the first table in the Excel document: hssfsheet sheet = workbook.getsheetat (0); a table can also be referenced by its name. We assume that the name of this form is "sheet1". It can be referenced by this: hssfsheet sheet = workbook.getsheet ("sheet1");
l Quote: hssfrow rot = sheet.Getrow (0);
l A number of cells in the list: hssfcell cell = row.getcell ((Short) 0);
l Number of data values in cells: Cell.getstringcellValue ();
Example:
Now suppose we want to get information about all public methods and data members in a JAR file, all of which can be collected into a table of a separate file. We expect to see the name of the class in the first column of the table, the second column is the field, the third list is a method, and each column is shown in red.
The program is to complete the following:
l Decompress the JAR file
l Read all class file code in the JAR file
l Loading these classes
l By reflex mechanism, get the name of the method and field
l Write information such as the class and fields using Jakarta Poi to the Excel table
Now we focus on using Jakarta Poi's most interesting steps:
l Create a new Excel document: workbook = new hssfworkbook ();
l Create a worksheet in the Excel document and naming for this table: Sheet = Workbook.createsheet ("Java Class Info");
l Set the width of the first three columns: Sheet.SetColumnWidth (Short) 0, (Short) 1000);
l Create a head: hssfrow rot = sheet.createrow ((Short) 0);
l Create a style of fonts and cells:
HSSFFONT FONT = Workbook.createFont ();
Font.SetColor (hssffont.color_red);
Font.setBoldweight (HSSFFont.BoldWeight_Bold);
// Create the Style
HSSfcellStyle CellStyle = workbook.createcellstyle ();
CellStyle.SetFont (font);
l Use the cell style:
HSSfcell Cell = row.createcell ((Short) 0);
Cell.setcellStyle (CellStyle);
Cell.setcellType (hssfcell.cell_type_string);
Cell.SetCellValue ("class name"); l Output file:
FileOutputStream Fout = New FileOutputStream (OutputFile);
// Write the Excel Sheet
Workbook.write (fout);
Fout.flush ();
// done deal. Close IT.
Fout.close ();
to sum up
As shown in this article, Java developers do not need to be critical in the face of the Excel form. We can easily deal with the Excel documentation. Drink a cup of coffee, put Excel after the brain.
About author
Elango Sundaram is a senior Java programmer, dedicated to research distributed computing systems, agents based on technologies and object-oriented methods. He has a master's degree in Virginia University and composes distributed computing using jini and WebSphere Studio Application Developer Tail Plug-in (for WSAD 4.0).
references
This article download: http://www.javaworld.com/javaworld/jw-03-2004/poi/jw-0322-poi.zip
Jakarta Poi Site: http://jakarta.apache.org/poi/
For more information about POI, please refer to "It's Poi-Fect," Tony Sintes (JavaWorld, May 2002): http://www.javaworld.com/javaworld/javaqa/2002-05/01-qa-0503-excel3.html
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