JSF implementation for Excel generation and download!

Package CN. CCB. Elms. Common;

Import java. Io. file;
Import java. Io. fileinputstream;
Import java. Io. fileoutputstream;
Import java. Io. ioexception;
Import java. util. arraylist;
Import java. util. iterator;
Import java. util. List;
Import javax. Faces. Context. facescontext;
Import javax. servlet. servletoutputstream;
Import javax. servlet. http. httpservletresponse;

Import org. Apache. Poi. hssf. usermodel. hssfcell;
Import org. Apache. Poi. hssf. usermodel. hssfcellstyle;
Import org. Apache. Poi. hssf. usermodel. hssffont;
Import org. Apache. Poi. hssf. usermodel. hssfrow;
Import org. Apache. Poi. hssf. usermodel. hssfsheet;
Import org. Apache. Poi. hssf. usermodel. hssfworkbook;

/**
* <P> Function Description: operations related to File Download </P>
* @ Author gjg
* @ Version 1.0
*/
Public class downloadutil
{
/**
* Generate an Excel file in two-dimensional array format
* @ Param datalist string [] []
*/
Public static void genericexcel (string datalist [] [])
{
String strfilename = "";
Try
{
// Generate an Excel file and save it on the server
Ssconfig SSC = new ssconfig ();
String strzfilename = "query _" + SSC. getpolicimestamp (); // main file name
Strfilename = strzfilename + ". xls"; // full name of the file
Fileoutputstream fileout = new fileoutputstream (strfilename );
Hssfworkbook WB = new hssfworkbook ();
Hssfcellstyle cs = WB. createcellstyle (); // format object
Hssffont fcol = WB. createfont (); // font object, Header
Fcol. setfontheightinpoints (short) 10 );
Fcol. setboldweight (fcol. boldweight_bold );
// Worksheet
Hssfsheet sheet = WB. createsheet (0 + "");
WB. setsheetname (0, strzfilename, (short) 1 );
// Put the first row in the header
Hssfrow ROW = NULL;

Int nrownum = 0;
For (INT nH = 0; NH <datalist. length; NH ++)
{
Row = sheet. createrow (nrownum); // create a row
For (INT nk = 0; NK <datalist [0]. length; NK ++)
{
Hssfcell cell = row. createcell (short) (NK ));
Cell. setencoding (hssfcell. encoding_utf_16 );
Cell. setcellvalue (datalist [NH] [NK]); // write a cell
// Set the header to center in bold
If (nrownum = 0)
{
CS. setfont (fcol );
CS. setalignment (hssfcellstyle. align_center );
Cell. setcellstyle (CS );
}
}
Nrownum ++;
}
WB. Write (fileout );
Fileout. Close ();

}
Catch (exception E)
{
E. printstacktrace ();
}
// Download an object based on the provided file name
Downloadfile (strfilename );
}

/**
* Generate an Excel file in List format
* @ Deprecated
* @ Param colname_zh list
* @ Param data list
*/
Public static void genericexcel2 (list colname_zh, list data)
{
String strfilename = "";
Try
{
If (colname_zh = NULL | DATA = NULL)
{
Throw new exception ("the number of columns in the table header or the number of data columns is empty! ");
}

// Generate an Excel file and save it on the server
Ssconfig SSC = new ssconfig ();
String strzfilename = "query _" + SSC. getpolicimestamp (); // main file name
Strfilename = strzfilename + ". xls"; // full name of the file
Fileoutputstream fileout = new fileoutputstream (strfilename );
Hssfworkbook WB = new hssfworkbook ();
Hssfcellstyle cs = WB. createcellstyle (); // format object
Hssffont fcol = WB. createfont (); // font object, Header
Fcol. setfontheightinpoints (short) 10 );
Fcol. setboldweight (fcol. boldweight_bold );
// Worksheet
Hssfsheet sheet = WB. createsheet (0 + "");
WB. setsheetname (0, strzfilename, (short) 1 );
// Put the first row in the header
Hssfrow ROW = NULL;
Row = sheet. createrow (short) 0 );
Int ny = 0;
For (iterator iter = colname_zh.iterator (); ITER. hasnext ();)
{
Hssfcell cell = row. createcell (short) ny );
Cell. setencoding (hssfcell. encoding_utf_16 );
CS. setfont (fcol );
CS. setalignment (hssfcellstyle. align_center );
Cell. setcellstyle (CS );
Cell. setcellvalue (ITER. Next () + "");
NY ++;
}
// X indicates the starting row of data.
// Y indicates which column the data is filled
Int Nx = 1; // The data starts from the first row.
For (iterator itert = data. iterator (); itert. hasnext ();)
{
NY = 0;
Row = sheet. createrow (short) Nx );
Arraylist Al = (arraylist) itert. Next ();
For (iterator iter2 = al2.iterator (); iter2.hasnext ();)
{
Hssfcell cell = row. createcell (short) ny );
Cell. setencoding (hssfcell. encoding_utf_16 );
// CS. setfont (fcol );
CS. setalignment (hssfcellstyle. align_center );
// Cell. setcellstyle (CS );
Cell. setcellvalue (iter2.next () + "");
NY ++;
}
NX ++;
}
WB. Write (fileout );
Fileout. Close ();
}
Catch (exception E)
{
E. printstacktrace ();
}
// Download an object based on the provided file name
Downloadfile (strfilename );
}

/**
* <P> Function Description: download an object based on the provided file name </P>
* @ Param strfilename string
* @ Return void
*/
Private Static void downloadfile (string strfilename)
{
Try
{
File exportfile = new file (strfilename );
Httpservletresponse = (httpservletresponse)
Facescontext. getcurrentinstance ().
Getexternalcontext (). getresponse ();
Servletoutputstream = httpservletresponse.
Getoutputstream ();
Httpservletresponse. setheader ("content-disposition ",
"Attachment; filename =" + strfilename );
Httpservletresponse. setcontentlength (INT) exportfile. Length ());
Httpservletresponse. setcontenttype ("application/X-download ");
Byte [] B = new byte [1024];
Int I = 0;
Fileinputstream FCM = new java. Io. fileinputstream (exportfile );
While (I = FCM. Read (B)> 0)
{
Servletoutputstream. Write (B, 0, I );
}
}
Catch (ioexception E)
{
E. printstacktrace ();
}
Facescontext. getcurrentinstance (). responsecomplete ();
}

Public static void main (string [] ARGs)
{
// Genericexcel () Usage
String s [] [] = new string [] []
{
{
"Column 1", "column 2", "column 3", "column 4 "},
{
"A", "22", "33", "44 "}
};
Genericexcel (s );

// Genericexcel2 () Usage
// Al indicates the header
Arraylist Al = new arraylist ();
Al. Add ("");
Al. Add ("B ");
Al. Add ("C ");
// Al2 indicates multiple rows of data
Arraylist Al = new arraylist ();
// A3 indicates a row of data
Arraylist _3 = new arraylist ();
Al3.add ("1 ");
Al3.add ("2 ");
Al3.add ("3 ");
Al2.add (_3 );
A3 = new arraylist (); // a new arraylist object must be created here.
Al3.add ("11 ");
Al3.add ("22 ");
Al3.add ("33 ");
Al2.add (_3 );
Genericexcel2 (Al, Al );
}

}