导出excel

OutputStream outp = null;
try
{
outp = response.getOutputStream();
A service=new A();
service.downFile(outp,conn);
}catch(Exception e){

}
public void downFile(OutputStream out,Connection conn)throws Exception {

try{
String sql = "";
File file = new File(a+".xls");

WritableWorkbook wb = jxl.Workbook.createWorkbook(file);
WritableSheet sheet = wb.createSheet("a", 0);
String[] str={"","",""};
WritableCellFormat format1=new WritableCellFormat();
format1.setAlignment(jxl.format.Alignment.CENTRE);//设置为居中
for(int i=0;i<str.length;i++){
//设置每一列的宽度
sheet.setColumnView(i, 20);
Label label = new Label(i,0,str[i],format1);
sheet.addCell(label);
}
ResultSet rs = null;
int sDataLine = 1;
while(rs.next()){
int sLable=0;
while(sLable<17)
{
sheet.addCell(new Label(sLable,sDataLine,rs.getString(sLable+1)));
sLable = sLable + 1 ;
}
sDataLine = sDataLine +1;
}
rs.close();
wb.write();
wb.close();
FileInputStream fileInputStream=new FileInputStream(file);
byte bytes[]=new byte[1024];
int len=0;
while((len=fileInputStream.read(bytes))!=-1)
{
out.write(bytes,0,len);
}
fileInputStream.close();

}catch (Exception e) {
e.printStackTrace();
}
}