直入主题，上代码。

//导出excel
@RequestMapping(value=http://www.mamicode.com/"excel")
public void excel(String excelname,String title,@RequestParam("district3") String district3,@RequestParam("district4") String district4,@RequestParam("pname")String pname,@RequestParam("ename") String ename, OutputStream os,HttpServletResponse response) throws Exception{
response.setContentType("application/vnd.ms-excel");
//response.addHeader("Content-Disposition", "attachment;filename=\""+excelname+".xls\"");
String excelname_=new String(excelname.getBytes("gbk"), "ISO8859-1");
response.addHeader("Content-Disposition", "attachment; filename=\""
+ excelname_ + ".xls\"");
WritableWorkbook workbook = Workbook.createWorkbook(os);
WritableSheet sheet = workbook.createSheet(excelname, 0); //生成名为excelname的工作表，参数0表示这是第一页 
   WritableFont font1= new WritableFont(WritableFont.TIMES,18,WritableFont.BOLD); 
WritableCellFormat format1=new WritableCellFormat(font1); 
format1.setAlignment(jxl.format.Alignment.CENTRE);//设置为居中
format1.setVerticalAlignment(VerticalAlignment.CENTRE); //设置垂直居中;
format1.setBorder(jxl.format.Border.RIGHT,jxl.format.BorderLineStyle.THIN,Colour.BLACK);
format1.setBorder(jxl.format.Border.BOTTOM,jxl.format.BorderLineStyle.NONE);
//给列设置宽度;  
sheet.setColumnView(0,10);
sheet.setColumnView(1,35);
        sheet.setColumnView(2, 35);  
        sheet.setColumnView(3, 15);  
        sheet.setColumnView(4, 15);  
        sheet.setColumnView(5, 15);
        sheet.setColumnView(6, 35);
        sheet.setColumnView(7, 35);
        sheet.setColumnView(8, 20);
        sheet.setColumnView(9, 35);

sheet.mergeCells(0,0,9,0);
Label label=new Label(0,0,title,format1); //创建表头, 在Label对象的构造子中指名单元格位置是第一列第一行(0,0) 
   sheet.addCell(label); 
   sheet.setRowView(0,800);//设置第一行高度
   
   //设置填报单位
   sheet.mergeCells(0,1,9,1);
   font1= new WritableFont(WritableFont.TIMES,14,WritableFont.BOLD); 
   format1=new WritableCellFormat(font1); 
   format1.setBorder(jxl.format.Border.RIGHT,jxl.format.BorderLineStyle.THIN,Colour.BLACK);
   format1.setVerticalAlignment(VerticalAlignment.CENTRE); //设置垂直居中;
label=new Label(0,1,"填报单位： （盖章）",format1); //创建表头, 在Label对象的构造子中指名单元格位置是第一列第一行(0,0) 
   sheet.addCell(label); 
   sheet.setRowView(1,600);//设置第一行高度
   
   sheet.setRowView(2,500);
font1=new WritableFont(WritableFont.createFont("楷体_GB2312"),12,WritableFont.BOLD);
WritableCellFormat format2=new WritableCellFormat(font1);
format2.setAlignment(jxl.format.Alignment.CENTRE);//设置为居中
format2.setVerticalAlignment(VerticalAlignment.CENTRE); //设置垂直居中;
//format2.set
//设置边框
   format2.setBorder(jxl.format.Border.ALL,jxl.format.BorderLineStyle.THIN,Colour.BLACK);
     
   int startindex=2;
label=new Label(0,startindex,"序号",format2); 
   sheet.addCell(label); 
label=new Label(1,startindex,"演练组织单位",format2);
sheet.addCell(label); 
label=new Label(2,startindex,"演练科目名称",format2);
sheet.addCell(label); 
label=new Label(3,startindex,"演练类型",format2);
sheet.addCell(label); 
label=new Label(4,startindex,"演练内容",format2);
sheet.addCell(label); 
label=new Label(5,startindex,"演练时间",format2);
sheet.addCell(label);
label=new Label(6,startindex,"演练地点",format2);
sheet.addCell(label);
label=new Label(7,startindex,"拟参加应急演练的单位及部门",format2);
sheet.addCell(label);
label=new Label(8,startindex,"拟参加演练的人数",format2);
sheet.addCell(label);
label=new Label(9,startindex,"备注",format2);
sheet.addCell(label);

/*生成一个保存数字的单元格 
必须使用Number的完整包路径，否则有语法歧义 
单元格位置是第二列，第一行，值为789.123 
jxl.write.Number number = new jxl.write.Number(2,0,789.123); 
sheet.addCell(number); */
jxl.write.Number number=null;


//从数据库查询数据
Map<String, String> map=new HashMap<String, String>();
Map<String, String> like=new HashMap<String, String>();
if(StringUtils.notNull(district3)){
map.put("s.district3", district3);
}
if(StringUtils.notNull(district3)){
map.put("s.district4", district4);
}
if(StringUtils.notNull(pname)){
map.put("plansdrillname", pname);
}
if(StringUtils.notNull(ename)){
like.put("s.enterprisename", ename);
}
List<CpPlansdrillDto> dtos = cpPlansdrillService.getStatisticsList(map, like, 1,10000);
font1=new WritableFont(WritableFont.createFont("楷体_GB2312"),10,WritableFont.NO_BOLD);
format2=new WritableCellFormat(font1);
format2.setAlignment(jxl.format.Alignment.CENTRE);//设置为居中
format2.setVerticalAlignment(VerticalAlignment.CENTRE); //设置垂直居中;
format2.setWrap(true);//自动换行
format2.setBorder(jxl.format.Border.ALL,jxl.format.BorderLineStyle.THIN,Colour.BLACK);
//数据保存
for (int i = 0; i <dtos.size(); i++) 
{    
CpPlansdrillDto m=dtos.get(i);
String data=http://www.mamicode.com/"";
if(m.getPlansdrilldate()!=null){
SimpleDateFormat sdf=new SimpleDateFormat("yyyy-MM-dd");  
java.util.Date date=new java.util.Date();  
data=http://www.mamicode.com/sdf.format(date);
}
int pcount=0;
if(StringUtils.notNull(m.getPlansdrillcount())){
pcount=Integer.parseInt(m.getPlansdrillcount());
}
String deparmetn=StringUtils.notNull(m.getPlansdrilldepartment())?m.getPlansdrilldepartment():"";
number = new jxl.write.Number(0,i+startindex+1,i+1,format2); 
   sheet.addCell(number);
label=new Label(1,i+startindex+1,m.getPlansdrillunits(),format2);
sheet.addCell(label);
label=new Label(2,i+startindex+1,m.getPlansdrillname(),format2);
sheet.addCell(label);
label=new Label(3,i+startindex+1,m.getPlansdrilltype().equals("1")?"现场演练":"桌面演练",format2);
sheet.addCell(label);
label=new Label(4,i+startindex+1,m.getPlansdrillcontent().equals("1")?"单项演练":"综合演练",format2);
sheet.addCell(label);
label=new Label(5,i+startindex+1,data,format2);  
   sheet.addCell(label); 
label=new Label(6,i+startindex+1,m.getPlansdrilladdress(),format2);
sheet.addCell(label);
label=new Label(7,i+startindex+1,deparmetn,format2);
sheet.addCell(label);
number=new jxl.write.Number(8,i+startindex+1,pcount,format2);
   sheet.addCell(number);
label=new Label(9,i+startindex+1,m.getNote(),format2);
sheet.addCell(label);
    }

workbook.write();
workbook.close();
os.close();
response.flushBuffer();
}

java 导出excel