HSSFWorkbook 導出excel java

public String exportExcelList(){
//創建webbook,對應一個excel文件
HSSFWorkbook wb = new HSSFWorkbook();
//在webbook中添加一個sheet,對應excel中的sheet
HSSFSheet sheet = wb.createSheet("檢查單");
//在sheet中添加表頭,添加一行
HSSFRow row = sheet.createRow(0);
//設置每一列的寬,此處可根據實際情況設置.
sheet.setColumnWidth(1, 20*256);
sheet.setColumnWidth(6, 20*256);
sheet.setColumnWidth(7, 20*256);
sheet.setColumnWidth(8, 20*256);
sheet.setColumnWidth(11, 20*256);
sheet.setColumnWidth(12, 20*256);
sheet.setColumnWidth(13, 20*256);
//設置表格樣式
HSSFCellStyle style = wb.createCellStyle();
style.setAlignment(HSSFCellStyle.ALIGN_LEFT);//內容向左靠齊
Font font = wb.createFont();//為字體設計樣式
font.setFontHeightInPoints((short)12); //字體大小
font.setFontName("宋體");
style.setFont(font);//將字體加入到表格樣式中
//設置列名稱(第一列)
HSSFCell cell = row.createCell(0);
cell.setCellValue("id");//列名稱
cell.setCellStyle(style);//列樣式
//第二列
cell = row.createCell(1);
cell.setCellValue("syncDate");
cell.setCellStyle(style);
.........
//查出你要的數據
List laboratoryList = laboratoryInformationService.getInformationByTime(timeHelper);
//遍歷數據
for(int i=0;i<laboratoryList.size();i++){
//創建行
row = sheet.createRow(i+1);
Map<String,Object> laboratoryMap = new HashMap<String,Object>();//臨時變量
laboratoryMap = (Map<String, Object>) laboratoryList.get(i);
//給每一行設置單元格
//第一列
cell = row.createCell(0);//列索引
cell.setCellValue(laboratoryMap.get("id").toString());//單元格內容
cell.setCellStyle(style);//列的樣式
//第二列
cell = row.createCell(1);
cell.setCellValue(laboratoryMap.get("syncDate").toString());
cell.setCellStyle(style);
............
}
//將excel的數據寫入文件
HttpServletResponse res = ServletActionContext.getResponse();
res.setContentType("octets/stream");
String excelName = "檢查單";//文件名字
//轉碼防止亂碼
try {
res.addHeader("Content-Disposition", "attachment;filename="+new String( excelName.getBytes("gb2312"), "ISO8859-1" )+".xls");
} catch (UnsupportedEncodingException e) {
// TODO Auto-generated catch block
e.printStackTrace();
}
OutputStream os;
try {
os = res.getOutputStream();
wb.write(os);
os.flush();
os.close();
} catch (IOException e) {
// TODO Auto-generated catch block
e.printStackTrace();

}
System.out.println("excel導出成功");
return null;//此處一定要為null否則報錯
}