poi生成excel下拉菜单

在web开发中常用到生成excel模板，在用excel poi生成excel模板时，常用到生成excel下拉菜单。下面是生成excel下拉菜单的代码：

package poiexcel;

　　import java.io.FileOutputStream;

　　import java.util.Date;

　　import org.apache.poi.hssf.usermodel.DVConstraint;

　　import org.apache.poi.hssf.usermodel.HSSFCell;

　　import org.apache.poi.hssf.usermodel.HSSFDataValidation;

　　import org.apache.poi.hssf.usermodel.HSSFRow;

　　import org.apache.poi.hssf.usermodel.HSSFSheet;

　　import org.apache.poi.hssf.usermodel.HSSFWorkbook;

　　import org.apache.poi.hssf.util.CellRangeAddressList;

　　public class POI

　　{

　　public static void main(String [] args)

　　{

　　String [] list={"东软","华信","SAP","海辉"};

　　new POI().createListBox(list);

　　return;

　　}

　　public void createListBox (String [] list)

　　{

　　//文件初始化

　　HSSFWorkbook wb = new HSSFWorkbook();

　　HSSFSheet sheet = wb.createSheet("new sheet");

　　//在第一行第一个单元格，插入下拉框

　　HSSFRow row = sheet.createRow(0);

　　HSSFCell cell = row.createCell(0);

　　//普通写入操作

　　cell.setCellValue("请选择");//这是实验

　　//生成下拉列表

　　//只对（0，0）单元格有效

　　CellRangeAddressList regions = new CellRangeAddressList(0,0,0,0);

　　//生成下拉框内容

　　DVConstraint constraint = DVConstraint.createExplicitListConstraint(list);

　　//绑定下拉框和作用区域

　　HSSFDataValidation data_validation = new HSSFDataValidation(regions,constraint);

　　//对sheet页生效

　　sheet.addValidationData(data_validation);

　　//写入文件

　　FileOutputStream fileOut;

　　try {

　　fileOut = new FileOutputStream("workbook.xls");

　　wb.write(fileOut);

　　fileOut.close();

　　} catch (Exception e) {

　　// TODO Auto-generated catch block

　　e.printStackTrace();

　　}

　　//结束

　　System.out.println("Over");

　　}

　　}

 上面的代码中，下拉菜单的内容是在list中写死的，在开发的过程中往往是会用到“动态”生成下拉菜单的内容，在这里记录代码，一来有助于自己积累，二来将经验与大家分享：

public void downLoadModle() throws IOException, RowsExceededException, WriteException{		
          String jgId = this.getParameter("jgId");
           List<BaseTrainType> childrenList = (List<BaseTrainType>) pxlbManager.findByHql(" from BaseTrainType b where b.parentId="+pxlb+" and b.id in (select trainTypeId from OrgBaseTrainType where orgBaseId="+jgId+")");
		
          String path = "/excel模板.xls";
          String templetDire = this.getRequest().getSession().getServletContext().getRealPath("/common");
          FileInputStream finput = new FileInputStream(path);    //从工程目录下下载模板
       POIFSFileSystem pss = new POIFSFileSystem(finput);
          HSSFWorkbook workbook = new HSSFWorkbook(pss);
          //读取Sheet
          HSSFSheet sheet = workbook.getSheetAt(0);
          CellRangeAddressList regions = new CellRangeAddressList(1, 65535, 12, 12);  //excel下拉菜单作用域，例子中是第12列(从0开始)
          String [] list= new String[childrenList.size()];;
          for (int i=0;i<childrenList.size();i++) {
	list[i] =  childrenList.get(i).getTypeNum()+"-"+childrenList.get(i).getTypeName(); //加载下拉菜单中的内容
       }
           DVConstraint constraint = DVConstraint.createExplicitListConstraint(list); //将list中的内容写入到excel中
       HSSFDataValidation data_validation = new HSSFDataValidation(regions,constraint); //绑定下拉菜单和作用域
       sheet.addValidationData(data_validation); //对sheet生效
           			
           this.getResponse().setContentType("application/vnd.ms-excel");
           String fileName = URLEncoder.encode(name, "UTF-8");
           this.getResponse().setHeader("Content-Disposition","attachment; filename=" + fileName+pxbjNum+ ".xls");
           ServletOutputStream out = this.getResponse().getOutputStream(); 
           workbook.write(out);
 }