java导出Excel文件

import java.io.File;
import java.io.FileOutputStream;
import java.io.IOException;
import java.io.OutputStream;
import jxl.Workbook;
import jxl.write.Label;
import jxl.write.WritableSheet;
import jxl.write.WritableWorkbook;
import jxl.write.WriteException;
import java.util.List;
import java.util.Map;
import javax.servlet.http.HttpServletRequest;
import javax.servlet.http.HttpServletResponse;

	public void exportExcel(List<DTO> list, String fileName, Map<String,String> headName) throws WriteException,IOException{
    	OutputStream os = new FileOutputStream(new File(fileName));
        //创建工作薄
        WritableWorkbook workbook = Workbook.createWorkbook(os);
        //创建新的一页
        WritableSheet sheet = workbook.createSheet("列表",0);
        //生成列表标题
        Map<String,Object> dataMap;
        int row = 0, cell = 0;
        if(headName == null){
        	headName = (Map<String,String>)list.get(0);
        }
		for(String key : headName.keySet()){
			Label label = new Label(cell, row ,headName.get(key));
			sheet.addCell(label);
			cell++;
		}
		//生成内容
    	for(row = 0;row < list.size();row++){
    		cell = 0;
    		dataMap = (Map<String,Object>)list.get(row);
    		for(String key : headName.keySet()){
    			Label label = new Label(cell, row + 1 ,dataMap.get(key).toString());
    			sheet.addCell(label);
    			cell++;
    		}
    	}
        workbook.write();
        workbook.close();
        os.close();
    }