在做excel导出时如何将excel直接写在输出流中

之前做excel导出时，我都是先将文件写在服务器上，然后再下载下来，后来发现原来可以直接将文件写在输出流里边。

下面是一个小demo:

package com.huaqin.fcstrp.util;  

import java.io.IOException;
import java.io.OutputStream;
import java.io.UnsupportedEncodingException;
import java.net.URLEncoder;  

import javax.servlet.http.HttpServletResponse;  

import org.apache.poi.hssf.usermodel.HSSFWorkbook;
import org.apache.poi.ss.usermodel.Cell;
import org.apache.poi.ss.usermodel.Row;
import org.apache.poi.ss.usermodel.Sheet;  

public class WriteExcle {  

    private HSSFWorkbook workbook = null;
    /**
     *
     * @param response 下载请求的response
     */
    public void createExcel(HttpServletResponse response){  

        //创建workbook
        workbook = new HSSFWorkbook();
        //添加Worksheet（不添加sheet时生成的xls文件打开时会报错)
        Sheet sheet1 = workbook.createSheet("sheet1");
        OutputStream out = null;
        try {
            out = response.getOutputStream();
            String fileName = "test.xls";// 文件名
            response.setContentType("application/x-msdownload");
            response.setHeader("Content-Disposition", "attachment; filename="
                                                    + URLEncoder.encode(fileName, "UTF-8"));
            Row row = workbook.getSheet("sheet1").createRow(0);    //创建第一行
            for(int i = 0;i < 10;i++){
                Cell cell = row.createCell(i);
                cell.setCellValue("测试数据"+i);
            }
            workbook.write(out);
        } catch (Exception e) {
            e.printStackTrace();
        } finally {
            try {
                out.close();
            } catch (IOException e) {
                e.printStackTrace();
            }
        }
    }
}  

调用：

/**
     * 下载2
     * @param request
     * @param response
     * @return
     * @throws FileNotFoundException
     */
    @RequestMapping(value = "/download2")
    @ResponseBody
    public void download2(HttpServletRequest request,
            HttpServletResponse response) throws FileNotFoundException {
         WriteExcel writeExcle = new WriteExcel();
         writeExcel.createExcel(response);  

    }