Java学习之道：Java操作Excel之导出下载

页面放置一个button进行点击导出事件

<h:commandLink target="_parent" value="导出"

           action="#{eveluatesubject.doSaveExcel}"

           styleClass="cssButtonBG">

</h:commandLink>

          

后台的导出方法

/**

  * 导出EXCEL

  * 

  * @param request

  * @return

  */

 public String doSaveExcel() {

  HttpServletRequest request = (HttpServletRequest) FacesContext

    .getCurrentInstance().getExternalContext().getRequest();

  dooutof(request);

return null;

 }

public String dooutof(HttpServletRequest request) {

// 文件名与路径

  String realPath = request.getRealPath("");

  String fileName = "导出的文件名称.xls";

  File file = new File(realPath + "//xxfzpj//tempPath//");//导出文件存放的位置

  if (!file.exists()) {

   file.mkdirs();

  }

  realPath = realPath + "//xxfzpj//tempPath//" + fileName;

// 建立工作薄并写表头

  try {

   WritableWorkbook wwb = Workbook.createWorkbook(new File(realPath));

   WritableSheet ws = wwb.createSheet("Sheet1", 0);// 建立工作簿

// 写表头

   jxl.write.Label label1 = new jxl.write.Label(0, 0, "列1");

   jxl.write.Label label2 = new jxl.write.Label(1, 0, "列2");

   jxl.write.Label label3 = new jxl.write.Label(2, 0, "列3");

   jxl.write.Label label4 = new jxl.write.Label(3, 0, "列4");

   jxl.write.Label label5 = new jxl.write.Label(4, 0, "列5");

ws.addCell(label1);// 放入工作簿

   ws.addCell(label2);

   ws.addCell(label3);

   ws.addCell(label4);

   ws.addCell(label5);

// 写入信息

   List<Map> listmsg = 数据库中读出的内容(运行SQL);

for (int i = 0; i < listmsg.size(); i++) {

    label1 = new jxl.write.Label(0, i + 1, listmsg.get(i).get(

      "subject_id").toString().trim());// 建立第一列

    label2 = new jxl.write.Label(1, i + 1, listmsg.get(i).get(

      "subject_name").toString().trim());// 建立第二列

    if (listmsg.get(i).get("object_name") != null

      && "" != listmsg.get(i).get("object_name")) {

     label3 = new jxl.write.Label(2, i + 1, listmsg.get(i).get(

       "object_name").toString().trim());// 建立第三列

    } else {

     label3 = new jxl.write.Label(2, i + 1, "未定义评价对象名称！");

    }

    label4 = new jxl.write.Label(3, i + 1, listmsg.get(i).get(

      "mode_name").toString().trim());// 建立第四列

    label5 = new jxl.write.Label(4, i + 1, listmsg.get(i).get(

      "type_name").toString().trim());// 建立第五列

    ws.addCell(label1);// 放入工作簿

    ws.addCell(label2);

    ws.addCell(label3);

    ws.addCell(label4);

    ws.addCell(label5);

   }

// 写入Exel工作表

   wwb.write();

   // 关闭Excel工作薄对象

   wwb.close();

// 下载

   FacesContext ctx = FacesContext.getCurrentInstance();

String contentType = "application/x-download";

   HttpServletResponse response = (HttpServletResponse) ctx

     .getExternalContext().getResponse();

response.setContentType(contentType);

   response.setHeader("Content-Disposition", "attachment;filename="

     + new String(fileName.getBytes("gb2312"), "ISO8859-1"));

   HttpServletRequest request1 = (HttpServletRequest) FacesContext

     .getCurrentInstance().getExternalContext().getRequest();

ServletOutputStream out = response.getOutputStream();

byte[] bytes = new byte[0xffff];

   InputStream is = new FileInputStream(new File(realPath));

   int b = 0;

   while ((b = is.read(bytes, 0, 0xffff)) > 0) {

    out.write(bytes, 0, b);

   }

   is.close();

   out.flush();

   ctx.responseComplete();

} catch (Exception e) {

   // TODO Auto-generated catch block

   e.printStackTrace();

  }// 此处建立路径

  return null;

 }