Java学习之道：Java操作Excel之导出下载

Love The Way You Lie 2021-09-10 09:20 331阅读 0赞

页面放置一个按钮进行点击导出事件  
<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) \{

// 文件名称与路径  
  String realPath = request.getRealPath("");  
  String fileName = "导出的文件名.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(执行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, "没有定义评价对象名称！");  
    \}  
    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;  
 \}