最近做Flex里的Excel下载，用as3xls进行Excel导出后，Excel修改编辑后老出现：不能以当前格式保存。。。若要保存所做的更改，请单击“确定”，然后将其另存为最新的格式。
最后通过JAVA的POI实现Excel下载的，具体实现思路：
1.DataGrid数据传到服务器。
2.打开Excel模板。
3.向模板写入数据。
4.客户端下载写好的Excel。
前台Flex代码
public function ToExcel(dg:AdvancedDataGrid,name:String)
{
var url:String="http://localhost:8080/Demo/servlet/ExcelServlet";
var variables:URLVariables = new URLVariables();
variables.head = convertDGHead(dg);
variables.data = convertDGData(dg); var request:URLRequest = new URLRequest(url);
request.method = URLRequestMethod.POST;
request.data = variables; var fileReference:FileReference=new FileReference();
fileReference.download(request,name+".xls");
fileReference.addEventListener(Event.COMPLETE,doEvent); }
private function doEvent(evt:Event):void {
Alert.show("下载完成");
}
//表头转为字符串，用";"隔开
private function convertDGHead(dg:AdvancedDataGrid):String {
var str:String = '';
for(var i:int = 0;i<dg.columns.length;i++) {
if(dg.columns[i].headerText != undefined) {
str+=dg.columns[i].headerText+";";
} else {
str+=dg.columns[i].dataField+";";
}
}
return str;
} //表内容转为字符串，用";"隔开
private function convertDGData(dg:AdvancedDataGrid):String {
var str:String = '';
for(var j:int =0;j<dg.dataProvider.length;j++)
{
for(var k:int=0; k < dg.columns.length; k++) {
if(dg.dataProvider.getItemAt(j) != undefined && dg.dataProvider.getItemAt(j) != null) {
if(dg.columns[k].labelFunction != undefined) {
str += dg.columns[k].labelFunction(dg.dataProvider.getItemAt(j),dg.columns[k].dataField)+";";
} else {
str += dg.dataProvider.getItemAt(j)[dg.columns[k].dataField]+";";
}
}
}
}
return str;
}
web.xml中增加：
<servlet>
<servlet-name>ExcelServlet</servlet-name>
<servlet-class>com.test.ExcelServlet</servlet-class>
</servlet> <servlet-mapping>
<servlet-name>ExcelServlet</servlet-name>
<url-pattern>/servlet/ExcelServlet</url-pattern>
</servlet-mapping>
后台JAVA代码：
package com.test; import java.io.File;
import java.io.FileInputStream;
import java.io.IOException; import javax.servlet.ServletException;
import javax.servlet.http.HttpServlet;
import javax.servlet.http.HttpServletRequest;
import javax.servlet.http.HttpServletResponse; import org.apache.poi.hssf.usermodel.HSSFCell;
import org.apache.poi.hssf.usermodel.HSSFCellStyle;
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.poifs.filesystem.POIFSFileSystem; public class ExcelServlet extends HttpServlet {
private static final long serialVersionUID = 1L; public ExcelServlet() {
super();
} public void destroy() {
super.destroy(); // Just puts "destroy" string in log
// Put your code here
} public void doGet(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException {
doMainDispatch(request, response);
} public void doPost(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException {
doMainDispatch(request, response);
} public void init() throws ServletException {
// Put your code here
} protected void doMainDispatch(HttpServletRequest req, HttpServletResponse resp) throws ServletException, IOException {
String filename = "excel.xls";
resp.reset();
req.setCharacterEncoding("UTF-8");
resp.setCharacterEncoding("UTF-8");
resp.setContentType("application/vnd.ms-excel");
resp.addHeader("Content-Disposition", "attachment; filename=\"" + filename + "\"");
String head = req.getParameter("head");
String data = req.getParameter("data");
HSSFWorkbook wb = generateExcel(head,data);
wb.write(resp.getOutputStream());
resp.getOutputStream().flush();
resp.getOutputStream().close();
req.getInputStream().close();
} private HSSFWorkbook generateExcel(String head, String data) throws IOException {
String tmp = (new File("")).getCanonicalPath();
//如果不是只有一级 如："d:\tomcat6\bin"
if(tmp.indexOf("bin") != -1)
{
tmp = tmp.substring(0, tmp.lastIndexOf("\\"))
+ "\\webapps\\Demo\\model\\Model.xls";
}
else //只有一级 如："d:\tomcat6"
{
tmp += "\\webapps\\Demo\\model\\Model.xls";
} //创建输出数据文件
File modelFile =new File(tmp);
// 路径下不存在此模板文件
if (!modelFile.getParentFile().exists()) {
return null;
}
else{
FileInputStream fileinputstream = new FileInputStream(tmp);
POIFSFileSystem poifsfilesystem = new POIFSFileSystem(fileinputstream);
HSSFWorkbook wb = new HSSFWorkbook(poifsfilesystem);
HSSFSheet sheet = wb.getSheetAt(0); String[] headArr = head.split(";");
String[] dataArr = data.split(";"); for(int rowNum=0; rowNum<=dataArr.length/headArr.length; rowNum++)
{
HSSFRow row = sheet.getRow(rowNum);
HSSFCellStyle rowstyle=null;
if(row == null) //如果模板中没有这一行，则新建
{
row = sheet.createRow(rowNum);
}
else //如果有这一行，获取样式
{
rowstyle = row.getRowStyle();
} for(int colNum=0; colNum<headArr.length; colNum++)
{
HSSFCell cell = row.getCell(colNum);
HSSFCellStyle cellstyle=null;
if(cell == null){
cell = row.createCell(colNum);
}else{
cellstyle = cell.getCellStyle();
} if(cellstyle != null)
cell.setCellStyle(cellstyle);
else if(rowstyle != null)
cell.setCellStyle(rowstyle);
}
}
return wb;
}
}
}
注：
1.给Servlet传值时HTTP有参数长度的限制，参数超过时必须指定为POST方法，此次传Excel文件内容，不能用GET方法，因此要加上request.method = URLRequestMethod.POST;
2.flex中隐含为utf-8编码，因此必须含有request.setCharacterEncoding("UTF-8")语句来编码接收的数据，也必须含有response.setCharacterEncoding("UTF-8");语句以编码输出数据，否则会出现汉字乱码。
3、tomcat6在默认状态下最大的post请求是2M ，以此要在server.xml文件中设maxPostSize属性
<Connector port="8080" protocol="HTTP/1.1"
connectionTimeout="20000"
redirectPort="8443" maxPostSize="0" />
maxPostSize： 0 表示不限制 单位为：byte
本文参考链接：http://pufan53.iteye.com/blog/903468
POST相关限制文章：http://blog.****.net/jackyren007/article/details/3715444