学步园

1、第一种使用struts下载比较简单。需要继承DownloadAction。然后重写getStreamInfo方法。把InputStream流放入内部类中就行了。

package cn.finefuture.common.faxserver.struts;<br /> import java.io.IOException;<br /> import java.io.InputStream;<br /> import javax.servlet.http.HttpServletRequest;<br /> import javax.servlet.http.HttpServletResponse;<br /> import org.apache.struts.action.ActionForm;<br /> import org.apache.struts.action.ActionForward;<br /> import org.apache.struts.action.ActionMapping;<br /> import org.apache.struts.actions.DownloadAction;<br /> import cn.finefuture.common.faxserver.service.FaxServerService;<br /> import cn.finefuture.common.faxserver.service.impl.FaxServerServiceImp;<br /> public class FaxDownAction extends DownloadAction {<br /> private FaxServerService faxServerService = new FaxServerServiceImp();<br /> public void setFaxServerService(FaxServerService faxServerService) {<br /> this.faxServerService = faxServerService;<br /> }<br /> @Override<br /> protected StreamInfo getStreamInfo(ActionMapping mapping, ActionForm form,<br /> HttpServletRequest request, HttpServletResponse response)<br /> throws Exception {<br /> // 传真编号<br /> String faxId = request.getParameter("faxId");<br /> InputStream inStream = null;<br /> if (faxId != null && !(faxId.equals(""))) {<br /> //获取InputStream<br /> inStream = this.faxServerService.getFaxInAtt(faxId);<br /> }<br /> final InputStream in = inStream;<br /> final String contentType = "application/file";<br /> // 建<mce:script type="text/javascript" src="http://hi.images.csdn.net/js/blog/tiny_mce/themes/advanced/langs/zh.js" mce_src="http://hi.images.csdn.net/js/blog/tiny_mce/themes/advanced/langs/zh.js"></mce:script><mce:script type="text/javascript" src="http://hi.images.csdn.net/js/blog/tiny_mce/plugins/syntaxhl/langs/zh.js" mce_src="http://hi.images.csdn.net/js/blog/tiny_mce/plugins/syntaxhl/langs/zh.js"></mce:script>议设置content-disposition响应信息头，否则Web浏览器在下载文件时<br /> // 无法在保存文件对话框中显示正确的文件名<br /> response.setHeader("content-disposition", "attachment; filename="<br /> + faxId);<br /> return new DownloadAction.StreamInfo() // 使用隐式的方法实现了StreamInfo接口<br /> {<br /> public String getContentType() {<br /> return contentType;<br /> }<br /> public InputStream getInputStream() throws IOException {<br /> return in;<br /> }<br /> };<br /> }<br /> // 如果Struts动作不加file请求参数，则通过execute方法将指定目录中文件列表输出到客户端<br /> public ActionForward execute(ActionMapping mapping, ActionForm form,<br /> HttpServletRequest request, HttpServletResponse response)<br /> throws Exception {<br /> // 当file参数存在时，则调用DownloadAction中的execute方法<br /> // 实际上，在DownloadAction类中的execute方法调用了getStreamInfo方法<br /> // 这条语句就相当于调用了getStreamInfo方法<br /> return super.execute(mapping, form, request, response);<br /> }<br /> }<br />

2、第二种自己写输出流

/**<br /> * 下载附件<br /> *<br /> * @param mapping<br /> * @param form<br /> * @param request<br /> * @param response<br /> * @return<br /> */<br /> public ActionForward doDownLoadAttachment(ActionMapping mapping,<br /> ActionForm form, HttpServletRequest request,<br /> HttpServletResponse response) {<br /> // 传真编号<br /> String faxId = request.getParameter("faxId");<br /> InputStream inStream = null;<br /> if (faxId != null && !(faxId.equals(""))) {<br /> inStream = this.faxServerService.getFaxInAtt(faxId);<br /> }<br /> // 流不等于null<br /> if (inStream != null) {<br /> try {<br /> // 设置输出的格式<br /> response.reset();<br /> response.setContentType("bin");<br /> // 给中文字符转码<br /> faxId = new String(faxId.getBytes("GBK"), "iso8859-1");<br /> // 设置文件名<br /> response.setHeader("Content-Disposition",<br /> "attachment;filename=" + faxId);<br /> // 循环取出流中的数据<br /> byte[] b = new byte[1024];<br /> int len;<br /> while ((len = inStream.read(b)) > 0) {<br /> response.getOutputStream().write(b, 0, len);<br /> }<br /> } catch (IOException e) {<br /> e.printStackTrace();<br /> } finally {<br /> try {<br /> inStream.close();<br /> } catch (IOException e) {<br /> e.printStackTrace();<br /> }<br /> }<br /> }<br /> return null;<br /> }