jsp文件下载,jsp文件下载失败
jsp页面如何实现下载文档
jsp页面下载文档是在jsp中有一个a标签 ，当用户点击a标签的时候下载文件。
一般采用href属性直接指向一个服务器地址，只要链接的文件存在,就会给出弹出保存对话框.
点击a标签 先执行onclick事件，再请求href中指向的地址。
前端jsp：
a href="#" onclick="javascript:downloadtest('${app.id}')" id="pluginurl" style="color: #83AFE2;text-decoration:underline;"/a
然后在js中：
function downloadtest(id){
var url = "%=request.getContextPath()%/app/download" + "/" + id;
$("#pluginurl").attr("href",url);
}
后台处理下载逻辑的java代码：
/**
* 下载文件
* @param id appid
* @param response
*/
@RequestMapping(value="/download/{id}")
public void download(@PathVariable String id, HttpServletResponse response){
String filepath = "";
Result result = appService.getAppById(id);
App app = (App) result.getMap().get("app");
if(app == null){
return;
}
filepath = app.getUrl();
File file = new File(filepath);
InputStream inputStream = null;
OutputStream outputStream = null;
byte[] b= new byte[1024];
int len = 0;
try {
inputStream = new FileInputStream(file);
outputStream = response.getOutputStream();
response.setContentType("application/force-download");
String filename = file.getName();
filename = filename.substring(36, filename.length());
response.addHeader("Content-Disposition","attachment; filename=" + URLEncoder.encode(filename, "UTF-8"));
response.setContentLength( (int) file.length( ) );
while((len = inputStream.read(b)) != -1){
outputStream.write(b, 0, len);
}
} catch (Exception e) {
e.printStackTrace();
}finally{
if(inputStream != null){
try {
inputStream.close();
inputStream = null;
} catch (IOException e) {
e.printStackTrace();
}
}
if(outputStream != null){
try {
outputStream.close();
outputStream = null;
} catch (IOException e) {
e.printStackTrace();
}
}
}
}
jsp下载文件前提示是否成功
不能判断。jsp下载文件前提示最简单的方式是在网页上做超级链接，但是，这样服务器上的目录资源会直接暴露给最终用户，会给网站带来一些不安全的因素。jsp下载文件可以存在于任何服务器能够取得到的地方，而客户端不一定能直接得到，所以提示不能作为结果直接判断。
jsp实现文件的下载
%@pagelanguage="java" import="java.io.*,java.net.*" contentType="application/x-msdownload" pageEncoding="UTF-8"%%
//关于文件下载时采用文件流输出的方式处理：
//加上response.reset()，并且所有的％后面不要换行，包括最后一个；
String url = request.getParameter("url");
System.out.print(url);
int k = url.lastIndexOf("\\");
String url1=url.substring(k+1,url.length());
response.reset();//可以加也可以不加
response.setContentType("application/x-download");
String filedownload = url;
String filedisplay = url1;
filedisplay = URLEncoder.encode(filedisplay,"UTF-8");
response.addHeader("Content-Disposition","attachment;filename=" + filedisplay);
OutputStream outp = null;
FileInputStream in = null;
try
{
outp = response.getOutputStream();
in = new FileInputStream(filedownload);
byte[] b = new byte[1024];
int i = 0;
while((i = in.read(b)) 0)
{
outp.write(b, 0, i);
}
out.clear();
out = pageContext.pushBody();
outp.flush();
}
catch(Exception e)
{
System.out.println("Error!");
}
finally
{
if(in != null)
{
in.close();
in = null;
}
if(outp != null)
{
outp.close();
outp = null;
}
}
%
jsp 如何实现文件上传和下载功能？
上传：
MyjspForm mf = (MyjspForm) form;// TODO Auto-generated method stub
FormFile fname=mf.getFname();
byte [] fn = fname.getFileData();
OutputStream out = new FileOutputStream("D:\\"+fname.getFileName());
Date date = new Date();
String title = fname.getFileName();
String url = "d:\\"+fname.getFileName();
Upload ul = new Upload();
ul.setDate(date);
ul.setTitle(title);
ul.setUrl(url);
UploadDAO uld = new UploadDAO();
uld.save(ul);
out.write(fn);
out.close();
下载：
DownloadForm downloadForm = (DownloadForm)form;
String fname = request.getParameter("furl");
FileInputStream fi = new FileInputStream(fname);
byte[] bt = new byte[fi.available()];
fi.read(bt);
//设置文件是下载还是打开以及打开的方式msdownload表示下载；设置字湖集，//主要是解决文件中的中文信息
response.setContentType("application/msdownload;charset=gbk");
//文件下载后的默认保存名及打开方式
String contentDisposition = "attachment; filename=" + "java.txt";
response.setHeader("Content-Disposition",contentDisposition);
//设置下载长度
response.setContentLength(bt.length);
ServletOutputStream sos = response.getOutputStream();
sos.write(bt);
return null;