文件下载
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1)、普通下载
不安全，
下载人员可以直接看到下载地址，可以盗链接
随时可以下载
<a href="soft/a.rar">软件下载</a>
html5 新属性
<a href="soft/a.rar" download>软件下载</a>
<a href="imgs/girl.jpg" download>美女图片下载</a>
<a href="/user.jsp" download>jsp程序下载</a>
2)、安全下载
必须登录才可以下载
下载人，从来不知道文件在服务器那个地方
springmvc 框架内置文件安全下载
@RequestMapping("/down")
public ResponseEntity<byte[]> down(HttpServletRequest req) throws IOException {
String f = req.getServletContext().getRealPath("/imgs/") + "girl.jpg";
File file = new File(f);
byte[] body = null;
InputStream is = new FileInputStream(file);
body = new byte[is.available()];
is.read(body);
HttpHeaders headers = new HttpHeaders();
headers.add("Content-Disposition", "attchement;filename=" + file.getName());
HttpStatus statusCode = HttpStatus.OK;
ResponseEntity<byte[]> entity = new ResponseEntity<byte[]>(body, headers, statusCode);
return entity;
}
@RequestMapping("/download")
public ResponseEntity<byte[]> download(HttpServletRequest req, HttpServletResponse res) throws IOException {
ResponseEntity<byte[]> entity = null;
HttpSession session = req.getSession();
if(session.getAttribute("member")==null){
res.setCharacterEncoding("utf-8");
PrintWriter out = res.getWriter();
out.print("请登录，登录后才可以下载...");
out.flush();
out.close();
}else {
String name = req.getParameter("name");
byte[] body = null;
String f = req.getServletContext().getRealPath("/download/") + name;
File file = new File(f);
InputStream is = new FileInputStream(file);
body = new byte[is.available()];
is.read(body);
HttpHeaders headers = new HttpHeaders();
headers.add("Content-Disposition", "attchement;filename=" + file.getName());
HttpStatus statusCode = HttpStatus.OK;
entity = new ResponseEntity<byte[]>(body, headers, statusCode);
}
return entity;
}
3)、java web通用的下载实现
@RequestMapping("/mydown") @ResponseBody
public void mydown(HttpServletRequest req, HttpServletResponse resp) throws IOException {
String fileName = req.getParameter("name");
if (fileName == null) {
resp.setCharacterEncoding("utf-8");
PrintWriter out = resp.getWriter();
out.print("没有下载的文件...");
out.flush();
out.close();
} else {
resp.setContentType("application/force-download");// 设置强制下载不打开
String fn = new SimpleDateFormat("yyyyMMddhhmmssS").format(new Date())+fileName.substring(fileName.lastIndexOf("."));
resp.addHeader("Content-Disposition", "attachment;fileName=" + fn);// 设置文件名
String path = req.getServletContext().getRealPath("/download/"); //文件下载源路径
File file = new File(path, fileName);
byte[] buf = new byte[10240];
FileInputStream fis = null;
BufferedInputStream bis = null;
try {
fis = new FileInputStream(file);
bis = new BufferedInputStream(fis);
OutputStream os = resp.getOutputStream();
int i = bis.read(buf);
while (i != -1) {
os.write(buf, 0, i);
i = bis.read(buf);
}
} catch (Exception e) {
e.printStackTrace();
} finally {
if (bis != null) {
try {
bis.close();
} catch (IOException e) {
e.printStackTrace();
}
}
if (fis != null) {
try {
fis.close();
} catch (IOException e) {
e.printStackTrace();
}
}
}
}
}
使用方法
<h3>jsp自己实现下载</h3>
<a href="mydown?name=girl.jpg" download>girl-mydown</a>
<a href="mydown?name=m.jsp" download>jsp</a>
<a href="mydown?id=60">文档下载</a>