response.setContentType("application/pdf");
FileInputStream in;
OutputStream out;
//路径
String path = "I:\\622.pdf";
try {
in = new FileInputStream(new File(path));
out = response.getOutputStream();
byte[] b = new byte[512];
while ((in.read(b)) != -1) {
out.write(b);
}
out.flush();
in.close();
out.close();
} catch (IOException e) {
e.printStackTrace();
}