Http协议（下载）

public class DownServlet extends HttpServlet {

@Override
protected void service(HttpServletRequest req, HttpServletResponse resp)throws ServletException, IOException {

resp.setContentType("application/force-download");//协议设置1

String fileName = "1.jpg";
InputStream fin = DownServlet.class.getClassLoader().getResourceAsStream(fileName);

fileName = "我的图片.jpg";
fileName = URLEncoder.encode(fileName,"UTF-8");//如果不编码,浏览器中显示的文件名是乱码
resp.setHeader("Content-Disposition","attachment;filename=\""+fileName+"\"");//协议设置2 ---告诉浏览器，当前所下载文件的文件名

//FileInputStream fin = new FileInputStream(fileName);

OutputStream out = resp.getOutputStream();
byte buf[] = new byte[512];
int len=0;
while( (len=fin.read(buf))!=-1){
out.write(buf, 0, len);
}
}
}