Servlet 下载文件代码详解编程语言

public class DownloadServlet extends HttpServlet { 
    private static final long serialVersionUID = 1L; 
  
     
    private static final int BUFSIZE = 4096; 
    String filePath = null; 
   
    protected void doGet(HttpServletRequest request, 
            HttpServletResponse response) throws ServletException, IOException { 
   
        filePath = getServletContext().getRealPath("") + File.separator + "abc.txt"; 
          
        File file = new File(filePath); 
        int length = 0; 
        ServletOutputStream outStream = response.getOutputStream(); 
        response.setContentType("text/html"); 
        response.setContentLength((int) file.length()); 
        String fileName = (new File(filePath)).getName(); 
        response.setHeader("Content-Disposition", "attachment; filename=/""+ fileName + "/""); 
   
        byte[] byteBuffer = new byte[BUFSIZE]; 
        DataInputStream in = new DataInputStream(new FileInputStream(file)); 
   
        while ((in != null) && ((length = in.read(byteBuffer)) != -1)) { 
            outStream.write(byteBuffer, 0, length); 
        } 
   
        in.close(); 
        outStream.close(); 
    } 
  
}