servlet 中的下载链接

Question

我正在尝试下面的代码在 servlet 中创建下载链接。但这是行不通的。请检查或给我另一个代码或方法...

public class Downlord1 extends HttpServlet {
    int BYTES_DOWNLOAD=1024;
protected void processRequest(HttpServletRequest request, HttpServletResponse response)
        throws ServletException, IOException {
    response.setContentType("text/html;charset=UTF-8");
    PrintWriter out = response.getWriter();
    try {
       response.setHeader("Content-Disposition","attachment;Filename=dp.jpg");
       ServletContext ctx=getServletContext();
       InputStream is=ctx.getResourceAsStream("/images/krishna.jpg");
       int read=0;
       byte[] bytes=new byte[BYTES_DOWNLOAD];
       OutputStream os=response.getOutputStream();
       while((read=is.read(bytes))!=-1)
       {
       os.write(bytes,0, read);

       }
       os.flush();
       os.close();


    } finally {            
        out.close();
    }
}

// <editor-fold defaultstate="collapsed" desc="HttpServlet methods. Click on the + sign on the left to edit the code.">
/** 
 * Handles the HTTP <code>GET</code> method.
 * @param request servlet request
 * @param response servlet response
 * @throws ServletException if a servlet-specific error occurs
 * @throws IOException if an I/O error occurs
 */
@Override
protected void doGet(HttpServletRequest request, HttpServletResponse response)
        throws ServletException, IOException {
    processRequest(request, response);
}

/** 
 * Handles the HTTP <code>POST</code> method.
 * @param request servlet request
 * @param response servlet response
 * @throws ServletException if a servlet-specific error occurs
 * @throws IOException if an I/O error occurs
 */
@Override
protected void doPost(HttpServletRequest request, HttpServletResponse response)
        throws ServletException, IOException {
    processRequest(request, response);
}

/** 
 * Returns a short description of the servlet.
 * @return a String containing servlet description
 */
@Override
public String getServletInfo() {
    return "Short description";
}// </editor-fold>

}

Answer 1

将内容类型更改为image/jpeg。

删除 PrintWriter out = response.getWriter(); - 未使用它，并且可能会导致多次调用 response.getWriter 或 .getOutputStream 出现问题。