Demo：servlet实现图片的上传

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本文链接： https://blog.csdn.net/u013644146/article/details/98633044

一个简单的servlet例子，实现图片的上传功能，上传的图片给  HttpServletResponse 对象

public class BackGroundLogoServlet extends HttpServlet
{
     private static final Logger m_logger=Logger.getLogger (BackGroundLogoServlet. class);
     
     @Override
     public void init(ServletConfig config) throws ServletException {
            super.init(config);
            m_logger.debug ( "BackGroundLogoServlet init.");
     }
     
     @Override
     protected void doGet(HttpServletRequest request, HttpServletResponse response)
                 throws ServletException{   
           response.setContentType( "image/png");
           response.setHeader( "Access-Control-Allow-Origin", "*");
           String fileName = request.getParameter( "filename");//获取参数值titlebar_logo.png
           File file = new File( "D:\\"+ fileName);//读取D:\\titlebar_logo.png图片
           FileInputStream fis = null;
           BufferedOutputStream out= null;
           try
           {
                fis = new FileInputStream(file);
                out = new BufferedOutputStream(response.getOutputStream());
                byte[] buffer= new byte[1024];
                int len;
                while((len=fis.read(buffer))!=-1)
                {
                    //read the file from local disk
                    //write to client
                    out.write(buffer, 0, len);     
                    out.flush();
                    m_logger.debug ( "background pic upload success !");
                }
           }
           catch (FileNotFoundException e)
           {
               try
               {
                   response.reset();
                   //set content type once again
                   response.setContentType("text/html;charset=utf-8" );
                   //give error message to client
                   response.getWriter().println( "文件未找到" );
               }
               catch (IOException e1)
               {
                   e1.printStackTrace();
               }
               e.printStackTrace();
           }
           catch (IOException e)
           {
               e.printStackTrace();
           }
           finally
           {
               try
               {
                   if(fis!= null){
                   fis.close();
               }
               if(out!= null){
                   out.close();
               }
           }
           catch (IOException e)
           {
                e.printStackTrace();
           }
        }
           
     }