传入id，文件下载

一时失言乱红尘 2022-06-02 03:59 110阅读 0赞

话不多说，并不难，看代码就可以，重点是response.setContentType和response.setHeader两个的设置

import java.io.BufferedInputStream;
    import java.io.BufferedOutputStream;
    import java.io.FileInputStream;
    import java.io.IOException;
    import java.io.InputStream;
    import java.io.OutputStream;
    import java.net.URLEncoder;
    
    import javax.servlet.ServletException;
    import javax.servlet.http.HttpServlet;
    import javax.servlet.http.HttpServletRequest;
    import javax.servlet.http.HttpServletResponse;
    
    import com.nxmu.uploadOrdownload.app.beans.fileupload;
    import com.nxmu.uploadOrdownload.app.dao.Impl.fileuploadDao;
    
    public class filedowloadServlet extends HttpServlet { 
        private static final long serialVersionUID = 1L;
        private fileuploadDao dao = new fileuploadDao();
        protected void doGet(HttpServletRequest request, HttpServletResponse response) 
                throws ServletException, IOException {
            int id = Integer.parseInt(request.getParameter("id"));
            fileupload fileUpload = dao.getBean(id);
            response.setContentType("application/x-msdownload");
            response.setHeader("Content-Disposition", "attachment;filename=" 
                    + URLEncoder.encode(fileUpload.getFileName(), "utf-8"));
            OutputStream os = response.getOutputStream();
            BufferedOutputStream bos = new BufferedOutputStream(os);
            InputStream is = new FileInputStream(fileUpload.getFilePath());
            BufferedInputStream bis = new BufferedInputStream(is);
            byte[] buffer = new byte[1024];
            int len;
            while((len = bis.read(buffer)) != -1) {
                bos.write(buffer, 0, len);
            }
            if(bos != null) {
                bos.close();
            }
            if(bis != null) {
                bis.close();
            }
            if(is != null) {
                is.close();
            }
            if(os != null) {
                os.close();
            }
        }
    }

下载excel文件的格式为：

String encoding = System.getProperty("file.encoding");
    response.setContentType("application/vnd.ms-excel;charset="+encoding); 
    response.setHeader("Content-Disposition", "attachment;filename="+URLEncoder.encode(fileName,encoding));