java 通过url下载文件到浏览器

我就是我 2023-02-22 15:53 26阅读 0赞

> 前端传来url地址与文件名，下载文件到浏览器

*  代码 (这里模拟，直接在代码里写了url,可以拼接在url后进行截取)
 *  请求接口
    
        @GetMapping("/findOperatorBarVO2")
          @ApiOperation(value = "下载")
          public void findOperatorCharBar2(HttpServletResponse response)throws IOException{ 
              toDownload(response);
          }
 *  下载方法
    
        public static void toDownload( HttpServletResponse response)  { 
              ServletOutputStream out = null;
              InputStream inputStream = null;
        
              try { 
                  //路径
                  String path = "http://10.202.61.66:11111/KEDFSFile/M00/00/1E/Cso9Ql7Z61CAZtQcAAAGqKgzHds335.txt";
                  // 取得文件的后缀名。
                  String ext = path.substring(path.lastIndexOf(".") + 1).toLowerCase();
                  //文件名
                  String pdfName = "问题."+ext;
                  // 获取外部文件流
                  URL url = new URL(path);
                  HttpURLConnection conn = (HttpURLConnection) url.openConnection();
                  conn.setConnectTimeout(3 * 1000);
                  //防止屏蔽程序抓取而返回403错误
                  conn.setRequestProperty("User-Agent", "Mozilla/4.0 (compatible; MSIE 5.0; Windows NT; DigExt)");
                  inputStream = conn.getInputStream();
                  /** * 输出文件到浏览器 */
                  int len = 0;
                  // 输出 下载的响应头，如果下载的文件是中文名，文件名需要经过url编码
                  response.setContentType("application/x-download");
                  response.setHeader("Content-Disposition", "attachment;filename=" + URLEncoder.encode(pdfName, "UTF-8"));
                  response.setHeader("Cache-Control", "no-cache");
                  out = response.getOutputStream();
                  byte[] buffer = new byte[1024];
                  while ((len = inputStream.read(buffer)) > 0) { 
                      out.write(buffer, 0, len);
                  }
                  out.flush();
              } catch (Exception e) { 
        
                  e.printStackTrace();
              } finally { 
                  if (inputStream != null) { 
                      try { 
                          inputStream.close();
                      } catch (Exception e) { 
                      }
                  }
                  if (out != null) { 
                      try { 
                          out.close();
                      } catch (Exception e) { 
                      }
                  }
              }
          }
 *  前端代码
    
        window.location.href = "http://localhost:9090/xx/evaOperator/findOperatorBarVO2";