springboot 环境+文件上传与文件下载功能。

「爱情、让人受尽委屈。」 2022-12-30 13:33 166阅读 0赞

最近。搭建个网站需要用到文件的上传和下载功能

废话少说，直接粘源码

**文件上传**  
前端  
多文件上传 上传图片为12张

<form action="/upload"  class="form-horizontal"  method="post" 
       
      enctype="multipart/form-data">
     上传图片个数为12张：<input type="file"  multiple name="picture">
     </form>

上传的图片的路径 保存到数据库，前端查数据库回显图片

//上传图片
        @ResponseBody
        @PostMapping("/upload") //前端以二进制流的形式发送，后端以二进制流接收
        public ModelAndView upload( @RequestParam("picture") MultipartFile[] file,String username ,String showflay) throws IOException { 
            ModelAndView mv = new ModelAndView();
            List  list= new ArrayList();
            LovePPlus lovePPlus = new LovePPlus();
            LoveP loveP = new LoveP();
            logger.warn("本次文件上传数量为----------"+String.valueOf(file.length));
            for (int i = 0; i < file.length; i++) { 
                if (!file[i].isEmpty() && file.length >= 12 && file.length <13) { 
                    //获取上传文件名
                    String filename = file[i].getOriginalFilename();
    
                    if ((filename).contains(".jpeg")||(filename).contains(".JPEG")||
                            (filename).contains(".jpg")||(filename).contains(".JPG")||
                            (filename).contains(".PNG")||(filename).contains(".png")) { 
                    }else{ 
                        System.out.println("文件上传失败");
                        mv.addObject("errmsg", "文件上传格式不支持");
                        mv.addObject("path", "lovep");
                        mv.setViewName("perror");
                        return mv;
                    }
                        //Target上传路径
                        //String filepath = ResourceUtils.getURL("classpath:").getPath() + "static/image/";
                        String filepath = "/lczze/net/image/";
                        //随机字符串
                        String RandomS = RandomUtil.generateStr(8);
                        //上传路径 + 文件名
                        File dest = new File(filepath + RandomS + ".png");
                        //文件上传
                        file[i].transferTo(dest);
                        logger.info("文件上传成功啦----------" + filepath + RandomS);
                        //测试回显路径
                        String pathimg = "http://lovenet.lczze.cn/" + RandomS + ".png";
                        //图片显示路径保存到集合，保存到数据库
                        list.add(pathimg);
                        logger.warn(pathimg + "----访问图片地址----------");
                        mv.addObject("sucmsg", "文件上传成功");
    
                        if (showflay.equals("1") && showflay != null){ 
                            //重定向 查询显示的照片墙
                            mv.setViewName("redirect:/lovep");
                        }
    
                } else { 
                    System.out.println("文件上传失败");
                    mv.addObject("errmsg", "请按规定的文件数量，您上传的文件数量为：" +file.length);
                    mv.addObject("path", "lovep");
                    mv.setViewName("perror");
                    return mv;
                }
            }
            logger.warn(String.valueOf(list)+"--------list集合内容");
            lovePPlus.setOneP((String) list.get(0));
            lovePPlus.setTwoP((String) list.get(1));
            lovePPlus.setThreeP((String) list.get(2));
            lovePPlus.setFourP((String) list.get(3));
            lovePPlus.setFiveP((String) list.get(4));
            lovePPlus.setSixP((String) list.get(5));
            lovePPlus.setSevenP((String) list.get(6));
            lovePPlus.setEightP((String) list.get(7));
            lovePPlus.setNineP((String) list.get(8));
            lovePPlus.setTenP((String) list.get(9));
            lovePPlus.setElevenP((String) list.get(10));
            lovePPlus.setTwelveP((String) list.get(11));
            //添加详情图片
            lovePPlusService.addRItem(lovePPlus);
            //拿到详情图片id；根据oneP 查询出当前字段对应的id
            LovePPlus onePId = lovePPlusService.getOnePId(lovePPlus);
    
            //是否显示图片
            loveP.setShowflay(Integer.parseInt(showflay));
            //拿到lovepplus id
            loveP.setPlus_id(onePId.getId());
            //拿到lovepplus表第一张图片
            loveP.setPicture((String) list.get(0));
            //接收前端用户名
            loveP.setUsername(username);
            loveP.setCteateTime(new Date());
            //创建照片墙主页
            lovePService.CreatePIndex(loveP);
    
            if (showflay.equals("0") && showflay != null){ 
                mv.addObject("pathlink","http://lovenet.lczze.cn/lpicture/"+onePId.getId());
                mv.addObject("path", "lovep");
                mv.setViewName("showlink");
            }
            return mv;
        }

**文件下载**

简单演示

<!DOCTYPE html >
    <html xmlns:th="http://www.thymeleaf.org">
    <html>
    <head>
        <meta charset="UTF-8">
    </head>
    <body>
    <form class="form-signin" th:action="@{/employee/File/download}" method="post">
        <p><h1>下载文件</h1></p>
        <p><h2>1.png</h2></p>
        
        <input type="text" name="fileN" value="201810251435.zip">
        <p><input type="submit" value="下载"/></p>
        <p style="color: red" th:text="${result}"   th:if="${not #strings.isEmpty(result)}"></p>
    </form>
    </body>
    </html>

文件下载后端代码

@PostMapping("/employee/File/download")
        public String  testDownload(HttpServletResponse response , Model model,String fileN) { 
            //待下载文件名
            String fileName = fileN;
            System.out.println(fileName+"---------------");
            //设置为png格式的文件
    // response.setHeader("content-type", "image/png");
            response.setContentType("application/octet-stream");
            response.setHeader("Content-Disposition", "attachment; filename=" + fileName);
            byte[] buff = new byte[1024];
            //创建缓冲输入流
            BufferedInputStream bis = null;
            OutputStream outputStream = null;
    
            try { 
                outputStream = response.getOutputStream();
    
                //这个路径为待下载文件的路径
                bis = new BufferedInputStream(new FileInputStream(new File("D:/lczze/net/image/" + fileName )));
                int read = bis.read(buff);
    
                //通过while循环写入到指定了的文件夹中
                while (read != -1) { 
                    outputStream.write(buff, 0, buff.length);
                    outputStream.flush();
                    read = bis.read(buff);
                }
            } catch ( IOException e ) { 
                e.printStackTrace();
                //出现异常返回给页面失败的信息
                model.addAttribute("result","下载失败");
            } finally { 
                if (bis != null) { 
                    try { 
                        bis.close();
                    } catch (IOException e) { 
                        e.printStackTrace();
                    }
                }
                if (outputStream != null) { 
                    try { 
                        outputStream.close();
                    } catch (IOException e) { 
                        e.printStackTrace();
                    }
                }
            }
            //成功后返回成功信息
            model.addAttribute("result","下载成功");
            System.out.println("下载成功...........................");
            return "employee/EmployeeDownloadFile";
        }