springboot业务功能实战（十五）以流的方式对文件上传下载

• java

  

   

    

     

    
    

     

      @Controller
     
    
   

    

     

    
    

     

      public class FileController {
     
    
   

    

     

    
    

     
 
     
    
   

    

     

    
    

     
    @RequestMapping(value = "/fileuploads")
     
    
   

    

     

    
    

     
    public String toFileUpload() {
     
    
   

    

     

    
    

     
        return "fileupload";
     
    
   

    

     

    
    

     

          }
     
    
   

    

     

    
    

     
 
     
    
   

    

     

    
    

     
    @RequestMapping(value = "/fileupload")
     
    
   

    

     

    
    

     
    public String fileUpload(@RequestParam(value = "file") List<MultipartFile> files, HttpServletRequest request) {
     
    
   

    

     

    
    

     
        String msg = "";
     
    
   

    

     

    
    

     
        // 判断文件是否上传
     
    
   

    

     

    
    

     
        if (!files.isEmpty()) {
     
    
   

    

     

    
    

     
            // 设置上传文件的保存目录
     
    
   

    

     

    
    

     
            String basePath = request.getServletContext().getRealPath("/upload/");
     
    
   

    

     

    
    

     
            // 判断文件目录是否存在
     
    
   

    

     

    
    

     

                  File uploadFile = new File(basePath);
     
    
   

    

     

    
    

     
            if (!uploadFile.exists()) {
     
    
   

    

     

    
    

     

                      uploadFile.mkdirs();
     
    
   

    

     

    
    

     

                  }
     
    
   

    

     

    
    

     
            for (MultipartFile file : files) {
     
    
   

    

     

    
    

     
                String originalFilename = file.getOriginalFilename();
     
    
   

    

     

    
    

     
                if (originalFilename != null && !originalFilename.equals("")) {
     
    
   

    

     

    
    

     
                    try {
     
    
   

    

     

    
    

     
                        // 对文件名做加UUID值处理
     
    
   

    

     

    
    

     

                              originalFilename = UUID.randomUUID() + "_" + originalFilename;
     
    
   

    

     

    
    

     

                              file.transferTo(new File(basePath + originalFilename));
     
    
   

    

     

    
    

     

                          } catch (IOException e) {
     
    
   

    

     

    
    

     

                              e.printStackTrace();
     
    
   

    

     

    
    

     

                              msg = "文件上传失败！";
     
    
   

    

     

    
    

     

                          }
     
    
   

    

     

    
    

     

                      } else {
     
    
   

    

     

    
    

     

                          msg = "上传的文件为空！";
     
    
   

    

     

    
    

     

                      }
     
    
   

    

     

    
    

     

                  }
     
    
   

    

     

    
    

     

                  msg = "文件上传成功！";
     
    
   

    

     

    
    

     

              } else {
     
    
   

    

     

    
    

     

                  msg = "没有文件被上传！";
     
    
   

    

     

    
    

     

              }
     
    
   

    

     

    
    

     

              request.setAttribute("msg", msg);
     
    
   

    

     

    
    

     
        return "chatroom";
     
    
   

    

     

    
    

     

          }
     
    
   

    

     

    
    

     
 
     
    
   

    

     

    
    

     
    @ExceptionHandler(MaxUploadSizeExceededException.class)
     
    
   

    

     

    
    

     
    public String handException(MaxUploadSizeExceededException e, HttpServletRequest request) {
     
    
   

    

     

    
    

     

      // System.out.println("我捕获了异常");
     
    
   

    

     

    
    

     

              request.setAttribute("msg", "文件超过了指定大小，上传失败！");
     
    
   

    

     

    
    

     
        return "fileupload";
     
    
   

    

     

    
    

     

          }
     
    
   

    

     

    
    

     
 
     
    
   

    

     

    
    

     
 
     
    
   

    

     

    
    

     
    @RequestMapping(value = "/filedownload")
     
    
   

    

     

    
    

     
    public String toFileDownload(HttpServletRequest request) {
     
    
   

    

     

    
    

     
        return "filedownload";
     
    
   

    

     

    
    

     

          }
     
    
   

    

     

    
    

     
 
     
    
   

    

     

    
    

     
    @RequestMapping(value = "/fileList")
     
    
   

    

     

    
    

     
    @ResponseBody
     
    
   

    

     

    
    

     
    public String fileList(HttpServletRequest request) {
     
    
   

    

     

    
    

     
        String baseDir = request.getServletContext().getRealPath("/upload");
     
    
   

    

     

    
    

     

              File baseFile = new File(baseDir);
     
    
   

    

     

    
    

     

              List<String> fileList = null;
     
    
   

    

     

    
    

     
        if (baseFile.exists()) {
     
    
   

    

     

    
    

     

                  File[] files = baseFile.listFiles();
     
    
   

    

     

    
    

     

                  fileList = new ArrayList<>(files.length);
     
    
   

    

     

    
    

     
            for (File file : files) {
     
    
   

    

     

    
    

     

                      fileList.add(file.getName());
     
    
   

    

     

    
    

     

                  }
     
    
   

    

     

    
    

     

              }
     
    
   

    

     

    
    

     

      // System.out.println(fileList.toString());
     
    
   

    

     

    
    

     
        String json = JSON.toJSONString(fileList);
     
    
   

    

     

    
    

     
        return json;
     
    
   

    

     

    
    

     

          }
     
    
   

    

     

    
    

     
 
     
    
   

    

     

    
    

     
 
     
    
   

    

     

    
    

     
    @RequestMapping(value = "/download")
     
    
   

    

     

    
    

     
    public ResponseEntity<byte[]> fileDownload(String filename, HttpServletRequest request) throws IOException {
     
    
   

    

     

    
    

     
        String path = request.getServletContext().getRealPath("/upload/");
     
    
   

    

     

    
    

     

              File file = new File(path + filename);
     
    
   

    

     

    
    

     

              System.out.println("转码前" + filename);
     
    
   

    

     

    
    

     

              filename = this.getFilename(request, filename);
     
    
   

    

     

    
    

     

              System.out.println("转码后" + filename);
     
    
   

    

     

    
    

     
        // 设置响应头通知浏览器下载
     
    
   

    

     

    
    

     

              HttpHeaders headers = new HttpHeaders();
     
    
   

    

     

    
    

     
        // 将对文件做的特殊处理还原
     
    
   

    

     

    
    

     

              filename = filename.substring(filename.indexOf("_") + 1);
     
    
   

    

     

    
    

     

              headers.setContentDispositionFormData("attachment", filename);
     
    
   

    

     

    
    

     

              headers.setContentType(MediaType.APPLICATION_OCTET_STREAM);
     
    
   

    

     

    
    

     
        return new ResponseEntity<byte[]>(FileUtils.readFileToByteArray(file), headers, HttpStatus.OK);
     
    
   

    

     

    
    

     

          }
     
    
   

    

     

    
    

     
 
     
    
   

    

     

    
    

     
    // 根据不同的浏览器进行编码设置，返回编码后的文件名
     
    
   

    

     

    
    

     
    public String getFilename(HttpServletRequest request, String filename) throws UnsupportedEncodingException {
     
    
   

    

     

    
    

     
        String[] IEBrowerKeyWords = {"MSIE", "Trident", "Edge"};
     
    
   

    

     

    
    

     
        String userAgent = request.getHeader("User-Agent");
     
    
   

    

     

    
    

     
        for (String keyword : IEBrowerKeyWords) {
     
    
   

    

     

    
    

     
            if (userAgent.contains(keyword)) {
     
    
   

    

     

    
    

     
                return URLEncoder.encode(filename, "UTF-8");
     
    
   

    

     

    
    

     

                  }
     
    
   

    

     

    
    

     

              }
     
    
   

    

     

    
    

     
        return new String(filename.getBytes("UTF-8"), "ISO-8859-1");
     
    
   

    

     

    
    

     

          }
     
    
   

    

     

    
    

     
 
     
    
   

    

     

    
    

     
 
     
    
   

    

     

    
    

     

      }
     
    
  
 

• js

  

   

    

     

    
    

     

      $(function(){
     
    
   

    

     

    
    

     
		var targer = $("#main2")
     
    
   

    

     

    
    

     

      		$.ajax({
     
    
   

    

     

    
    

     
			url: "fileList",
     
    
   

    

     

    
    

     
			dataType: "json",
     
    
   

    

     

    
    

     
			success: function (data) {
     
    
   

    

     

    
    

     
				for (var i in data) {
     
    
   

    

     

    
    

     
					var a = $("<a></a><br>").text(data[i].substring(data[i].indexOf("_")+1))
     
    
   

    

     

    
    

     

      					a.attr("href", "${pageContext.request.contextPath}/download?filename="+encodeURIComponent(data[i]))
     
    
   

    

     

    
    

     

      					targer.append(a)
     
    
   

    

     

    
    

     

      					alert(targer)
     
    
   

    

     

    
    

     

      				}
     
    
   

    

     

    
    

     

      			}
     
    
   

    

     

    
    

     

      		})
     
    
   

    

     

    
    

     

      	}
     
    
  
 

  

   

    

     

    
    

     

      function check() {
     
    
   

    

     

    
    

     
		var file = document.getElementById("file");
     
    
   

    

     

    
    

     
		if (file.value == "") {
     
    
   

    

     

    
    

     

      			alert("上传的文件为空")
     
    
   

    

     

    
    

     
			return false;
     
    
   

    

     

    
    

     

      		}
     
    
   

    

     

    
    

     
		return true;
     
    
   

    

     

    
    

     

      	}
     
    
  
 

• jsp

  

   

    

     

    
    

     

      <div id="main" style="width:500px; margin: 0 auto;">
     
    
   

    

     

    
    

     
				<form action="fileupload" method="post" enctype="multipart/form-data" onsubmit="return check()">
     
    
   

    

     

    
    

     
					<input type="file" name="file" id="file" multiple="multiple"><br>
     
    
   

    

     

    
    

     
					<input type="submit" value="上传">
     
    
   

    

     

    
    

     
				</form>
     
    
   

    

     

    
    

     
			</div>
     
    
   

    

     

    
    

     
 
     
    
   

    

     

    
    

     
			<div id="main2" style="width:500px; margin: 0 auto;">
     
    
   

    

     

    
    

     
 
     
    
   

    

     

    
    

     
			</div>
     
    
  
 

文章来源: baocl.blog.csdn.net，作者：小黄鸡1992，版权归原作者所有，如需转载，请联系作者。

原文链接：baocl.blog.csdn.net/article/details/101749711