文件上传与下载

Thymeleaf 页面渲染

<form action="/" method="post"
 enctype="multipart/form-data">
    上传文件：
    <input type="file" name="file"/><br/>
    <input type="submit" value="上传"/>
</form>
<ul>
    <li th:each="file:${files}">
    <a th:href="${file}"><img th:src="${file}"/></a>
    </li>
</ul>

SpringMVC，使用Java7 New IO

    ...
    private final Path location = Paths.get("src/main/resources/files");

    @GetMapping
    public String show(Model model) throws IOException {
        if (!Files.exists(location)) Files.createDirectory(location);
        List<Path> files = Files.list(location)
                .map(location::relativize)
                .map(file -> Paths.get("files").resolve(file))
                .collect(Collectors.toList());
        model.addAttribute("files", files);
        return "index";
    }

    //上传
    @PostMapping("/upload")
    public String upload(HttpServletRequest request) throws IOException, ServletException {
        Part part = request.getPart("file");
        InputStream src = part.getInputStream();
        Path des = location.resolve(part.getSubmittedFileName());
        if (!Files.exists(des))
            Files.copy(src, des);
        return "redirect:/";
    }

    //下载
    @GetMapping("files/{filename:.+}")
    public void get(@PathVariable String filename, HttpServletResponse response) throws IOException {
        Path src = location.resolve(filename);
        if (Files.exists(src))
            Files.copy(src, response.getOutputStream());
    }
    ...