將圖片上傳顯示瀏覽器

1.文件上傳，通過通道上傳文件

/**
     * 文件上傳
     * @param request
     * @return
     */
    @PostMapping("/uploadFile")
    @ResponseBody
    public String uploadFiles(@RequestParam("file") MultipartFile file , HttpServletRequest request) throws IOException {
        if (!file.isEmpty()) {
            String saveFileName = file.getOriginalFilename();
            //獲取當前路勁的地址
            String systemPath =System.getProperty("user.dir")+"/imageLibrary/";
            String fileName = new Date().getTime()+saveFileName;
            String saveFilePath = systemPath+ fileName;
            //創建文件夾
            File filePath1 = new File(systemPath);
            if (!filePath1.exists()) {
                filePath1.mkdirs();
            }
            //創建文件
            File filePath = new File(saveFilePath);
            if (!filePath.exists()) {
                filePath.createNewFile();
            }

            FileConfig.writeChange(saveFilePath,file);

            return fileName;

        } else {
            return "上傳失敗，因爲文件爲空.";
        }

    }

public static void writeChange(String path, MultipartFile file) {

        try {

            File file1 = new File(path);
            RandomAccessFile raf1 = new RandomAccessFile(file1, "rw");
            FileChannel fw = raf1.getChannel();
            ByteBuffer buffer = ByteBuffer.wrap(file.getBytes());
            fw.write(buffer);
            buffer.clear();
            fw.close();
            raf1.close();

        } catch (IOException e) {
            e.printStackTrace();
        }
    }

2.讀取文件並且顯示到瀏覽器

 public static void showLogo(String path, HttpServletResponse response){
        try {
            OutputStream os = response.getOutputStream();
            File file1 = new File(path);
            RandomAccessFile raf1 = new RandomAccessFile(file1, "r");
            FileChannel fw = raf1.getChannel();
            ByteBuffer buffer = ByteBuffer.allocate(500);
            while (true){
                buffer.clear();
                int len = fw.read(buffer);

                if (len == -1) {
                    break;
                }
                buffer.flip();
                //也可以通過buffer寫
                os.write(buffer.array());
                os.flush();
            }
            os.close();
            fw.close();
            raf1.close();
        } catch (IOException e) {
            e.printStackTrace();
        }
    }