//前端圖片是Base64字串形式傳遞圖片引數；需要用Base解密，寫入到本地磁碟中
public String upload(String string){
 
    解析圖片(Base64):
    response.setHeader("Access-Control-Allow-Origin","*");  // 第二個引數填寫允許跨域的域名稱，不建議直接寫 "*"
    response.setHeader("Access-Control-Allow-Headers", "X-Requested-With");
    response.setHeader("Access-Control-Allow-Methods", "PUT,POST,GET,DELETE,OPTIONS");
 
    
 
// 接收跨域的cookie
    response.setHeader("Access-Control-Allow-Credentials", "true");
    url = url.substring(url.indexOf(",")+1,url.length());
    String imagePath = null;
    BASE64Decoder decoder = new BASE64Decoder();
    String strName = null;
    String string2 = request.getScheme()+"://"+request.getServerName()+":"+request.getServerPort()+request.getContextPath();
    System.out.println(string2);
    
 
try {
        byte[] bytes = decoder.decodeBuffer(url);
        // 處理資料
        for (int i = 0; i < bytes.length; ++i) {
            if (bytes[i] < 0) {
                bytes[i] += 256;
            }
        }
        strName = UUID.randomUUID().toString();
        System.out.println(strName);
        imagePath 
 
= "E:/javaworkspace/project/rbApi/image/"+strName+".png";
        OutputStream out = new FileOutputStream(imagePath);
        out.write(bytes);
        out.flush();
        out.close();
    }catch (Exception e){
        e.printStackTrace();
    }
}
//springboot專案
//以@RequestParam("url") List<MultipartFile> url接收上傳圖片；寫入到本地磁碟中
//返回路徑是磁碟路徑，將磁碟路徑對映到外部靜態資源；訪問：專案路徑+對映路徑+檔名
@RequestMapping(value = "/uploadImage")
@ResponseBody
public PictureUrl upload(@RequestParam("url") List<MultipartFile> url, HttpServletRequest request, HttpServletResponse response){
    PictureUrl pictureUrl = new PictureUrl();
    String contentPath = request.getScheme()+"://"+request.getServerName()+":"+request.getServerPort()+request.getContextPath();
    try{
        if(url.size() == 0){
            pictureUrl.setStatusText("false");
        }else{
            OutputStream os = null;
            List<String> urlList = new ArrayList<>();
            for (MultipartFile file : url){
                String fileName = file.getOriginalFilename();
                String fileNam2 = UUID.randomUUID().toString();
                String imagePath = "E:/javaworkspace/project/rbApi/image/"+fileNam2+".png";
                File file1 = new File(imagePath);
                os = new FileOutputStream(file1);
                os.write(file.getBytes());
                //String imagePath2 = contentPath + "/showImage?id=" + fileNam2+".png";
                //String imagePath2 = upload + fileNam2+".png";
                String imagePath2 = contentPath+"/image/"+fileNam2+".png";
                urlList.add(imagePath2);
                System.out.println("檔案路徑："+imagePath2);
            }
            pictureUrl.setStatusText("ok");
            pictureUrl.setImageUrl(urlList);
            os.flush();
            os.close();
        }
 
    }catch (Exception e){
        e.printStackTrace();
        pictureUrl.setStatusText("false");
        return pictureUrl;
    }
     
    return pictureUrl;
 
}
//將圖片以二進位制的形式輸出，前端路徑可為:(專案路徑+方法+檔名)
 /**
 * 回顯圖片
 * @param id
 * @param response
 * @return
 */
@RequestMapping("/showImage")
@ResponseBody
public AjaxResult download(String id, HttpServletResponse response){
    try{
        response.setContentType("image/jpeg/jpg/png/gif/bmp/tiff/svg");
        String path ="E:/javaworkspace/project/rbApi/image/"+id;
        File file = new File(path);//括號裡引數為檔案圖片路徑
        if(file.exists()){   //如果檔案存在
            InputStream in = new FileInputStream(path);   //用該檔案建立一個輸入流
            OutputStream os = response.getOutputStream();  //建立輸出流
            byte[] b = new byte[1024];
            while( in.read(b)!= -1){
                os.write(b);
            }
            in.close();
            os.flush();
            os.close();
        }
        return null;
    }catch (Exception e){
        e.printStackTrace();
        return AjaxResult.build("false",null );
    }
}
 
//將磁碟檔案路徑對映為專案訪問路徑
@Configuration
public class WebMvcConfiguration implements WebMvcConfigurer {
    @Override
    public void addResourceHandlers(ResourceHandlerRegistry registry) {
        registry.addResourceHandler("/image/**").addResourceLocations("file:E:/javaworkspace/project/rbApi/image/");
    }
}