參考：https://blog.csdn.net/zmx729618/article/details/78038764
@PostMapping("/base64Upload")
public AppResult<String> uploadImage(String base64Data){
    log.info("==上傳圖片==");
    log.info("==接收到的資料=="+base64Data);


    String dataPrix = ""; //base64格式前頭
    String data = "";//實體部分資料
    if(base64Data==null||"".equals(base64Data)){
        return AppResultBuilder.buildFailedResult("上傳失敗，上傳圖片資料為空","401");
    }else {
        String [] d = base64Data.split("base64,");//將字串分成陣列
        if(d != null && d.length == 2){
            dataPrix = d[0];
            data = d[1];
        }else {
            return AppResultBuilder.buildFailedResult("上傳失敗，資料不合法","401");
        }
    }
    String suffix = "";//圖片字尾，用以識別哪種格式資料
    //data:image/jpeg;base64,base64編碼的jpeg圖片資料
    if("data:image/jpeg;".equalsIgnoreCase(dataPrix)){
        suffix = ".jpg";
    }else if("data:image/x-icon;".equalsIgnoreCase(dataPrix)){
        //data:image/x-icon;base64,base64編碼的icon圖片資料
        suffix = ".ico";
    }else if("data:image/gif;".equalsIgnoreCase(dataPrix)){
        //data:image/gif;base64,base64編碼的gif圖片資料
        suffix = ".gif";
    }else if("data:image/png;".equalsIgnoreCase(dataPrix)){
        //data:image/png;base64,base64編碼的png圖片資料
        suffix = ".png";
    }else {
        return AppResultBuilder.buildFailedResult("上傳圖片格式不合法","401");
    }
    String uuid = UUID.randomUUID().toString().replaceAll("-", "");
    String tempFileName=uuid+suffix;
    String imgFilePath = "G:\\Images\\"+tempFileName;//新生成的圖片
    BASE64Decoder decoder = new BASE64Decoder();
    try {
        //Base64解碼
        byte[] b = decoder.decodeBuffer(data);
        for(int i=0;i<b.length;++i) {
            if(b[i]<0) {
                //調整異常資料
                b[i]+=256;
            }
        }
        OutputStream out = new FileOutputStream(imgFilePath);
        out.write(b);
        out.flush();
        out.close();
        String imgurl="http://xxxxxxxx/"+tempFileName;
        //imageService.save(imgurl);
        return AppResultBuilder.buildSuccessResult(imgurl,"200");
    } catch (IOException e) {
        e.printStackTrace();
        return AppResultBuilder.buildFailedResult("上傳圖片失敗","401");
    }

}