抄这个 https://github.com/wechatpay-apiv3/wechatpay-go/blob/main/services/fileuploader/marketing_image_uploader.go

// Copyright 2021 Tencent Inc. All rights reserved.

package fileuploader


import (
	"context"
	"io"


	"github.com/wechatpay-apiv3/wechatpay-go/core"
	"github.com/wechatpay-apiv3/wechatpay-go/services"
)


// MarketingImageUploadResponse 图片上传API（营销专用）返回结果
type MarketingImageUploadResponse struct {
	MediaUrl *string `json:"media_url"` // revive:disable-line:var-naming
}


// MarketingImageUploader 图片上传API（营销专用）
//
// 通过本接口上传图片后可获得图片url地址。图片url可在微信支付营销相关的API使用，
// 包括商家券、代金券、支付有礼等。
// 接口文档地址：https://pay.weixin.qq.com/wiki/doc/apiv3/apis/chapter9_0_1.shtml
type MarketingImageUploader services.Service


// Upload 上传图片至微信支付营销系统
func (u *MarketingImageUploader) Upload(
	ctx context.Context, fileReader io.Reader, filename string, contentType string,
) (*MarketingImageUploadResponse, *core.APIResult, error) {
	result, err := (*baseFileUploader)(u).upload(
		ctx, "/v3/marketing/favor/media/image-upload", fileReader, filename, contentType, map[string]interface{}{},
	)
	if err != nil {
		return nil, result, err
	}


	var resp = new(MarketingImageUploadResponse)
	if err = core.UnMarshalResponse(result.Response, resp); err != nil {
		return nil, result, err
	}
	return resp, result, nil
}

@ApiOperation("上传电子发票文件")
@PostMapping("uploadFapiaoFile")
public Result uploadFapiaoFile() throws IOException, NoSuchAlgorithmException, NoSuchProviderException, SignatureException, InvalidKeyException {
    String url = wxPay.getDomain() + "/v3/new-tax-control-fapiao/fapiao-applications/upload-fapiao-file";
    HttpUrl parse = HttpUrl.parse(url);
    String path = "E:\\online-consultation\\处方.pdf";
    String sm3 = FileUtils.sm3(path);
    // String sm3 = FileUtils.sm3(path);
    log.info("SM3[{}]", sm3);

    JSONObject meta = new JSONObject();
    meta.put("file_type", "PDF");
    meta.put("digest", sm3);
    meta.put("digest_algorithm", "SM3");


    String signatureString = WxSignatureUtil.getSignatureString("POST", parse, meta.toString());
    log.info("signature[{}]", signatureString);
    MultipartBody multipartBody = new MultipartBody.Builder()
            .setType(MultipartBody.FORM)
            .addFormDataPart("meta", "meta", RequestBody.create(MediaType.parse("application/json"), meta.toString()))
            .addFormDataPart("file", "file", RequestBody.create(new File(path), MediaType.parse("pdf/plain")))

            .build();
    OkHttpClient client = new OkHttpClient();
    Request build = new Request.Builder()
            .addHeader("Content-Type", "multipart/form-data")
            .addHeader("Authorization", signatureString)
            .addHeader("Accept", "application/json")
            .url(url)
            .post(multipartBody)
            .build();
    Response response = client.newCall(build).execute();
    ResponseBody responseBody = response.body();
    String string = responseBody.string();
    return Result.ok(string);
}
public static String sm3(String path) {
    Security.addProvider(new org.bouncycastle.jce.provider.BouncyCastleProvider());
    try (FileInputStream fis = new FileInputStream(path);
         ByteArrayOutputStream baos = new ByteArrayOutputStream()) {
        byte[] buffer = new byte[1024];
        int bytesRead;
        while ((bytesRead = fis.read(buffer)) != -1) {
            baos.write(buffer, 0, bytesRead);
        }
        SM3.Digest sm3 = new SM3.Digest();
        sm3.update(baos.toByteArray());
        byte[] digest = sm3.digest();
        return Hex.toHexString(digest);
    } catch (Exception e) {
        throw new RuntimeException(e);
    }
}
@Slf4j
public class WxSignatureUtil {
    private static String serial = "";
    private static String mchid = "";

    public static String getSignatureString(String method, HttpUrl url, String body) throws UnsupportedEncodingException, NoSuchAlgorithmException, SignatureException, InvalidKeyException {
        String nonceStr = RandomStrUtils.getRandomString(32);
        long timestamp = System.currentTimeMillis() / 1000;
        String message = buildMessage(method, url, timestamp, nonceStr, body);
        String signature = sign(message.getBytes("utf-8"));
        log.info("签名值:[{}]", signature);
        return "WECHATPAY2-SHA256-RSA2048 mchid=\"" + mchid + "\","
                + "nonce_str=\"" + nonceStr + "\","
                + "timestamp=\"" + timestamp + "\","
                + "serial_no=\"" + serial + "\","
                + "signature=\"" + signature + "\"";
    }

    public static String sign(byte[] message) throws NoSuchAlgorithmException, SignatureException, InvalidKeyException {
        Signature sign = Signature.getInstance("SHA256withRSA");
        InputStream resourceAsStream = WxSignatureUtil.class.getClassLoader().getResourceAsStream("apiclient_key.pem");
        sign.initSign(PemUtil.loadPrivateKey(resourceAsStream));
        sign.update(message);
        return Base64.getEncoder().encodeToString(sign.sign());
    }

    public static String buildMessage(String method, HttpUrl url, long timestamp, String nonceStr, String body) {
        String canonicalUrl = url.encodedPath();
        if (url.encodedQuery() != null) {
            canonicalUrl += "?" + url.encodedQuery();
        }
        StringBuilder sb = new StringBuilder(method + "\n"
                + canonicalUrl + "\n"
                + timestamp + "\n"
                + nonceStr + "\n");
        if (!StringUtils.isEmpty(body)) {
            sb.append(body + "\n");
        } else {
            sb.append(""+"\n");
        }
        String str = sb.toString();
        log.info("构造签名体:[{}]", str);
        return str;
    }

}

{

"code": "SIGN_ERROR",

"detail": {

"detail": {

"issue": "sign not match"

},

"field": "signature",

"location": "authorization",

"sign_information": {

"method": "POST",

"sign_message_length": 116,

"truncated_sign_message": "POST\n/v3/new-tax-control-fapiao/fapiao-applications/upload-fapiao-file\n1722331061\nHp19Fkd3BaYXp3rMXSjzA88wJCT5GE32\n\n",

"url": "/v3/new-tax-control-fapiao/fapiao-applications/upload-fapiao-file"

}

},

"message": "错误的签名，验签失败"

}我也遇到这种情况，兄弟你解决了吗