使用Retrofit2发送图像

Bitmap bitmap = BitmapFactory.decodeResource(getResources(), R.drawable.image);
ByteArrayOutputStream baos = new ByteArrayOutputStream();
bitmap.compress(Bitmap.CompressFormat.JPEG, 100, baos);
byte[] imageBytes = baos.toByteArray();
String base64Image = Base64.encodeToString(imageBytes, Base64.DEFAULT);

public interface ApiService {
    @POST("uploadImage")
    Call<ResponseBody> uploadImage(@Body RequestBody image);
}

Retrofit retrofit = new Retrofit.Builder()
        .baseUrl("https://api.example.com/")
        .addConverterFactory(GsonConverterFactory.create())
        .build();

ApiService apiService = retrofit.create(ApiService.class);

RequestBody requestBody = RequestBody.create(MediaType.parse("text/plain"), base64Image);

Call<ResponseBody> call = apiService.uploadImage(requestBody);
call.enqueue(new Callback<ResponseBody>() {
    @Override
    public void onResponse(Call<ResponseBody> call, Response<ResponseBody> response) {
        // 处理响应
    }

    @Override
    public void onFailure(Call<ResponseBody> call, Throwable t) {
        // 处理错误
    }
});