我在用java调用云开发HTTPAPI上传文件时，总返回400错误，麻烦大神帮忙看下问题出在哪？

import cn.hutool.json.JSONObject;
import com.dimon.cloud.commons.rest.ApiResponse;
import com.dimon.cloud.customize.feign.WechatApi;
import org.apache.http.client.HttpClient;
import org.apache.http.client.methods.HttpPost;
import org.apache.http.entity.mime.MultipartEntityBuilder;
import org.apache.http.impl.client.HttpClientBuilder;
import org.springframework.beans.factory.annotation.Autowired;
import org.springframework.web.bind.annotation.PostMapping;
import org.springframework.web.bind.annotation.RestController;
import org.springframework.web.multipart.MultipartFile;
 
import javax.validation.constraints.NotNull;
import java.io.IOException;
 
/**
 * @Author: He Zhigang
 * @Date: 2019/10/12 18:00
 * @Description:
 */
@RestController
public class BackendController {
 
    @Autowired
    String accessToken;
 
    @Autowired
    WechatApi wechatApi;
 
    @PostMapping("/upload/prod/img")
    public ApiResponse uploadFile(@NotNull MultipartFile file) throws IOException {
        String dir = "p_cust/prod/img/";
        String path = dir + file.getOriginalFilename();
        JSONObject reqBody = new JSONObject();
        reqBody.put("env", "dev-4cs4fs");
        reqBody.put("path", path);
        JSONObject respJson = wechatApi.uploadFile(accessToken, reqBody);
        String url = respJson.getStr("url");
 
//        HttpResponse httpResponse = HttpRequest.post(url)
//                .contentType("multipart/form-data")
//                .header("Content-Type", "multipart/form-data")
//                .form("key", path)
//                .form("Signature", respJson.getStr("authorization"))
//                .form("x-cos-security-token", respJson.getStr("token"))
//                .form("x-cos-meta-fileid", respJson.getStr("cos_file_id"))
//                .form("file", file)
//                .execute();
        HttpClient httpClient = HttpClientBuilder.create().build();
        HttpPost httpPost = new HttpPost(url);
        httpPost.setHeader("Content-Type", "multipart/form-data");
 
        MultipartEntityBuilder builder = MultipartEntityBuilder.create();
        builder.addBinaryBody("file", file.getBytes())
                .addTextBody("key", path)
                .addTextBody("Signature", respJson.getStr("authorization"))
                .addTextBody("x-cos-security-token", respJson.getStr("token"))
                .addTextBody("x-cos-meta-fileid", respJson.getStr("cos_file_id"));
        httpPost.setEntity(builder.build());
        org.apache.http.HttpResponse res = httpClient.execute(httpPost);
        return ApiResponse.ok().setBody(res);
    }
 
 
 
}

上面我用了两种不同的HTTP client 都是返回同样的错误。