```java
package com.utils;

import java.io.*;
import java.net.HttpURLConnection;
import java.net.URL;
import java.util.Base64;

public class UploadFile {
    private static final String boundary = "----WebKitFormBoundary0jkH3KeWg3pxZxJ5"; // 分隔不同字段的边界字符串

    /**
     * http上传文件抓方法
     * @param base64Code 文件base64编码
     * @return 上传成功的json字符串
     * @throws Exception Exception
     */
    public static String uploadFn(String base64Code,String port) throws Exception {
//        String path ="D:\\wx\\WeChat Files\\wxid_ma3xknryhe2i22\\FileStorage\\File\\2024-05\\11.txt";
//        try (BufferedReader br = new BufferedReader(new FileReader(path))) {
//            String line;
//            while ((line = br.readLine()) != null) {
//                base64Code = line;
//            }
//        } catch (IOException e) {
//            e.printStackTrace();
//        }

        // 初始化URL对象：
        URL url = new URL(port);
        // 打开连接并设置方法：
        HttpURLConnection httpURLConnection = (HttpURLConnection) url.openConnection();
        httpURLConnection.setRequestMethod("POST");
        // 设置其他请求头：
        //设置Content-Type以指示你正在发送多部分形式的数据，通常用于文件上传
        httpURLConnection.setRequestProperty("Content-Type", "multipart/form-data; boundary=" + boundary);
        // 开启输出流
        httpURLConnection.setDoOutput(true);
        DataOutputStream outputStream = new DataOutputStream(httpURLConnection.getOutputStream());
        // 添加参数：
        String fieldName = System.currentTimeMillis()+".png";
        setFileByBase64(outputStream, base64Code, fieldName);
        setParam(outputStream, "filename", fieldName); // 添加文本参数
        setParam(outputStream, "action", "uploadfile"); // 添加文本参数
        setParam(outputStream, "calltoken", "3979189c96de598a7c2e10433bb1885a"); // 添加文本参数
        setParam(outputStream, "jsontype", ""); // 添加文本参数
        setParam(outputStream, "userid", "23af16b1-1ca3-4054-bc20-71d425eb48da"); // 添加文本参数
        setParam(outputStream, "customercode", "2020"); // 添加文本参数
        // 结束多部分数据：
        outputStream.writeBytes("\r\n--" + boundary + "--\r\n");
        // 关闭流
        outputStream.flush();
        outputStream.close();
        // 读取响应
        int responseCode = httpURLConnection.getResponseCode();
        if (responseCode == HttpURLConnection.HTTP_OK) {
            // 处理成功的响应
            BufferedReader in = new BufferedReader(new InputStreamReader(httpURLConnection.getInputStream()));
            String inputLine;
            StringBuilder content = new StringBuilder();
            while ((inputLine = in.readLine()) != null) {
                content.append(inputLine);
            }
            in.close();
            return content.toString();
        } else {
            return "{}";
            // 处理错误情况
        }

    }

    /**
     * post 字符串参数
     *
     * @param outputStream 请求流
     * @param key 字段名
     * @param value 字段值
     * @throws Exception ioException
     */
    public static void setParam(DataOutputStream outputStream, String key, String value) throws Exception {
        outputStream.writeBytes("\r\n--" + boundary + "\r\n");
        outputStream.writeBytes("Content-Disposition: form-data; name=\"" + key + "\"\r\n\r\n");
        outputStream.writeBytes(value);
    }

    /**
     * post文件参数
     *
     * @param outputStream 请求流
     * @param path 文件物理地址
     * @throws Exception ioException
     */
    public  void setFile(DataOutputStream outputStream, String path) throws Exception {
        File file = new File(path);
        FileInputStream fis = new FileInputStream(file);
        byte[] fileBytes = new byte[(int) file.length()];
        fis.read(fileBytes);

        outputStream.writeBytes("\r\n--" + boundary + "\r\n");
        outputStream.writeBytes("Content-Disposition: form-data; name=\"upfile\"; filename=\"" + file.getName() + "\"\r\n");
        outputStream.writeBytes("Content-Type: application/octet-stream\r\n\r\n");
        outputStream.write(fileBytes);
    }

    /**
     * post文件参数
     *
     * @param outputStream 请求流
     * @param base64 文件base64编码
     * @param fieldName 文件名
     * @throws Exception ioException
     */
    public static void setFileByBase64(DataOutputStream outputStream, String base64, String fieldName) throws Exception {
        // base64解码转二进制
        byte[] decodedBytes = Base64.getDecoder().decode(base64);
        outputStream.writeBytes("\r\n--" + boundary + "\r\n");
        outputStream.writeBytes("Content-Disposition: form-data; name=\"upfile\"; filename=\"" + fieldName + "\"\r\n");
        outputStream.writeBytes("Content-Type: application/octet-stream\r\n\r\n");
        outputStream.write(decodedBytes);
    }
}