备注：测试基于微信公众平台测试号编写，真实开发环境基本适用
微信公众号上传素材有很多分类，比如图片、视频等，也有永久素材和临时素材的分类，其实调用接口过程大同小异，方法是可以复用的，在这里不再多说，详细的分类描述可以参考微信开放平台的文档：
https://developers./doc/offiaccount/Asset_Management/New_temporary_materials.html
下面是上传素材的代码，这里以上传永久素材为例来实现。
@RequestMapping("/postslt")@ResponseBodypublic static String getsid(String[] args) throws KeyManagementException, NoSuchAlgorithmException, IOException{//获取accessString access_token = getaccess();try {File file = new File("文件地址");//上传素材String path = "https://api./cgi-bin/material/add_material?access_token=" + access_token + "&type=image";String result = connectHttpsByPost(path, null, file);return result;} catch (IOException e) {e.printStackTrace();} catch (NoSuchAlgorithmException e) {e.printStackTrace();} catch (NoSuchProviderException e) {e.printStackTrace();} catch (KeyManagementException e) {e.printStackTrace();}return null;}
/*** 上传文件方法*/public static String connectHttpsByPost(String path, String KK, File file) throws IOException, NoSuchAlgorithmException, NoSuchProviderException, KeyManagementException {URL urlObj = new URL(path);//连接HttpURLConnection con = (HttpURLConnection) urlObj.openConnection();String result = null;con.setDoInput(true);con.setDoOutput(true);con.setUseCaches(false); // post方式不能使用缓存// 设置请求头信息con.setRequestProperty("Connection", "Keep-Alive");con.setRequestProperty("Charset", "UTF-8");// 设置边界String BOUNDARY = "----------" + System.currentTimeMillis();con.setRequestProperty("Content-Type","multipart/form-data; boundary="+ BOUNDARY);// 请求正文信息// 第一部分：StringBuilder sb = new StringBuilder();sb.append("--"); // 必须多两道线sb.append(BOUNDARY);sb.append("\r\n");sb.append("Content-Disposition: form-data;name=\"media\";filelength=\"" + file.length() + "\";filename=\""+ file.getName() + "\"\r\n");sb.append("Content-Type:application/octet-stream\r\n\r\n");byte[] head = sb.toString().getBytes("utf-8");// 获得输出流OutputStream out = new DataOutputStream(con.getOutputStream());// 输出表头out.write(head);// 文件正文部分// 把文件已流文件的方式 推入到url中DataInputStream in = new DataInputStream(new FileInputStream(file));int bytes = 0;byte[] bufferOut = new byte[1024];while ((bytes = in.read(bufferOut)) != -1) {out.write(bufferOut, 0, bytes);}in.close();// 结尾部分byte[] foot = ("\r\n--" + BOUNDARY + "--\r\n").getBytes("utf-8");// 定义最后数据分隔线out.write(foot);out.flush();out.close();StringBuffer buffer = new StringBuffer();BufferedReader reader = null;try {// 定义BufferedReader输入流来读取URL的响应reader = new BufferedReader(new InputStreamReader(con.getInputStream()));String line = null;while ((line = reader.readLine()) != null) {buffer.append(line);}if (result == null) {result = buffer.toString();}} catch (IOException e) {System.out.println("发送POST请求出现异常！" + e);e.printStackTrace();} finally {if (reader != null) {reader.close();}}return result;}
这样就可以得到素材的media_id了。
参考链接：/u013791374/article/details/53258275
