微信上传永久图片素材并获取mediaId

 public String uploadFile(String URL, String filePath, String type) throws Exception {
        File file = new File(filePath);
        if (!file.exists() || !file.isFile()) {
            throw new IOException("文件不存在！");
        }
 
        String url = URL.replace("ACCESS_TOKEN", TokenThread.accessToken.getToken()).replace("TYPE", type);
        URL urlObj = new URL(url);
 
        // 创建Http连接
        HttpURLConnection conn = (HttpURLConnection) urlObj.openConnection();
        conn.setRequestMethod("POST");
        conn.setDoInput(true);
        conn.setDoOutput(true);
        conn.setUseCaches(false);   // 使用post提交需要设置忽略缓存
 
        //消息请求头信息
        conn.setRequestProperty("Connection", "Keep-Alive");
        conn.setRequestProperty("Charset", "UTF-8");
 
        //设置边界
        String BOUNDARY = "----------" + System.currentTimeMillis();
        conn.setRequestProperty("Content-Type", "multipart/form-data;boundary=" + BOUNDARY);
 
        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\";filename=\"" + file.getName() + "\";filelength=\"" + file.length() + "\"\r\n");
        sb.append("Content-Type:application/octet-stream\r\n\r\n");
 
        byte[] head = sb.toString().getBytes("utf-8");
 
        // 创建输出流
        OutputStream out = new DataOutputStream(conn.getOutputStream());
        // 获得输出流表头
        out.write(head);
 
        //文件正文部分
        DataInputStream in = new DataInputStream(new FileInputStream(file));
        int bytes = 0;
        byte[] bufferOut = new byte[1024 * 1024 * 10]; // 10M
        while ((bytes = in.read(bufferOut)) != -1) {
            out.write(bufferOut, 0, bytes);
        }
        in.close();
 
        //结尾
        byte[] foot = ("\r\n--" + BOUNDARY + "--\r\n").getBytes("utf-8");
        out.write(foot);
        out.flush();
        out.close();
 
 
        // 获取响应
        StringBuffer buffer = new StringBuffer();
        BufferedReader reader = null;
        String result = null;
        try {
            reader = new BufferedReader(new InputStreamReader(conn.getInputStream()));
            String line = null;
            while ((line = reader.readLine()) != null) {
                buffer.append(line);
            }
            if (result == null) {
                result = buffer.toString();
            }
        } catch (IOException e) {
            e.printStackTrace();
        } finally {
            reader.close();
        }
        System.out.println(result);
        String mediaId = "";
        if (!type.equals("image")) {
        	mediaId = JSONObject.fromObject(result).getString(type + "_media_id");
        } else {
        	mediaId = JSONObject.fromObject(result).getString("media_id");
        }
        return mediaId;
    }

public static final String PERMANENT_UPLOAD_MATERIAL_URL = "https://api.weixin.qq.com/cgi-bin/material/add_material?access_token=ACCESS_TOKEN&type=TYPE";
String mediaId = util.uploadFile(PERMANENT_UPLOAD_MATERIAL_URL, "D:\\1.jpg" , "image");