将多媒体文件上传到微信服务器，以及从微信服务器下载文件，可以参考： 上传下载多媒体文件 * * @author qincd * @date Nov 6, 2014 4:11:22 PM */ public static JSONObject uploadMediaToWX(String filePath,String type,String accessToken) throws IOException{ File file = new File(filePath); if (!file.exists()) { log.error("文件不存在！"); return null; } String url = upload_media_url.replace("ACCESS_TOKEN", accessToken).replace("TYPE", type); URL urlObj = new URL(url); HttpURLConnection conn = (HttpURLConnection) urlObj.openConnection(); conn.setDoInput(true); conn.setDoOutput(true); conn.setUseCaches(false); 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); // 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("rn"); sb.append("Content-Disposition: form-data;name="file";filename="" + file.getName() + ""rn"); sb.append("Content-Type:application/octet-streamrnrn"); byte[] head = sb.toString().getBytes("utf-8"); // 获得输出流 OutputStream out = new DataOutputStream(conn.getOutputStream()); out.write(head); // 文件正文部分 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 = ("rn--" + BOUNDARY + "--rn").getBytes("utf-8");// 定义最后数据分隔线 out.write(foot); out.flush(); out.close(); /** * 读取服务器响应，必须读取,否则提交不成功 */ try { // 定义BufferedReader输入流来读取URL的响应 StringBuffer buffer = new StringBuffer(); BufferedReader reader = new BufferedReader(new InputStreamReader( conn.getInputStream())); String line = null; while ((line = reader.readLine()) != null) { buffer.append(line); } reader.close(); conn.disconnect(); return JSONObject.fromObject(buffer.toString()); } catch (Exception e) { log.error("发送POST请求出现异常！" + e); e.printStackTrace(); } return null; } public static final String download_media_url = "http://file.api.weixin.qq.com/cgi-bin/media/get?access_token=ACCESS_TOKEN&media_id=MEDIA_ID"; /** * 从微信服务器下载多媒体文件 * * @author qincd * @date Nov 6, 2014 4:32:12 PM */ public static String downloadMediaFromWx(String accessToken,String mediaId,String fileSavePath) throws IOException { if (StringUtils.isEmpty(accessToken) || StringUtils.isEmpty(mediaId)) return null; String requestUrl = download_media_url.replace("ACCESS_TOKEN", accessToken).replace("MEDIA_ID", mediaId); URL url = new URL(requestUrl); HttpURLConnection conn = (HttpURLConnection) url.openConnection(); conn.setRequestMethod("GET"); conn.setDoInput(true); conn.setDoOutput(true); InputStream in = conn.getInputStream(); File dir = new File(fileSavePath); if (!dir.exists()) { dir.mkdirs(); } if (!fileSavePath.endsWith("/")) { fileSavePath += "/"; } String ContentDisposition = conn.getHeaderField("Content-disposition"); String weixinServerFileName = ContentDisposition.substring(ContentDisposition.indexOf("filename")+10, ContentDisposition.length() -1); fileSavePath += weixinServerFileName; BufferedOutputStream bos = new BufferedOutputStream(new FileOutputStream(fileSavePath)); byte[] data = new byte[1024]; int len = -1; while ((len = in.read(data)) != -1) { bos.write(data,0,len); } bos.close(); in.close(); conn.disconnect(); return fileSavePath; }}
测试代码：
public class WeixinUtilTest { /** * * @author qincd * @date Nov 6, 2014 9:57:54 AM */ public static void main(String[] args) { // 1).获取access_token AccessToken accessToken = WeixinUtil.getAccessToken(WeixinUtil.APPID, WeixinUtil.APP_SECRET); String filePath = "C:\Users\qince\Pictures\壁纸20141029091612.jpg"; JSONObject uploadJsonObj = testUploadMedia(filePath,"image",accessToken.getToken()); if (uploadJsonObj == null) { System.out.println("上传图片失败"); return; } int errcode = 0; if (uploadJsonObj.containsKey("errcode")) { errcode = uploadJsonObj.getInt("errcode"); } if (errcode == 0) { System.out.println("图片上传成功"); String mediaId = uploadJsonObj.getString("media_id"); long createAt = uploadJsonObj.getLong("created_at"); System.out.println("--Details:"); System.out.println("media_id:" + mediaId); System.out.println("created_at:" + createAt); } else { System.out.println("图片上传失败！"); String errmsg = uploadJsonObj.getString("errmsg"); System.out.println("--Details:"); System.out.println("errcode:" + errcode); System.out.println("errmsg:" + errmsg); } String mediaId = "6W-UvSrQ2hkdSdVQJJXShwtFDPLfbGI1qnbNFy8weZyb9Jac2xxxcAUwt8p4sYPH"; String filepath = testDownloadMedia(accessToken.getToken(), mediaId, "d:/test"); System.out.println(filepath); } /** * 上传多媒体文件到微信 * * @author qincd * @date Nov 6, 2014 4:15:14 PM */ public static JSONObject testUploadMedia(String filePath,String type,String accessToken) { try { return WeixinUtil.uploadMediaToWX(filePath, type, accessToken); } catch (IOException e) { e.printStackTrace(); } return null; } /** * 从微信下载多媒体文件 * * @author qincd * @date Nov 6, 2014 4:56:25 PM */ public static String testDownloadMedia(String accessToken,String mediaId,String fileSaveDir) { try { return WeixinUtil.downloadMediaFromWx(accessToken, mediaId, fileSaveDir); } catch (IOException e) { e.printStackTrace(); } return null; }}以上就是java微信开发之上传下载多媒体文件的详细内容，更多请关注php中文网其它相关文章！
