java微信开发之上传下载多媒体文件

回复图片、音频、视频消息都是需要media_id的，这个是需要将多媒体文件上传到微信服务器才有的。

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：http://mp.weixin.qq.com/wiki/index.php?title=上传下载多媒体文件

上传下载多媒体文件的方法还是写到WeixinUtil.java中。

代码如下：import java.io.BufferedOutputStream;import java.io.BufferedReader;import java.io.DataInputStream;import java.io.DataOutputStream;import java.io.File;import java.io.FileInputStream;import java.io.FileOutputStream;import java.io.IOException;import java.io.InputStream;import java.io.InputStreamReader;import java.io.OutputStream;import java.net.HttpURLConnection;import java.net.MalformedURLException;import java.net.URL;import java.security.KeyManagementException;import java.security.NoSuchAlgorithmException;import java.security.NoSuchProviderException;import java.security.SecureRandom;import java.util.Calendar;import java.util.Date;import java.util.HashMap;import java.util.Map; import javax.net.ssl.HttpsURLConnection;import javax.net.ssl.SSLContext;import javax.net.ssl.SSLSocketFactory;import javax.net.ssl.TrustManager; import net.sf.json.JSONObject; import org.apache.commons.lang.StringUtils;import org.apache.log4j.Logger; import com.company.project.model.menu.AccessToken;import com.company.project.model.menu.Menu; public class WeixinUtil { private static Logger log = Logger.getLogger(WeixinUtil.class); public final static String APPID = "wxb927d4280e6db674"; public final static String APP_SECRET = "21441e9f3226eee81e14380a768b6d1e"; // 获取access_token的接口地址（GET） 限200（次/天） public final static String access_token_url = "https://api.weixin.qq.com/cgi-bin/token?grant_type=client_credential&appid=APPID&secret=APPSECRET"; // 创建菜单 public final static String create_menu_url = "https://api.weixin.qq.com/cgi-bin/menu/create?access_token=ACCESS_TOKEN"; // 存放：1.token，2：获取token的时间,3.过期时间 public final static Map<String,Object> accessTokenMap = new HashMap<String,Object>(); /** * 发起https请求并获取结果 ** @param requestUrl 请求地址 * @param requestMethod 请求方式（GET、POST） * @param outputStr 提交的数据 * @return JSONObject(通过JSONObject.get(key)的方式获取json对象的属性值) */ public static JSONObject handleRequest(String requestUrl,String requestMethod,String outputStr) { JSONObject jsonObject = null;try {URL url = new URL(requestUrl);HttpsURLConnection conn = (HttpsURLConnection) url.openConnection();SSLContext ctx = SSLContext.getInstance("SSL", "SunJSSE");TrustManager[] tm = {new MyX509TrustManager()};ctx.init(null, tm, new SecureRandom());SSLSocketFactory sf = ctx.getSocketFactory();conn.setSSLSocketFactory(sf);conn.setDoInput(true);conn.setDoOutput(true);conn.setRequestMethod(requestMethod);conn.setUseCaches(false);if ("GET".equalsIgnoreCase(requestMethod)) {conn.connect();}if (StringUtils.isNotEmpty(outputStr)) {OutputStream out = conn.getOutputStream();out.write(outputStr.getBytes("utf-8"));out.close();}InputStream in = conn.getInputStream();BufferedReader br = new BufferedReader(new InputStreamReader(in,"utf-8"));StringBuffer buffer = new StringBuffer();String line = null;while ((line = br.readLine()) != null) {buffer.append(line);}in.close();conn.disconnect();jsonObject = JSONObject.fromObject(buffer.toString()); } catch (MalformedURLException e) {e.printStackTrace();log.error("URL错误！"); } catch (IOException e) {e.printStackTrace(); } catch (NoSuchAlgorithmException e) {e.printStackTrace(); } catch (NoSuchProviderException e) {e.printStackTrace(); } catch (KeyManagementException e) {e.printStackTrace(); } return jsonObject; }/** * 获取access_token * * @author qincd * @date Nov 6, 2014 9:56:43 AM */ public static AccessToken getAccessToken(String appid,String appSecret) { AccessToken at = new AccessToken(); // 每次获取access_token时，先从accessTokenMap获取，如果过期了就重新从微信获取 // 没有过期直接返回 // 从微信获取的token的有效期为2个小时 if (!accessTokenMap.isEmpty()) {Date getTokenTime = (Date) accessTokenMap.get("getTokenTime");Calendar c = Calendar.getInstance();c.setTime(getTokenTime);c.add(Calendar.HOUR_OF_DAY, 2);getTokenTime = c.getTime();if (getTokenTime.after(new Date())) {log.info("缓存中发现token未过期，直接从缓存中获取access_token");// token未过期，直接从缓存获取返回String token = (String) accessTokenMap.get("token");Integer expire = (Integer) accessTokenMap.get("expire");at.setToken(token);at.setExpiresIn(expire);return at;} } String requestUrl = access_token_url.replace("APPID", appid).replace("APPSECRET", appSecret);JSONObject object = handleRequest(requestUrl, "GET", null); String access_token = object.getString("access_token"); int expires_in = object.getInt("expires_in");log.info("naccess_token:" + access_token); log.info("nexpires_in:" + expires_in);at.setToken(access_token); at.setExpiresIn(expires_in);// 每次获取access_token后，存入accessTokenMap // 下次获取时，如果没有过期直接从accessTokenMap取。 accessTokenMap.put("getTokenTime", new Date()); accessTokenMap.put("token", access_token); accessTokenMap.put("expire", expires_in);return at; }/** * 创建菜单 * * @author qincd * @date Nov 6, 2014 9:56:36 AM */ public static boolean createMenu(Menu menu,String accessToken) { String requestUrl = create_menu_url.replace("ACCESS_TOKEN", accessToken); String menuJsonString = JSONObject.fromObject(menu).toString(); JSONObject jsonObject = handleRequest(requestUrl, "POST", menuJsonString); String errorCode = jsonObject.getString("errcode"); if (!"0".equals(errorCode)) {log.error(String.format("菜单创建失败！errorCode:%d,errorMsg:%s",jsonObject.getInt("errcode"),jsonObject.getString("errmsg")));return false; }log.info("菜单创建成功！");return true; }// 上传多媒体文件到微信服务器 public static final String upload_media_url = "http://file.api.weixin.qq.com/cgi-bin/media/upload?access_token=ACCESS_TOKEN&type=TYPE"; /** * 上传多媒体文件到微信服务器<br> * @see http://www.oschina.net/code/snippet_1029535_23824 * @see http://mp.weixin.qq.com/wiki/index.php?title=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，更多请关注小潘博客其它相关文章！