最近作了个领取微信卡券的小程序,看了不少文档资料以及花了不少时间才算搞定的,不过也算是好事多磨,这边记录分享一下,也算给一点提高。javascript
1、开发前准备前端
1:申请 微信公众号 和 微信小程序,这是两个不一样的东西,都须要单独申请、不一样的账号;java
2:微信公众号须要开通微信卡券的功能;json
3:在微信公众号里面去绑定微信小程序;小程序
4:申请微信开放平台,并将微信公众号 和 微信小程序绑定到该开放平台。(注:绑定到开发平台下的做用只是为了获取unionid,由于同一用户在 微信公众号 和 小程序下得到的openid是不同的,若是微信公众号 和 小程序都须要领取卡券,则最好经过unionid来跟踪用户;若是你只是开发微信小程序的领取卡券,则彻底能够忽略第4点,博主本人也没有去绑定到微信开放平台,感受步骤好多,特别麻烦!)后端
2、开始开发微信小程序
1:获取微信卡券api
https://mp.weixin.qq.com/wiki?t=resource/res_main&id=mp1451025272缓存
这边能够直接经过微信公众号提供的接口获取或者建立微信的卡券,此处不过多介绍,只是提一下这边要获取的access_token,网址以下https://mp.weixin.qq.com/wiki?t=resource/res_main&id=mp1421140183,代码直接以下:服务器
private static String grantType = "client_credential"; public static String appId = ""; //微信公众号appid public static String secret = ""; //微信公众号密钥 public static AccessToken token = null; //微信公众号的accessToken对象,因为请求次数有限制,这里使用全局静态变量保存起来 public static AccessToken getToken() throws WeixinException, JsonParseException, JsonMappingException, IOException{ if(token == null || token.getExpires_in() < System.currentTimeMillis()){ //拼接参数 String param = "?grant_type=" + grantType + "&appid=" + appId + "&secret=" + secret; //建立请求对象 HttpsClient http = new HttpsClient(); //调用获取access_token接口 Response res = http.get("https://api.weixin.qq.com/cgi-bin/token" + param); System.out.println(res.asString()); ObjectMapper mapper = new ObjectMapper(); token = mapper.readValue(res.asString(),AccessToken.class); } return token; }
其中须要jackson和weixin4j的jar包,比较广泛,请自行下载;而AccessToken对象也比较简单,就errcode、errmsg、access_token、expires_in这四个参数,比较简单,在文章结尾贴代码
2:升级微信卡券
其实这个步骤也能够省略,升级微信卡券的目的是能够直接从微信卡券跳转到对应的小程序,博主就偷懒了,直接跳过了这个步骤;
不过升级卡券也比较简单,就是调用调用微信公众号的更改微信卡券接口(URL:https://api.weixin.qq.com/card/update?access_token=TOKEN),添加几个字段,能够参考微信官方文档3.1,连接以下:https://mp.weixin.qq.com/cgi-bin/announce?action=getannouncement&key=1490190158&version=1&lang=zh_CN&platform=2
3:领取卡券
3.1:先获取openId
小程序端代码,经过调用wx.login获取code,再调用https://api.weixin.qq.com/sns/jscode2session接口获取openid,博主看到不少例子是直接从小程序端调用这个接口,但我事实中发现是行不通的,由于这个域名没法添加到小程序的request合法域名中,微信给的说明是不要在前端调用这个接口,须要经过后台,那没办法喽
wx.login({ success: function (res) { var service_url = 'https://???/???/weixin/api/login?code=' + res.code;//须要将服务器域名添加到小程序的request合法域名中,并且必须是https开头 wx.request({ url: l, data: {}, method: 'GET', success: function (res) { console.log(res); if (res.data != null && res.data != undefined && res.data != '') { wx.setStorageSync("openid", res.data.openid);//将获取的openid存到缓存中 } } }); } });
后端java代码
/** * 小程序后台登陆,向微信平台发送获取access_token请求,并返回openId * @param code * @return 用户凭证 * @throws WeixinException * @throws IOException * @throws JsonMappingException * @throws JsonParseException */ @RequestMapping("login") @ResponseBody public Map<String, Object> login(String code, HttpServletRequest request) throws WeixinException, JsonParseException, JsonMappingException, IOException { if (code == null || code.equals("")) { throw new WeixinException("invalid null, code is null."); } Map<String, Object> ret = new HashMap<String, Object>(); //拼接参数 String param = "?grant_type=" + grant_type + "&appid=" + appid + "&secret=" + secret + "&js_code=" + code; System.out.println("https://api.weixin.qq.com/sns/jscode2session" + param); //建立请求对象 HttpsClient http = new HttpsClient(); //调用获取access_token接口 Response res = http.get("https://api.weixin.qq.com/sns/jscode2session" + param); //根据请求结果断定,是否验证成功 JSONObject jsonObj = res.asJSONObject(); if (jsonObj != null) { Object errcode = jsonObj.get("errcode"); if (errcode != null) { //返回异常信息 throw new WeixinException(getCause(Integer.parseInt(errcode.toString()))); } ObjectMapper mapper = new ObjectMapper(); OAuthJsToken oauthJsToken = mapper.readValue(jsonObj.toJSONString(),OAuthJsToken.class); ret.put("openid", oauthJsToken.getOpenid()); } return ret; }
其中OAuthJsToken对象的字段为:openid、expires_in、session_key(会话密钥) ,在文章结尾贴代码;
3.2:生成领取卡券的签名,并调用wx.addCard方法领取卡券
这边写贴java后端代码
public static ApiTicket ticket = null;//使用全局静态变量存储ApiTicket对象,固然若是使用缓存框架保存固然更好,这边只是作一个简单示例 /** * @Description: 获取领取卡券获取签名等参数 * @param cardId:须要领取的卡券的cardId * @return * @throws WeixinException * @throws JsonParseException * @throws JsonMappingException * @throws IOException */ @RequestMapping("getCardSign") @ResponseBody public Map<String, String> getCardSign(String cardId) throws WeixinException, JsonParseException, JsonMappingException, IOException{ Map<String, String> ret = new HashMap<String, String>(); //先要获取api_ticket,因为请求api_ticket的接口访问有次数限制,因此最好将得到到的api_ticket保存到缓存中,这边作法比较简单,直接使用的静态变量 if(ticket == null || ticket.getExpires_in() < System.currentTimeMillis()){ //建立请求对象 HttpsClient http = new HttpsClient(); ObjectMapper mapper = new ObjectMapper(); AccessToken token = OpenApi.getToken();//这里获取的token就是最上方代码保存的微信公众号全局静态变量token //经过access_token调用获取api_ticket接口 Response res = http.get("https://api.weixin.qq.com/cgi-bin/ticket/getticket?access_token=" + token.getAccess_token() + "&type=wx_card"); System.out.println(res.asString()); ticket = mapper.readValue(res.asString(), ApiTicket.class); } ret = sign(ticket.getTicket(), cardId);//生成领取卡券须要的签名,并返回相关的参数 for (Map.Entry entry : ret.entrySet()) { System.out.println(entry.getKey() + ", " + entry.getValue()); } return ret; } /** * @Description: 生成卡券须要的签名并返回参数 * @param api_ticket: * @param cardId:须要领取的卡券的cardId * @return */ public static Map<String, String> sign(String api_ticket, String cardId) { Map<String, String> ret = new HashMap<String, String>(); String nonce_str = create_nonce_str(); String timestamp = create_timestamp(); String signature = ""; String param[] = new String[4]; param[0] = nonce_str; param[1] = timestamp; param[2] = api_ticket; param[3] = cardId; Arrays.sort(param);//对参数的value值进行字符串的字典序排序 StringBuilder sb = new StringBuilder(); for(String b : param){ sb.append(b); } System.out.println(sb); //对上面拼接的字符串进行sha1加密,获得signature try{ MessageDigest crypt = MessageDigest.getInstance("SHA-1"); crypt.reset(); crypt.update(sb.toString().getBytes("UTF-8")); signature = byteToHex(crypt.digest()); }catch (NoSuchAlgorithmException e){ e.printStackTrace(); }catch (UnsupportedEncodingException e){ e.printStackTrace(); } //返回领取卡券须要的参数,其中nonceStr和timestamp必须和签名中的保持一致 ret.put("card_id", cardId); ret.put("api_ticket", api_ticket); ret.put("nonceStr", nonce_str); ret.put("timestamp", timestamp); ret.put("signature", signature); return ret; }
其中ApiTicket对象的属性有:errcode、errmsg、ticket、expires_in,在文章结尾贴出该代码
再贴小程序端代码
var that = this; var service_url = 'https://???/???/weixin/api/getCardSign?cardId=' + cardId;//须要将服务器域名添加到小程序的request合法域名中,并且必须是https开头 wx.request({ url: service_url, data: {}, method: 'GET', success: function (res) { console.log(res); wx.addCard({ cardList: [{ cardId: that.data.cardId, cardExt: '{"code":"","openid":"","timestamp":' + res.data.timestamp + ',"nonce_str":"' + res.data.nonceStr + '","signature":"' + res.data.signature + '"}' }],//这里须要注意的是cardExt参数的value值是 String类型,不要使用对象发送;另外openid若是在建立优惠券的时候没有指定,则这边为空,千万不要填写当前用户的openid success: function (result) { console.log(res); wx.showToast({ title: '领取成功', icon: 'success', duration: 2000 }); }, fail: function (res) { console.log('领取失败'); console.log(res); } }) } });
ok,若是领取成功,能够直接到微信卡包里面查看。下面贴出AccessToken、ApiTicket、OAuthJsToken的java模型代码
public class BaseResponse { private int errcode; private String errmsg; public int getErrcode() { return errcode; } public void setErrcode(int errcode) { this.errcode = errcode; } public String getErrmsg() { return errmsg; } public void setErrmsg(String errmsg) { this.errmsg = errmsg; } } public class AccessToken extends BaseResponse{ private String access_token; private long expires_in; public String getAccess_token() { return access_token; } public void setAccess_token(String access_token) { this.access_token = access_token; } public long getExpires_in() { return expires_in; } public void setExpires_in(long expires_in) { this.expires_in = System.currentTimeMillis() + (expires_in - 100) * 1000;//原expires_in是有效时长,好比:7200,现改成过时的时间戳 } } public class ApiTicket extends BaseResponse{ private String ticket; private long expires_in; public String getTicket() { return ticket; } public void setTicket(String ticket) { this.ticket = ticket; } public long getExpires_in() { return expires_in; } public void setExpires_in(long expires_in) { this.expires_in = System.currentTimeMillis() + (expires_in - 100) * 1000;//原expires_in是有效时长,好比:7200,现改成过时的时间戳 } } public class OAuthJsToken { private String openid; //用户惟一标识 private int expires_in = 7200; //凭证有效时间,单位:秒 private String session_key; //会话密匙 private long exprexpiredTime; //过时时间 public String getOpenid() { return openid; } public void setOpenid(String openid) { this.openid = openid; } public int getExpires_in() { return expires_in; } public void setExpires_in(int expires_in) { this.expires_in = expires_in; this.exprexpiredTime = System.currentTimeMillis() + expires_in * 1000; } public String getSession_key() { return session_key; } public void setSession_key(String session_key) { this.session_key = session_key; } public long getExprexpiredTime() { return exprexpiredTime; } public void setExprexpiredTime(long exprexpiredTime) { this.exprexpiredTime = exprexpiredTime; } /** * 判断用户凭证是否过时 * * @return 过时返回 true,不然返回false */ public boolean isExprexpired() { return System.currentTimeMillis() >= this.exprexpiredTime; } }