思路
1.第一次获取放设置过期时间放map
2.下次从map中获取，如果如果为空就请求微信api. 如果不为空，就拿上次存放的过期时间和现在时间做比对，如果过期时间早于当前时间，就重新获取。
代码
protected synchronized AccessToken getAccessToken() { AccessToken accessToken = (AccessToken)tokenMap.get(this.appid); Long now = (new Date()).getTime(); if (accessToken == null || now > accessToken.getExpiresTimestemp()) { accessToken = WechatUtils.getAccessToken(this.appid, this.secret); tokenMap.put(this.appid, accessToken); logger.info("new accessToken"); } return accessToken; } public static AccessToken getAccessToken(String appid, String secret) { if (appid != null && secret != null) { ClientConfig config = new DefaultClientConfig(); Client client = Client.create(config); WebResource cosmsservice = client.resource("https://api.weixin.qq.com/cgi-bin/token"); ClientResponse clientResponse = (ClientResponse)cosmsservice.queryParam("grant_type", "client_credential").queryParam("appid", appid).queryParam("secret", secret).get(ClientResponse.class); if (clientResponse.getStatus() != 200) { throw new IllegalStateException("status error:" + clientResponse.getStatus()); } else { Map result = (Map)(new Gson()).fromJson((String)clientResponse.getEntity(String.class), Map.class); if (result.get("errcode") != null) { throw new WechatAccessException(result.get("errcode") + "", result.get("errmsg") + ""); } else { long now = (new Date()).getTime(); return new AccessToken((String)result.get("access_token"), ((Double)result.get("expires_in")).longValue() * 1000L + now); } } } else { throw new IllegalArgumentException("appid or secret was null."); } }
