微信公众号开发-获取access_token

Model——AccessToken

//微信通用接口凭证
public class AccessToken {
    // 获取到的凭证
    private String token;
    // 获取到ticket
    private String ticket;
    // 凭证有效时间，单位：秒
    private int expiresIn;
    // 添加时间
    private long addTime;
}

获取AccessToken外部调用方法getAccessToken，

public final static String access_token_url = "https://api.weixin.qq.com/cgi-bin/token?grant_type=client_credential&appid=APPID&secret=APPSECRET";

public static String getAccessToken(String appId,String secret) {
    AccessToken accessTocken = getAccessToken(appId, secret,System.currentTimeMillis()/1000);//毫秒转秒
    return accessTocken.getToken();
}


public static AccessToken getAccessToken(String appid, String appsecret, long currentTime) {
    AccessToken tockenTicketCache = getTokenTicket(TOKEN);//从缓存中获取
    AccessToken accessToken = null;
    if (tockenTicketCache != null && 
        (currentTime - tockenTicketCache.getAddTime() <= tockenTicketCache.getExpiresIn() )) {
        // 缓存存在并且没过期
        log.info("==========缓存中token已获取时长为：" + (currentTime - tockenTicketCache.getAddTime()) + "秒，可以重新使用");
            return tockenTicketCache;
        }
    JSONObject jsonObject = httpRequest(requestUrl, "GET", null);
    if (null != jsonObject) {//重新请求获取
        accessToken = new AccessToken();
        accessToken.setToken(jsonObject.getString("access_token"));
        // 正常过期时间是7200秒，此处设置3600秒读取一次
        accessToken.setExpiresIn(jsonObject.getIntValue("expires_in") / 2);
        log.info("==========tocket缓存过期时间为:" + accessToken.getExpiresIn() + "秒");
        accessToken.setAddTime(currentTime);
        updateAccessToken(TOKEN, accessToken);//更新缓存
    }
}


    /**
     * 从缓存中读取token或者ticket
     * 
     * @return
     */
    private static AccessToken getTokenTicket(String key) {
        if (TOKEN_TICKET_CACHE != null && TOKEN_TICKET_CACHE.get(key) != null) {
            log.info("==========从缓存中获取到了" + key + "成功===============");
            return TOKEN_TICKET_CACHE.get(key);
        }
        return null;
    }
// token,ticket缓存，
//类加载的时候（第一次访问），这个类中所有静态成员就会被加载在静态存储区，同时存储在静态变量区域的成员一旦创建，直到程序退出才会被回收。
public static Map<String, AccessToken> TOKEN_TICKET_CACHE = new HashMap<String, AccessToken>();
// 获取access_token的接口地址（GET） 限2000（次/天）

    /**
     * 更新缓存中token或者ticket
     * 
     * @return
     */
    private static void updateAccessToken(String key, AccessToken accessTocken) {
        if (TOKEN_TICKET_CACHE != null && TOKEN_TICKET_CACHE.get(key) != null) {
            TOKEN_TICKET_CACHE.remove(key);
            log.info("==========从缓存中删除" + key + "成功===============");
        }
        TOKEN_TICKET_CACHE.put(key, accessTocken);
        cacheAddTime = String.valueOf(accessTocken.getAddTime());// 更新缓存修改的时间
        log.info("==========更新缓存中" + key + "成功===============");
    }



    /**
     * 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)
     */
    private static JSONObject httpRequest(String requestUrl, String requestMethod, String outputStr) {
        JSONObject jsonObject = null;
        StringBuffer buffer = new StringBuffer();
        try {
            // 创建SSLContext对象，并使用我们指定的信任管理器初始化
            TrustManager[] tm = { new MyX509TrustManager() };
            SSLContext sslContext = SSLContext.getInstance("SSL", "SunJSSE");
            sslContext.init(null, tm, new java.security.SecureRandom());
            // 从上述SSLContext对象中得到SSLSocketFactory对象
            SSLSocketFactory ssf = sslContext.getSocketFactory();

            URL url = new URL(requestUrl);
            HttpsURLConnection httpUrlConn = (HttpsURLConnection) url.openConnection();
            httpUrlConn.setSSLSocketFactory(ssf);

            httpUrlConn.setDoOutput(true);
            httpUrlConn.setDoInput(true);
            httpUrlConn.setUseCaches(false);
            // 设置请求方式（GET/POST）
            httpUrlConn.setRequestMethod(requestMethod);
            if ("GET".equalsIgnoreCase(requestMethod))
                httpUrlConn.connect();
            // 当有数据需要提交时
            if (null != outputStr) {
                OutputStream outputStream = httpUrlConn.getOutputStream();
                // 注意编码格式，防止中文乱码
                outputStream.write(outputStr.getBytes("UTF-8"));
                outputStream.close();
            }
            // 将返回的输入流转换成字符串
            InputStream inputStream = httpUrlConn.getInputStream();
            InputStreamReader inputStreamReader = new InputStreamReader(inputStream, "utf-8");
            BufferedReader bufferedReader = new BufferedReader(inputStreamReader);
            String str = null;
            while ((str = bufferedReader.readLine()) != null) {
                buffer.append(str);
            }
            bufferedReader.close();
            inputStreamReader.close();
            // 释放资源
            inputStream.close();
            inputStream = null;
            httpUrlConn.disconnect(); 
            jsonObject = JSONObject.parseObject(buffer.toString());
            // jsonObject = JSONObject.fromObject(buffer.toString());
        } catch (ConnectException ce) {
            log.info("Weixin server connection timed out.");
        } catch (Exception e) {
            log.info("https request error:{}" + e.getMessage());
        }
        return jsonObject;
    }