WechatAccessTokenUtil.java

package com.github.ouyangbob.wechat.token;

import java.util.Map;
import java.util.concurrent.TimeUnit;

import org.slf4j.Logger;
import org.slf4j.LoggerFactory;

import com.alibaba.fastjson.JSONObject;
import com.github.ouyangbob.http.HttpUtil;
import com.github.ouyangbob.wechat.WechatConstants;
import com.google.common.cache.CacheBuilder;
import com.google.common.cache.CacheLoader;
import com.google.common.cache.LoadingCache;
import com.google.common.collect.Maps;

/**
 * wechat access_token
 * 
 * @author ouyangbotao
 *
 */
public class WechatAccessTokenUtil {

	private static final String CACHE_KEY_ACCESS_TOKEN = "access_token";
	private static final String CACHE_KEY_JSAPI_TICKET = "jsapi_ticket";

	private static final Logger logger = LoggerFactory
			.getLogger(WechatAccessTokenUtil.class);

	private final static LoadingCache<String, String> cache = CacheBuilder
			.newBuilder().expireAfterWrite(7000, TimeUnit.SECONDS)
			.build(new CacheLoader<String, String>() {
				@Override
				public String load(String key) throws Exception {
					if (CACHE_KEY_ACCESS_TOKEN.equals(key)) {
						return getAccessTokenFromWeixin();
					} else if (CACHE_KEY_JSAPI_TICKET.equals(key)) {
						return getJsapiTicketFromWeixin();
					} else {
						return null;
					}
				}
			});

	public static String getAccessToken() {
		String accessToken;
		try {
			accessToken = cache.get(CACHE_KEY_ACCESS_TOKEN);
		} catch (Exception e) {
			logger.error("getAccessToken Exception:{}", e);
			accessToken = getAccessTokenFromWeixin();
			cache.put(CACHE_KEY_ACCESS_TOKEN, accessToken);
		}
		return accessToken;
	}

	public static String getJsapiTicket() {
		String jsapiTicket;
		try {
			jsapiTicket = cache.get(CACHE_KEY_JSAPI_TICKET);
		} catch (Exception e) {
			logger.error("getJsapiTicket Exception:{}", e);
			jsapiTicket = getJsapiTicketFromWeixin();
			cache.put(CACHE_KEY_JSAPI_TICKET, jsapiTicket);
		}
		return jsapiTicket;
	}

	private static String getAccessTokenFromWeixin() {
		Map<String, String> paramMap = Maps.newHashMap();
		paramMap.put("appid", WechatConstants.APPID);
		paramMap.put("secret", WechatConstants.APPSECRET);
		paramMap.put("grant_type", "client_credential");
		String body = HttpUtil.getRequest(WechatConstants.ACCESS_TOKEN,
				paramMap);
		logger.info("get access token:{}", body);

		JSONObject json = JSONObject.parseObject(body);
		String accessToken = json.getString("access_token");
		// Integer expiresIn=json.getInteger("expires_in");
		return accessToken;
	}

	private static String getJsapiTicketFromWeixin() {
		Map<String, String> paramMap = Maps.newHashMap();
		paramMap.put("access_token", getAccessToken());
		paramMap.put("type", "jsapi");
		String body = HttpUtil.getRequest(WechatConstants.JS_API_GET_TICKET,
				paramMap);
		logger.info("get jsapi ticket:{}", body);

		JSONObject json = JSONObject.parseObject(body);
		String jsapiTicket = json.getString("ticket");
		int errcode = json.getIntValue("errcode");
		if (errcode == 42001 || errcode == 40001) {
			cache.invalidate(CACHE_KEY_ACCESS_TOKEN);
			return getJsapiTicketFromWeixin();
		}
		return jsapiTicket;
	}

}