微信平台自动获取Token

微信公众平台的Token有时间限制，超时后需要重新获取。

import java.text.SimpleDateFormat;
import java.util.Calendar;
import java.util.Date;
import java.util.Properties;
import net.sf.json.JSONObject;
import org.apache.commons.logging.Log;
import org.apache.commons.logging.LogFactory;

/**
 * 令牌如果过期重新获取Toekn，否则返回配置文件中的Token
 * @author wpj
 */
public class WeixinTokenUtil {

    private final String ACCESS_TOKEN_URL = "https://api.weixin.qq.com/cgi-bin/token";
    private final Log logger = LogFactory.getLog(WeixinTokenUtil.class);

    /**
     * 获取令牌
     * @return AccessToken
     */
    public String getAccessToken() {
        String accessToken = "";
        SimpleDateFormat sdf = new SimpleDateFormat("yyyy-MM-dd HH:mm:ss");

        String filePath = this.getClass().getResource("/") + "";
        filePath = filePath.replace("classes/", "weixin.properties");
        filePath = filePath.replace("file:/", "");
        System.out.println("文件路径："+filePath);
        Properties pro = PropertiesUtil.getProperties(filePath);

        String accessTime = pro.getProperty("Access_Token_Time");
        if (isTokenOverTime(accessTime)) {
            String url = ACCESS_TOKEN_URL + "?grant_type=client_credential&";
            String appID = pro.getProperty("AppID");
            String secret = pro.getProperty("Secret");
            String param = "appid=" + appID + "&secret=" + secret;
            JSONObject jasonObject = JSONObject.fromObject(HttpRequestUtil.sendHttpsGet(url, param));
            accessToken = jasonObject.get("access_token").toString();
            if ("".equals(accessToken)) {
                logger.info("获取AccessToken失败:" + jasonObject.get("errmsg").toString());
            } else {
                pro.setProperty("Access_Token", accessToken);
                pro.setProperty("Access_Token_Time", sdf.format(new Date()));
                String flag = PropertiesUtil.setProperties(pro, filePath) ? "成功" : "失败";
                logger.info("更新本地AccessToken成功" + flag + ":" + accessToken);
            }
        } else {
            accessToken = pro.getProperty("Access_Token");
        }
        return accessToken;
    }

    /**
     * 验证令牌是否过期
     * @param accessTime
     * @return 
     */
    private boolean isTokenOverTime(String accessTime) {
        SimpleDateFormat sdf = new SimpleDateFormat("yyyy-MM-dd HH:mm:ss");
        Calendar cal = Calendar.getInstance();
        long time1 = 0;
        long time2 = 0;
        try {
            cal.setTime(sdf.parse(accessTime));
            time1 = cal.getTimeInMillis();
            cal.setTime(new Date());
            time2 = cal.getTimeInMillis();
        } catch (Exception e) {
            e.printStackTrace();
        }
        long between_hours = (time2 - time1) / (1000 * 60);
        logger.info("AccessToken时间差:" + between_hours);
        return between_hours > 115;
    }

    public static void main(String[] args) {
        WeixinTokenUtil wtu = new WeixinTokenUtil();
        System.out.println(wtu.getAccessToken());
    }
}