微信 网页授权，第一次能拿到用户信息，之后都拿不到

报错：
{"errcode":40029,"errmsg":"req id: L3U1QA0347ns40, invalid code"}

授权链接
https://open.weixin.qq.com/connect/oauth2/authorize?appid=wx26da4c9ef3b45d22&redirect_uri=http%3A%2F%2Fwx.yulin520.com%2Fa2a%2Fwechat%2Foauth&response_type=code&scope=snsapi_userinfo&state=1agj#wechat_redirect

java代码
public class WeChatUserInfoController {
private Log logger = LogFactory.getLog(WeChatUserInfoController.class);

private String get_access_token_url="https://api.weixin.qq.com/sns/oauth2/access_token?"
        + "appid=APPID"
        + "&secret=SECRET"
        + "&code=CODE&grant_type=authorization_code";

private String get_userinfo="https://api.weixin.qq.com/sns/userinfo?"
        + "access_token=ACCESS_TOKEN"
        + "&openid=OPENID"
        + "&lang=zh_CN";

@RequestMapping(value = "/oauth")
public String oauth(HttpServletRequest request, HttpServletResponse response) {
    logger.info("----- /wechat/oauth: 开始 -----");
    String code = ServletRequestUtils.getStringParameter(request, "code", null);
    String state = ServletRequestUtils.getStringParameter(request, "state", null);
    get_access_token_url = get_access_token_url.replace("APPID", "*****");
    get_access_token_url = get_access_token_url.replace("SECRET", "*****");
    get_access_token_url = get_access_token_url.replace("CODE", code);

    WeChatAccessToken at = getAccessToken(get_access_token_url);

    String access_token = at.getAccess_token();
    String openid = at.getOpenid();

    logger.info("----- code: 开始 -----" + code);
    logger.info("----- access_token: 开始 -----" + access_token);
    logger.info("----- openid: 开始 -----" + openid);
    logger.info("----- openid: 开始 -----" + at.getExpires_in());
    logger.info("----- openid: 开始 -----" + at.getRefresh_token());
    logger.info("----- openid: 开始 -----" + at.getScope());
    logger.info("----- openid: 开始 -----" + at.getUnionid());

    get_userinfo = get_userinfo.replace("ACCESS_TOKEN", access_token);
    get_userinfo = get_userinfo.replace("OPENID", openid);

    WeChatUserInfo ui = getUserInfo(get_userinfo);
    request.setAttribute("userInfo", ui);
    logger.info("----- /wechat/oauth: 结束 -----");
    return "/h5/activity/demo";
}

public WeChatAccessToken getAccessToken(String url){
    WeChatAccessToken at = HttpClientUtil.simpleHttpCallGet(
            url, null, null, 20000
            , new HttpClientCallBack<WeChatAccessToken>() {
                @Override
                public WeChatAccessToken handleResult(ResultBean res)
                        throws IOException {
                    GetMethod getMethod = (GetMethod) res.getValueObject();
                    WeChatAccessToken accessToken = JSON.parseObject(getMethod.getResponseBody(), WeChatAccessToken.class);
                    return accessToken;
                }
            });
    return at;
}

public WeChatUserInfo getUserInfo(String url){
    WeChatUserInfo userInfo = HttpClientUtil.simpleHttpCallGet(
            url, null, null, 20000
            , new HttpClientCallBack<WeChatUserInfo>() {
                @Override
                public WeChatUserInfo handleResult(ResultBean res)
                        throws IOException {
                    GetMethod getMethod = (GetMethod) res.getValueObject();
                    WeChatUserInfo userInfo = JSON.parseObject(getMethod.getResponseBody(), WeChatUserInfo.class);
                    return userInfo;
                }
            });
    return userInfo;
}

 首先引导用户去授权页面：
地址："https://open.weixin.qq.com/connect/oauth2/authorize?appid=appid&redirect_uri=redirect_uri&response_type=code&scope=SCOPE&state=STATE#wechat_redirect";
用户同意授权后，页面将跳转至 redirect_uri/?code=CODE&state=STATE
[php] view plaincopy在CODE上查看代码片派生到我的代码片
//通过code换取token  
$code = $_GET['code'];  
$url = "https://api.weixin.qq.com/sns/oauth2/access_token?appid=appid&secret=SECRET&code=$code&grant_type=authorization_code";  
$json = file_get_contents($url);  
$arr = json_decode($json,true);  
$token = $arr['access_token'];  
$openid = $arr['openid'];  
//拿到token后就可以获取用户基本信息了  
$url = "https://api.weixin.qq.com/sns/userinfo?access_token=$token&openid=$openid ";  
$json = file_get_contents($url);//获取微信用户基本信息  
$arr = json_decode($json,true);  
$name = $arr['nickname'];//昵称  
$imgURL = $arr['headimgurl'];//头像地址  
$sex = $arr['sex'];//性别  
$province = $arr['province'];//用户个人资料填写的省份  
$city= $arr['city'];//普通用户个人资料填写的城市  
$country= $arr['country'];//国家，如中国为CN