第三方授权方式1

实现微信授权登录

首先按照官方文档的步骤

1 第一步：用户同意授权，获取code

2 第二步：通过code换取网页授权access_token

3 第三步：刷新access_token（如果需要）

4 第四步：拉取用户信息(需scope为 snsapi_userinfo)

@WebServlet("/wxLogin")
public class LoginServlet extends HttpServlet {
    
    protected void doGet(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException {
        String backUrl = "http://url/WeixinTest/callBack";
        String url = "https://open.weixin.qq.com/connect/oauth2/authorize?"
                + "appid="+AuthUtil.APPID
                + "&redirect_uri="+URLEncoder.encode(backUrl)
                + "&response_type=code"
                + "&scope=snsapi_userinfo"
                + "&state=STATE#wechat_redirect";
        System.out.println("================");
        response.sendRedirect(url);
    }
}

@WebServlet("/callBack")
public class CallBackServlet extends HttpServlet {
    
    protected void doGet(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException {
        String code = request.getParameter("code");
        String url = "https://api.weixin.qq.com/sns/oauth2/access_token?"
                + "appid="+AuthUtil.APPID
                + "&secret="+AuthUtil.APPSECET
                + "&code="+code
                + "&grant_type=authorization_code";
        JSONObject jsonObject = AuthUtil.doGetJson(url);
        String openid = jsonObject.getString("openid");
        String token = jsonObject.getString("access_token");
        String tourl = "https://api.weixin.qq.com/sns/userinfo?"
                + "access_token="+token
                + "&openid="+openid
                + "&lang=zh_CN";
        JSONObject userInfo = AuthUtil.doGetJson(tourl);
        System.out.println(userInfo);
    }
}

包装的util

public class AuthUtil {
    public static final String  APPID = "id";
    public static final String APPSECET = "secet";
    
    public static JSONObject doGetJson(String url) throws ClientProtocolException, IOException{
        JSONObject jsonObject = null;
        DefaultHttpClient client = new DefaultHttpClient();
        HttpGet httpGet = new HttpGet(url);
        HttpResponse response = client.execute(httpGet); 
        HttpEntity entity = response.getEntity();
        if(entity!=null){
            String result = EntityUtils.toString(entity,"UTF-8");
            jsonObject = JSONObject.fromObject(result);
        }
        httpGet.releaseConnection();
        return jsonObject;
    }
}