微信第三方登录App或者网站

要能够实现微信授权登录，必须有认证的微信开放平台帐号、或是微信公众号的测试帐号。

微信认证

在微信开放平台 https://open.weixin.qq.com上认证，并在资源中心创建应用。

测试帐号申请

配置url和token
url是配置你的回调地址，要在公网能够访问的，我们可以理由ngrok将自己的内网ip映射成外网可以访问的地址。
在cmd运行以下命令，就会产生你的外网地址。


把你的生成的地址放在这里，不需要加http协议，添加这个是因为在回调的时候能够成功

*token 验证实现代码

public class ServerPortal extends HttpServlet{    private static final long serialVersionUID = 1L;    private static final String token = "pengjiawen";    /**     * @see HttpServlet#HttpServlet()     */    public ServerPortal() {        super();    }    /**     * @see HttpServlet#doGet(HttpServletRequest request, HttpServletResponse response)     */    protected void doGet(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException {        String signature = request.getParameter("signature");        String timestamp = request.getParameter("timestamp");        String nonce = request.getParameter("nonce");        String echostr = request.getParameter("echostr");        System.out.println("signature:" + signature);        System.out.println("timestamp:" + timestamp);        System.out.println("nonce:" + nonce);        System.out.println("echostr:" + echostr);        PrintWriter pw = response.getWriter();        pw.append(echostr);        pw.flush();    }    /**     * @see HttpServlet#doPost(HttpServletRequest request, HttpServletResponse response)     */    protected void doPost(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException {        doGet(request, response);    }

请求工具类（APPID 和APPSECRET在帐号中可以找到 ）**

public class AuthUtil {    public static final String APPID = "wxed9a1c3c9c40ca23";    public static final String APPSECRET = "ccfd920e4b551669bb8969343cc3b1c2";    /**     * send http request and convert resposne into json object     * @param url     * @return     * @throws IOException     */    public static JSONObject doGetJson(String url) throws 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");            System.out.println(result);            jsonObject = JSONObject.fromObject(result);        }        return jsonObject;    }}

授权登录实现代码

 protected void doGet(HttpServletRequest req, HttpServletResponse resp) throws ServletException, IOException {        System.out.printf("in /WxAuth/wxLogin");//        String backUrl = "http://atwjsw.s1.natapp.cc/WxAuth/callBack";        String backUrl = "http://ec76c7d4.ngrok.io/weChat/callBackServlet";        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";//        重定向用户请求到微信授权URL        resp.sendRedirect(url);

回调代码

 @Override    protected void doGet(HttpServletRequest req, HttpServletResponse resp) throws ServletException, IOException {        //1. 获取微信回调请求中的code        System.out.printf("in WxAuth/callBack");        String code = req.getParameter("code");        String url = "https://api.weixin.qq.com/sns/oauth2/access_token?"                    + "appid=" + AuthUtil.APPID                    + "&secret=" + AuthUtil.APPSECRET                    + "&code=" + code                    + "&grant_type=authorization_code";        //2. 向微信发出请求，带上APPSCECRET和code，获取openid和access_toekn        JSONObject jsonObject = AuthUtil.doGetJson(url);        String openid = jsonObject.getString("openid");        String token = jsonObject.getString("access_token");        //4. 获取用户信息        String infoUrl = "https://api.weixin.qq.com/sns/userinfo?"                        + "access_token=" + token                        + "&openid=" + openid                        + "&lang=zh_CN";        JSONObject userInfo = AuthUtil.doGetJson(infoUrl);        System.out.println(userInfo);        //1. 使用微信用户信息直接登录，无需注册和绑定        req.setAttribute("info", userInfo);       req.getRequestDispatcher("/index1.jsp").forward(req, resp);

在过程中遇到很多问题，特别是回调地址总错误，还有内网映射为外网。