oauth2的简单介绍以及应用

推荐阅读这篇文章：https://www.cnblogs.com/flashsun/p/7424071.html

 http://www.ruanyifeng.com/blog/2014/05/oauth_2_0.html

下面是我实战中用到的案例：

    @GetMapping("/login")
    public String login(HttpServletRequest request, HttpServletResponse response) {
        
        HttpSession session = request.getSession();
        //判断session中是否存在UserInfo
        Object userInfo = session.getAttribute("UserInfo");
        if (userInfo == null) {
            //判断是否带有code参数
            String code = request.getParameter("code");
            if (code == null) {
                try {
                    //重定向到授权服务器，获取到code参数
                    response.sendRedirect(AuthUtils.getAdminBackUrl(request));
                } catch (IOException e) {
                    e.printStackTrace();
                }
                return null;
            } else {
                try {
                    //code不为空，带着code去获取token值
                    URI uri = URI.create(AuthUtils.getAccessTokenUrl(code));
                    String template = restTemplate.getForObject(uri, String.class);
                    //Auth是自定义封装的实体类，封装的是从授权服务器返回的数据，有token和openid等参数
                    Auth auth = JSONObject.parseObject(template, Auth.class);
                    if (template == null) {
                        request.getSession().invalidate();
                        response.sendRedirect(AuthUtils.getAdminBackUrl(request));
                    }
                    assert template != null;
                    String access_token = auth.getData().get("access_token");
                    String open_id = auth.getData().get("openid");
                    //把返回的token和openid存入session中
                    session.setAttribute("access_token", access_token);
                    session.setAttribute("open_id", open_id);
                    logger.info("access_token:" + access_token);
                    //根据openid和token值去授权服务器获得用户信息，具体返回的什么信息看授权服务器
                    URI userUri = URI.create(AuthUtils.getUserInfoUrl(open_id, access_token));
                    String forObject = restTemplate.getForObject(userUri, String.class);
                    UserInfo info = JSONObject.parseObject(forObject, UserInfo.class);
                    if (info == null) {
                        request.getSession().invalidate();
                        response.sendRedirect(AuthUtils.getAdminBackUrl(request));
                    }
                    //把用户信息存入session中
                    session.setAttribute("UserInfo", info);
                } catch (Exception e) {
                    request.getSession().invalidate();
                    try {
                        response.sendRedirect(AuthUtils.getAdminBackUrl(request));
                    } catch (IOException e1) {
                        e1.printStackTrace();
                    }
                    return null;
                }
            }
        }
        return "login";
    }

@Component
public class AuthUtils {

    public static final String APP_USER_AUTH_WEB_URL = "http://demo.zhunedu.com/ca/oAuth/connect/webauth";
    public static final String APP_USER_AUTH_API_URL = "http://demo.zhunedu.com/ca/oAuth/api/";


    public static final String APP_SSL_APPID = "d36b2d9dbabb4fd09931b302a84b97a6"; //此处请填写您的应用ＩＤ
    public static final String APP_SSL_APPSECRET = "fxsjbz123456"; //此处请填写您的应用密钥

    /***
     * 获取code，拼接请求路径
     * @return
     */
    public static String getAdminBackUrl(HttpServletRequest request){
        HttpSession session = request.getSession();
        StringBuffer param = new StringBuffer(APP_USER_AUTH_WEB_URL);
        StringBuffer redirect_uri = request.getRequestURL();
        try {
            param.append("?redirect_uri=").append(java.net.URLEncoder.encode(redirect_uri.toString(),"UTF-8"));
        } catch (UnsupportedEncodingException e) {
            e.printStackTrace();
        }
        param.append("&state=").append(session.getId());
        param.append("&appid=").append(APP_SSL_APPID);
        param.append("&scope=").append("web_login");
        return param.toString();
    }

    /**
     * 获取toekn，拼接请求路径
     * @param code
     * @return
     */
    public static String getAccessTokenUrl(String code){
        StringBuffer tokenParam = new StringBuffer(APP_USER_AUTH_API_URL+"accessToken");
        tokenParam.append("?appid=").append(APP_SSL_APPID);
        tokenParam.append("&secret=").append(APP_SSL_APPSECRET);
        tokenParam.append("&grant_type=").append("authorization_code");
        tokenParam.append("&code=").append(code);
        return tokenParam.toString();
    }

    /**
     * 单点登录当前登录用户信息url
     */
    public static String getUserInfoUrl(String openid,String accessToken){
        StringBuffer param = new StringBuffer("http://demo.zhunedu.com/ca/oAuth/api/userInfo");
        param.append("?access_token=").append(accessToken);
        param.append("&openid=").append(openid);
        return param.toString();
    }
}