从OAuth2Request提取HttpServletRequest构造函数所需的查询参数

    private static final String CLIENT_ID_PARAM = "client_id";
    private static final String REDIRECT_URI_PARAM = "redirect_uri";
    private static final String SCOPE_PARAM = "scope";
    private static final String RESPONSE_TYPE_PARAM = "response_type";

    private static OAuth2Request httpToOauthRequest(final HttpServletRequest request) {
        return new OAuth2Request(
                getQueryParameters(request),request.getParameter(CLIENT_ID_PARAM),null,false,getDelimitedSetFromParameter(request.getParameter(SCOPE_PARAM),","),request.getParameter(REDIRECT_URI_PARAM),getDelimitedSetFromParameter(request.getParameter(RESPONSE_TYPE_PARAM),null
        );
    }

    private static Map<String,String> getQueryParameters(HttpServletRequest request) {
        Map<String,String> queryParameters = new HashMap<>();
        String queryString = request.getQueryString();

        if (StringUtils.isEmpty(queryString)) {
            return queryParameters;
        }

        String[] parameters = queryString.split("&");

        for (String parameter : parameters) {
            String[] keyValuePair = parameter.split("=");
            queryParameters.put(keyValuePair[0],keyValuePair[1]);
        }
        return queryParameters;
    }

    private static Set<String> getDelimitedSetFromParameter(final String parameter,final String delimiter) {
        return Sets.newHashSet(Arrays.asList(parameter.split(delimiter)));
    }