How should I put json in GET request?

I want to implement GET request by spring for android. I do not know how should put json in the url for that. The url is:

context.getString(R.string.url) + "services/promotions?limit=10&where={expiredAt:{$gte: \""+getCurrentDate()+"\"}}"; that I want to set but the the request fails and got this error on logcat:

Syntax error in regexp pattern near index \Qhttp://baas.papata.ir/services/promotions?limit=1&where=\E({$gte: "2014-05-05T14:48:20Z")\Q}\^

What is the problem?

Update: My class that I use that url is:

public class GetPromotion extends AsyncTask<Void, Void, Promotion[]> {

private String SERVICE_ID = "5345345";
private String API_VERSION = "0.1.0";
private String url;
private String clientId;
private Context context;
private OnGetPromotion onGetPromotion;

public GetPromotion(Context context, String clientId){
    url = context.getString(R.string.url) + "services/promotions?limit=10&where={expiredAt:{$gte: \""+getCurrentDate()+"\"}}";
    this.clientId = clientId;
    this.context = context;
}
@Override
protected Promotion[] doInBackground(Void... voids) {
    try {
        HttpHeaders requestHeaders = new HttpHeaders();
        requestHeaders.add("firstParam", API_VERSION);
        requestHeaders.add("secondParam", SERVICE_ID);
        requestHeaders.add("Cache-Control", "no-cache");

        requestHeaders.setAccept(Collections.singletonList(new MediaType("application", "json")));
        HttpEntity<?> requestEntity = new HttpEntity<Object>(requestHeaders);
        RestTemplate restTemplate = new RestTemplate(true);
        restTemplate.setRequestFactory(new HttpComponentsClientHttpRequestFactory());
        restTemplate.getMessageConverters().add(
                new MappingJackson2HttpMessageConverter());
        restTemplate.getMessageConverters().add(
                new StringHttpMessageConverter());
        ResponseEntity<Promotion[]> response = restTemplate
                .exchange(url, HttpMethod.GET, requestEntity,
                        Promotion[].class);
        return response.getBody();

    } catch (Exception e)
        return null;
    }

}

@Override
protected void onPostExecute(Promotion[] result) {
    super.onPostExecute(result);
    onGetPromotion.getOnGetPromotion(result);
}

private String getCurrentDate() {
    TimeZone tz = TimeZone.getTimeZone("UTC");
    DateFormat df = new SimpleDateFormat("yyyy-MM-dd'T'HH:mm:ss'Z'");
    df.setTimeZone(tz);
    return df.format(new Date());
} 
}

you need to encode json to URL and then concatenate with service URL. Also you would need to quote key with ".

String json_to_url=URLEncoder.encode("{\"expiredAt\":{\"$gte\":\"" + getCurrentDate() + "\"}}", "utf-8");

String serviceURL=context.getString(R.string.url) + "services/promotions?limit=10&where="+ json_to_url;

Better approach would be using POST to submit data instead GET