public static void main(String[] args)throws Exception{      String jsonStr1="{\"access_token\":\"OezXcEiiBSKSxW0eoylIeIVb08lFhyeFsq6cUJJNo8XYLoJjqYARJOZUrnqhfvnyMKOSjz5SHPHGUmt6f09_762MWQ0HLnZtffDPyD2A6TgCqWlZAEsHLhIaaQVYx1lywxOWQTrr7rX13i_w1INGnw\",\"expires_in\":7200,\"openid\":\"owYTUs68SXYX83wBvm_uN4Ya****\",\"scope\":\"snsapi_base\"}";        String jsonStr2="{\"access_token\":\"OezXcEiiBSKSxW0eoylIeIVb08lFhyeFsq6cUJJNo8XYLoJjqYARJOZUrnqhfvnyMKOSjz5SHPHGUmt6f09_762MWQ0HLnZtffDPyD2A6TgCqWlZAEsHLhIaaQVYx1lywxOWQTrr7rX13i_w1INGnw\",\"expires_in\":7200,\"refresh_token\":\"OezXcEiiBSKSxW0eoylIeIVb08lFhyeFsq6cUJJNo8XYLoJjqYARJOZUrnqhfvnyuq9ojibRxolf9ElS7PSM0Kz1OTNlJ8ZKJl2BfbPi0LA-nQ9uNVUE8ujLFsdCeP79_L9FmIYcmHLXWXnl-fUsVg\",\"openid\":\"owYTUs68SXYX83wBvm_uN4Y****\",\"scope\":\"snsapi_base\"}";        JSONObject json1=JSONObject.fromObject(jsonStr1);     JSONObject json2=JSONObject.fromObject(jsonStr2);     String refresh_token_1=null;     String refresh_token_2=null;     if(json1.containsKey("refresh_token")){         refresh_token_1=json1.getString("refresh_token");     }     if(json2.containsKey("refresh_token")){         refresh_token_2=json2.getString("refresh_token");     }         System.out.println(refresh_token_1);     System.out.println(refresh_token_2); }

null OezXcEiiBSKSxW0eoylIeIVb08lFhyeFsq6cUJJNo8XYLoJjqYARJOZUrnqhfvnyuq9ojibRxolf9ElS7PSM0Kz1OTNlJ8ZKJl2BfbPi0LA-nQ9uNVUE8ujLFsdCeP79_L9FmIYcmHLXWXnl-fUsVg