ParserConfig parserConfig = new ParserConfig() {

            @Override

            public ObjectDeserializer getDeserializer(Type type) {

                if (type == ActionConfig.class) {

                    return super.getDeserializer(LimitActionConfig.class);

                }

                return super.getDeserializer(type);

            }

        };

        RuleConfig ruleConfig = new RuleConfig();

        ruleConfig.setDesc("xxx");

        LimitActionConfig limitActionConfig = new LimitActionConfig();

        limitActionConfig.setResponseContent("ddd");

        ruleConfig.setActionConfig(limitActionConfig);

        String text = JSON.toJSONString(ruleConfig);

        System.out.println(text);

        RuleConfig ruleConfig2 = JSON.parseObject(text, RuleConfig.class, parserConfig);

        System.out.println(ruleConfig2);