@Test
public void givenSerializeConfig_whenJavaObject_thanJsonCorrect() {
    NameFilter formatName = new NameFilter() {
        public String process(Object object, String name, Object value) {
            return name.toLowerCase()
                .replace(" ", "_");
        }
    };
    SerializeConfig.getGlobalInstance()
        .addFilter(Person.class, formatName);
    String jsonOutput = JSON.toJSONStringWithDateFormat(listOfPersons, "yyyy-MM-dd");
    assertEquals(jsonOutput, "[{\"first_name\":\"Doe\",\"last_name\":\"John\"," + "\"date_of_birth\":\"2016-07-24\"},{\"first_name\":\"Doe\",\"last_name\":" + "\"Janette\",\"date_of_birth\":\"2016-07-24\"}]");
    // resetting custom serializer
    SerializeConfig.getGlobalInstance()
        .put(Person.class, null);
}
 

public String toJSONString(Object object, SerializeFilter filter, SerializerFeature[] features) {
    SerializeWriter out = new SerializeWriter();

    try {
        JSONSerializer serializer = new JSONSerializer(out, fastJsonConfig.serializeConfig);
        if (features != null) {
            for (SerializerFeature feature : features) {
                serializer.config(feature, true);
            }
        }

        if (filter != null) {
            if (filter instanceof PropertyPreFilter) {
                serializer.getPropertyPreFilters().add((PropertyPreFilter) filter);
            }

            if (filter instanceof NameFilter) {
                serializer.getNameFilters().add((NameFilter) filter);
            }

            if (filter instanceof ValueFilter) {
                serializer.getValueFilters().add((ValueFilter) filter);
            }

            if (filter instanceof PropertyFilter) {
                serializer.getPropertyFilters().add((PropertyFilter) filter);
            }

            if (filter instanceof BeforeFilter) {
                serializer.getBeforeFilters().add((BeforeFilter) filter);
            }

            if (filter instanceof AfterFilter) {
                serializer.getAfterFilters().add((AfterFilter) filter);
            }
        }

        serializer.write(object);

        return out.toString();
    } finally {
        out.close();
    }
}