String text = JSON.toJSONString(v, mapping,
SerializerFeature.WriteMapNullValue);
Assert.assertEquals("{\"value\":123}", text);
ParserConfig config = new ParserConfig();
config.setAsmEnable(false);
V0 v1 = JSON.parseObject(text, V0.class, config,
JSON.DEFAULT_PARSER_FEATURE);
Assert.assertEquals(v1.getValue(), v.getValue());