【问题】
Demo:
LocalDateTime dt = LocalDateTime.now();
ObjectMapper mapper = new ObjectMapper();
try {
String json = mapper.writeValueAsString(dt);
System.out.println(json);
} catch (JsonProcessingException e) {
e.printStackTrace();
}
Jackson默认序列化会将LocalDateTime序列化成:
{"dayOfMonth":15,"dayOfWeek":"SUNDAY","dayOfYear":258,"hour":14,"minute":6,"month":"SEPTEMBER","monthValue":9,"nano":359000000,"second":55,"year":2019,"chronology":{"id":"ISO","calendarType":"iso8601"}}
并且该字符串反序列化成LocalDateTime会报错:
Cannot construct instance of `java.time.LocalDateTime`
Demo:
String json = "{\"dayOfMonth\":15,\"dayOfWeek\":\"SUNDAY\",\"dayOfYear\":258,\"hour\":14,\"minute\":2,\"month\":\"SEPTEMBER\",\"monthValue\":9,\"nano\":71000000,\"second\":46,\"year\":2019,\"chronology\":{\"id\":\"ISO\",\"calendarType\":\"iso8601\"}}";
ObjectMapper mapper = new ObjectMapper();
try {
LocalDateTime dt = mapper.readValue(json, LocalDateTime.class);
System.out.println(dt);
} catch (IOException e) {
e.printStackTrace();
}
就算加了:
mapper.disable(SerializationFeature.WRITE_DATES_AS_TIMESTAMPS);
mapper.registerModule(new JavaTimeModule());
也会报如下错误:
com.fasterxml.jackson.databind.exc.MismatchedInputException: Expected array or string.
Demo:
String json = "{\"dayOfMonth\":15,\"dayOfWeek\":\"SUNDAY\",\"dayOfYear\":258,\"hour\":14,\"minute\":2,\"month\":\"SEPTEMBER\",\"monthValue\":9,\"nano\":71000000,\"second\":46,\"year\":2019,\"chronology\":{\"id\":\"ISO\",\"calendarType\":\"iso8601\"}}";
ObjectMapper mapper = new ObjectMapper();
try {
mapper.disable(SerializationFeature.WRITE_DATES_AS_TIMESTAMPS);
mapper.registerModule(new JavaTimeModule());
LocalDateTime dt = mapper.readValue(json, LocalDateTime.class);
System.out.println(dt);
} catch (IOException e) {
e.printStackTrace();
}
【解决方案】
思路:
改变jackson内部序列化和反序列化LocalDateTime的方式,序列化时转换为时间戳,反序列化时将时间戳转换为LocalDateTime即可。
代码:
创建两个类,分别继承JsonSerializer和JsonDeserializer
//时间序列化时变为时间戳
public class LocalDateTimeSerializer extends JsonSerializer<LocalDateTime> {
@Override
public void serialize(LocalDateTime localDateTime, JsonGenerator jsonGenerator, SerializerProvider serializerProvider) throws IOException {
jsonGenerator.writeNumber(localDateTime.toInstant(ZoneOffset.ofHours(8)).toEpochMilli());
}
}
//时间戳反序列化时间
public class LocalDateTimeDeserializer extends JsonDeserializer<LocalDateTime> {
@Override
public LocalDateTime deserialize(JsonParser jsonParser, DeserializationContext deserializationContext) throws IOException, JsonProcessingException {
Long timestamp = jsonParser.getLongValue();
return LocalDateTime.ofEpochSecond(timestamp / 1000, 0, ZoneOffset.ofHours(8));
}
}
使用方法(序列化添加如下3行红色代码)
LocalDateTime dt = LocalDateTime.now();
ObjectMapper mapper = new ObjectMapper();
try {
JavaTimeModule timeModule = new JavaTimeModule();
timeModule.addSerializer(LocalDateTime.class, new LocalDateTimeSerializer());
mapper.registerModule(timeModule);
String json = mapper.writeValueAsString(dt);
System.out.println(json);
} catch (JsonProcessingException e) {
e.printStackTrace();
}
* 经过此方式序列化得到的结果为:"1568528927273"
使用方法(反序列化添加如下3行红色代码)
String json = "1568528927273";
ObjectMapper mapper = new ObjectMapper();
try {
JavaTimeModule timeModule = new JavaTimeModule();
timeModule.addDeserializer(LocalDateTime.class, new LocalDateTimeDeserializer());
mapper.registerModule(timeModule);
LocalDateTime dt = mapper.readValue(json, LocalDateTime.class);
System.out.println(dt);
} catch (IOException e) {
e.printStackTrace();
}
以上就是本文所有内容~~~ 欢迎交流,,分享~~~
来源:oschina
链接:https://my.oschina.net/u/4290613/blog/3396280