使用Jackson将Java8 LocalDateTime序列化为UTC时间戳
使用Jackson将Java8 LocalDateTime序列化为UTC时间戳
提问于 2019-02-01 12:38:17
我刚刚将我的许多约会时间转换为LocalDateTime，每个新的(Ish) java 8时间包。到目前为止，我一直喜欢这个开关，直到我开始尝试序列化和反序列化为止。
我如何配置Jackson来支持它们？：
LocalDateTime -序列化-> UTC时间戳-反序列化-> LocalDateTime？
这里有很多关于转换为格式化字符串的材料，但我似乎找不到utc时间戳的现成解决方案。
回答 4
Stack Overflow用户
回答已采纳
发布于 2019-02-01 13:01:59
您可以为LocalDateTime自定义序列化程序和反序列化器，用于exmaple：
CustomLocalDateTimeSerializer
import com.fasterxml.jackson.core.JsonGenerator;
import com.fasterxml.jackson.databind.SerializerProvider;
import com.fasterxml.jackson.databind.ser.std.StdSerializer;
import java.io.IOException;
import java.time.LocalDateTime;
import java.time.ZoneId;
public class CustomLocalDateTimeSerializer extends StdSerializer<LocalDateTime> {
protected CustomLocalDateTimeSerializer(Class<LocalDateTime> t) {
super(t);
}
protected CustomLocalDateTimeSerializer() {
this(null);
}
@Override
public void serialize(LocalDateTime value, JsonGenerator gen, SerializerProvider sp)
throws IOException {
Long epoch = value.atZone(ZoneId.systemDefault()).toInstant().getEpochSecond();
gen.writeString(epoch.toString());
}
}CustomLocalDateTimeDesSerializer：
import com.fasterxml.jackson.core.JsonParser;
import com.fasterxml.jackson.databind.DeserializationContext;
import com.fasterxml.jackson.databind.deser.std.StdDeserializer;
import java.io.IOException;
import java.time.Instant;
import java.time.LocalDateTime;
import java.time.ZoneId;
class CustomLocalDateTimeDesSerializer extends StdDeserializer<LocalDateTime> {
protected CustomLocalDateTimeDesSerializer() {
this(null);
}
protected CustomLocalDateTimeDesSerializer(Class<LocalDateTime> t) {
super(t);
}
@Override
public LocalDateTime deserialize(JsonParser jsonparser, DeserializationContext context)
throws IOException {
Long timestamp = Long.parseLong(jsonparser.getText());
return LocalDateTime.ofInstant(Instant.ofEpochSecond(timestamp), ZoneId.systemDefault());
}
}并使用它们：
import com.fasterxml.jackson.databind.ObjectMapper;
import com.fasterxml.jackson.databind.annotation.JsonDeserialize;
import com.fasterxml.jackson.databind.annotation.JsonSerialize;
import com.fasterxml.jackson.datatype.jsr310.JavaTimeModule;
import java.time.LocalDateTime;
public class RestObject {
private LocalDateTime timestamp = LocalDateTime.now();
@JsonSerialize(using = CustomLocalDateTimeSerializer.class)
@JsonDeserialize(using = CustomLocalDateTimeDesSerializer.class)
public LocalDateTime getTimestamp() {
return timestamp;
}
public static void main(String[] args) throws Exception {
ObjectMapper objectMapper = new ObjectMapper();
// {"timestamp":"1549026058"}
System.out.println(objectMapper.writeValueAsString(new RestObject()));
}
}Stack Overflow用户
发布于 2020-04-25 13:41:25
下面的解决方案解决了将LocalDateTime序列化/反序列化为时间戳的任务，至少与spring v1.5相关，并且还包括了@xingbin的answer中没有考虑到的下一个要点。
- 如果有必要具有与
java.util.Date相同的行为，则必须使用toInstant().toEpochMilli()而不是toInstant().getEpochSecond() - 检查要反序列化的值
null - 和可选点:为Jackson
ObjectMapper指定这个序列化/反序列化配置
时间戳序列化器类：
public class LocalDateTimeSerializer extends StdSerializer<LocalDateTime> {
private static final ZoneId DEFAULT_ZONE_ID = ZoneId.of("UTC");
public LocalDateTimeSerializer() {
super(LocalDateTime.class);
}
@Override
public void serialize(final LocalDateTime value,
final JsonGenerator generator,
final SerializerProvider provider) throws IOException {
if (value != null) {
final long mills = value.atZone(DEFAULT_ZONE_ID).toInstant().toEpochMilli();
generator.writeNumber(mills);
} else {
generator.writeNull();
}
}
}时间戳反序列化器类：
public class LocalDateTimeDeserializer extends StdDeserializer<LocalDateTime> {
private static final ZoneId DEFAULT_ZONE_ID = ZoneId.of("UTC");
public LocalDateTimeDeserializer() {
super(LocalDateTime.class);
}
@Override
public LocalDateTime deserialize(final JsonParser parser,
final DeserializationContext context) throws IOException {
final long value = parser.getValueAsLong();
return LocalDateTime.ofInstant(Instant.ofEpochMilli(value), DEFAULT_ZONE_ID);
}
}对象映射器配置：
@Configuration
public class ObjectMapperConfiguration {
@Bean
public ObjectMapper objectMapper() {
final ObjectMapper objectMapper = new ObjectMapper();
final SimpleModule module = new SimpleModule();
module.addSerializer(LocalDateTime.class, new LocalDateTimeSerializer());
module.addDeserializer(LocalDateTime.class, new LocalDateTimeDeserializer());
objectMapper.registerModule(module);
return objectMapper;
}
}Stack Overflow用户
发布于 2019-02-01 14:13:50
而不是手动重写所有内容，您可以利用JavaTimeModule
ObjectMapper om = new ObjectMapper();
om.registerModule(new JavaTimeModule());
om.configure(SerializationFeature.WRITE_DATES_AS_TIMESTAMPS, true);页面原文内容由Stack Overflow提供。腾讯云小微IT领域专用引擎提供翻译支持
原文链接：
https://stackoverflow.com/questions/54479704
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