我正在尝试将Jackson的String
反序列化为LocalDateTime
,但这是行不通的。
我有一个带有LocalDateTime字段的数据类:
@Data
public class Registration {
@JsonFormat(shape = JsonFormat.Shape.STRING, pattern = "yyyy-MM-dd hh:mm:ss")
private LocalDateTime timestamp;
}
我添加了特殊的Jackson数据类型模块:
compile("com.fasterxml.jackson.datatype:jackson-datatype-jsr310")
序列化可以很好地配合:
new ObjectMapper().registerModule(new JavaTimeModule()).writeValueAsString(registration);
结果字符串:
{"timestamp":"2018-09-03 10:09:35"}
但是反序列化不适用于:
new ObjectMapper().registerModule(new JavaTimeModule()).readValue(json.traverse(), Registration.class)
作为错误我得到:
Cannot deserialize value of type `java.time.LocalDateTime` from String "2018-09-03 10:09:35":
Failed to deserialize java.time.LocalDateTime:
(java.time.format.DateTimeParseException) Text '2018-09-03 10:09:35' could not be parsed:
Unable to obtain LocalDateTime from TemporalAccessor:
{MinuteOfHour=9, NanoOfSecond=0, SecondOfMinute=35, MicroOfSecond=0, MilliOfSecond=0, HourOfAmPm=10},
ISO resolved to 2018-09-03 of type java.time.format.Parsed
我想念什么?我很困惑序列化有效,但是反序列化却无效。
MWE:(小型Gradle Java项目)
Main.java:
import java.io.IOException;
import java.time.LocalDateTime;
import com.fasterxml.jackson.annotation.JsonFormat;
import com.fasterxml.jackson.core.TreeNode;
import com.fasterxml.jackson.databind.ObjectMapper;
import com.fasterxml.jackson.datatype.jsr310.JavaTimeModule;
public class Main {
public static void main(String[] args) throws IOException {
Registration registration = new Registration();
registration.setTimestamp(LocalDateTime.now());
ObjectMapper objectMapper = new ObjectMapper().registerModule(new JavaTimeModule());
String s = objectMapper.writeValueAsString(registration);
TreeNode treeNode = objectMapper.readTree(s);
//Fails here:
Registration registration1 = objectMapper.readValue(treeNode.traverse(), Registration.class);
System.out.println(registration1);
}
}
class Registration {
@JsonFormat(shape = JsonFormat.Shape.STRING, pattern = "yyyy-MM-dd hh:mm:ss")
private LocalDateTime timestamp;
public Registration() {
}
public LocalDateTime getTimestamp() {
return this.timestamp;
}
public void setTimestamp(LocalDateTime localDateTime) {
this.timestamp = localDateTime;
}
}
build.gradle:
plugins {
id 'java'
}
group 'dateMWE'
version '1.0-SNAPSHOT'
sourceCompatibility = 10
repositories {
mavenCentral()
}
dependencies {
compile("com.fasterxml.jackson.core:jackson-annotations:2.9.6")
compile("com.fasterxml.jackson.datatype:jackson-datatype-jsr310:2.9.6")
}
答案 0 :(得分:6)
问题与JSON反序列化无关,而与时间格式字符串有关:
pattern = "yyyy-MM-dd hh:mm:ss"
请注意,小时设置为hh
:这是一个12小时格式程序,需要“ AM”或“ PM”值。
如果图案更改为
pattern = "yyyy-MM-dd HH:mm:ss"
问题应该解决。
答案 1 :(得分:1)
由于您正在使用new创建对象,因此Spring不会管理您的ObjectMapper。在配置文件中将ObjectMapper
配置为Bean。您需要向DateTimeFormat
注册LocalDateTimeDeserializer
。然后在JavaTimeModule中设置反序列化器。
@Bean
Public ObjectMapper objectMapper() {
JavaTimeModule module = new JavaTimeModule();
LocalDateTimeDeserializer localDateTimeDeserializer = new
LocalDateTimeDeserializer(DateTimeFormatter.ofPattern("yyyy-MM-dd HH:mm:ss"));
module.addDeserializer(LocalDateTime.class, localDateTimeDeserializer);
ObjectMapper objectMapperObj = Jackson2ObjectMapperBuilder.json()
.modules(module)
.featuresToDisable(SerializationFeature.WRITE_DATES_AS_TIMESTAMPS)
.build();
return objectMapperObj ;
在您的Spring配置中设置以上配置。