[英]Java 8 LocalDate Jackson format
对于java.util.Date当我做
@JsonFormat(shape = JsonFormat.Shape.STRING, pattern = "dd/MM/yyyy")
private Date dateOfBirth;
然后在我发送时在 JSON 请求中
{ {"dateOfBirth":"01/01/2000"} }
有用。
我应该如何为Java 8 的 LocalDate字段执行此操作?
我试着有
@JsonDeserialize(using = LocalDateDeserializer.class)
@JsonSerialize(using = LocalDateSerializer.class)
private LocalDate dateOfBirth;
它没有用。
有人可以让我知道这样做的正确方法是什么..
以下是依赖项
<dependency>
<groupId>org.jboss.resteasy</groupId>
<artifactId>jaxrs-api</artifactId>
<version>3.0.9.Final</version>
</dependency>
<dependency>
<groupId>com.fasterxml.jackson.jaxrs</groupId>
<artifactId>jackson-jaxrs-json-provider</artifactId>
<version>2.4.2</version>
</dependency>
<dependency>
<groupId>com.wordnik</groupId>
<artifactId>swagger-annotations</artifactId>
<version>1.3.10</version>
</dependency>
我从来没有能够使用注释让它简单地工作。 为了得到它的工作,我创建了一个ContextResolver
为ObjectMapper
,然后我添加了JSR310Module
(更新:现在是JavaTimeModule
代替),多一个警告沿,这是需要一套写日期的时间戳为false。 在 JSR310 模块的文档中查看更多信息。 这是我使用的示例。
依赖
<dependency>
<groupId>com.fasterxml.jackson.datatype</groupId>
<artifactId>jackson-datatype-jsr310</artifactId>
<version>2.4.0</version>
</dependency>
注意:我遇到的一个问题是jackson-annotation
版本由另一个依赖项jsr310
,使用版本 2.3.2,它取消了jsr310
所需的 2.4。 发生的事情是我为ObjectIdResolver
获得了一个 NoClassDefFound ,这是一个 2.4 类。 所以我只需要排列包含的依赖版本
上下文解析器
import com.fasterxml.jackson.databind.ObjectMapper;
import com.fasterxml.jackson.databind.SerializationFeature;
import com.fasterxml.jackson.datatype.jsr310.JSR310Module;
import javax.ws.rs.ext.ContextResolver;
import javax.ws.rs.ext.Provider;
@Provider
public class ObjectMapperContextResolver implements ContextResolver<ObjectMapper> {
private final ObjectMapper MAPPER;
public ObjectMapperContextResolver() {
MAPPER = new ObjectMapper();
// Now you should use JavaTimeModule instead
MAPPER.registerModule(new JSR310Module());
MAPPER.configure(SerializationFeature.WRITE_DATES_AS_TIMESTAMPS, false);
}
@Override
public ObjectMapper getContext(Class<?> type) {
return MAPPER;
}
}
资源类
@Path("person")
public class LocalDateResource {
@GET
@Produces(MediaType.APPLICATION_JSON)
public Response getPerson() {
Person person = new Person();
person.birthDate = LocalDate.now();
return Response.ok(person).build();
}
@POST
@Consumes(MediaType.APPLICATION_JSON)
public Response createPerson(Person person) {
return Response.ok(
DateTimeFormatter.ISO_DATE.format(person.birthDate)).build();
}
public static class Person {
public LocalDate birthDate;
}
}
测试
curl -v http://localhost:8080/api/person
结果:{"birthDate":"2015-03-01"}
curl -v -POST -H "Content-Type:application/json" -d "{\\"birthDate\\":\\"2015-03-01\\"}" http://localhost:8080/api/person
结果:2015-03-01
另请参阅此处了解 JAXB 解决方案。
JSR310Module
从 Jackson 2.7 版JSR310Module
被弃用。 相反,您应该注册模块JavaTimeModule
。 它仍然是相同的依赖关系。
@JsonSerialize 和 @JsonDeserialize 对我来说效果很好。 它们无需导入额外的 jsr310 模块:
@JsonDeserialize(using = LocalDateDeserializer.class)
@JsonSerialize(using = LocalDateSerializer.class)
private LocalDate dateOfBirth;
解串器:
public class LocalDateDeserializer extends StdDeserializer<LocalDate> {
private static final long serialVersionUID = 1L;
protected LocalDateDeserializer() {
super(LocalDate.class);
}
@Override
public LocalDate deserialize(JsonParser jp, DeserializationContext ctxt)
throws IOException, JsonProcessingException {
return LocalDate.parse(jp.readValueAs(String.class));
}
}
序列化器:
public class LocalDateSerializer extends StdSerializer<LocalDate> {
private static final long serialVersionUID = 1L;
public LocalDateSerializer(){
super(LocalDate.class);
}
@Override
public void serialize(LocalDate value, JsonGenerator gen, SerializerProvider sp) throws IOException, JsonProcessingException {
gen.writeString(value.format(DateTimeFormatter.ISO_LOCAL_DATE));
}
}
ObjectMapper mapper = new ObjectMapper();
mapper.registerModule(new JavaTimeModule());
mapper.configure(SerializationFeature.WRITE_DATES_AS_TIMESTAMPS, false);
在 Spring Boot Web 应用程序中,使用Jackson和JSR 310版本“2.8.5”
compile "com.fasterxml.jackson.core:jackson-databind:2.8.5"
runtime "com.fasterxml.jackson.datatype:jackson-datatype-jsr310:2.8.5"
@JsonFormat
有效:
import com.fasterxml.jackson.annotation.JsonFormat;
@JsonFormat(shape = JsonFormat.Shape.STRING, pattern = "yyyy-MM-dd")
private LocalDate birthDate;
最简单的解决方案(也支持反序列化和序列化)是
import com.fasterxml.jackson.annotation.JsonFormat;
import com.fasterxml.jackson.databind.annotation.JsonDeserialize;
import com.fasterxml.jackson.databind.annotation.JsonSerialize;
import com.fasterxml.jackson.datatype.jsr310.deser.LocalDateDeserializer;
import com.fasterxml.jackson.datatype.jsr310.ser.LocalDateSerializer;
@JsonFormat(shape = JsonFormat.Shape.STRING, pattern = "dd/MM/yyyy")
@JsonDeserialize(using = LocalDateDeserializer.class)
@JsonSerialize(using = LocalDateSerializer.class)
private LocalDate dateOfBirth;
在您的项目中使用以下依赖项时。
马文
<dependency>
<groupId>com.fasterxml.jackson.core</groupId>
<artifactId>jackson-databind</artifactId>
<version>2.9.7</version>
</dependency>
<dependency>
<groupId>com.fasterxml.jackson.datatype</groupId>
<artifactId>jackson-datatype-jsr310</artifactId>
<version>2.9.7</version>
</dependency>
摇篮
compile "com.fasterxml.jackson.core:jackson-databind:2.9.7"
compile "com.fasterxml.jackson.datatype:jackson-datatype-jsr310:2.9.7"
不需要额外的 ContextResolver、Serializer 或 Deserializer 实现。
@JsonFormat(pattern = "yyyy-MM-dd HH:mm:ss")
@JsonSerialize(using = LocalDateTimeSerializer.class)
@JsonDeserialize(using = LocalDateTimeDeserializer.class)
private LocalDateTime createdDate;
由于LocalDateSerializer
将其转换为“[year,month,day]”(一个 json 数组)而不是“year-month-day”(一个 json 字符串),并且因为我不想需要任何特殊的ObjectMapper
设置(如果禁用SerializationFeature.WRITE_DATES_AS_TIMESTAMPS
,则可以使LocalDateSerializer
生成字符串,但这需要对ObjectMapper
额外设置),我使用以下内容:
进口:
import com.fasterxml.jackson.databind.ser.std.ToStringSerializer;
import com.fasterxml.jackson.datatype.jsr310.deser.LocalDateDeserializer;
代码:
// generates "yyyy-MM-dd" output
@JsonSerialize(using = ToStringSerializer.class)
// handles "yyyy-MM-dd" input just fine (note: "yyyy-M-d" format will not work)
@JsonDeserialize(using = LocalDateDeserializer.class)
private LocalDate localDate;
现在我可以使用new ObjectMapper()
来读取和写入我的对象而无需任何特殊设置。
以下注释对我来说效果很好。
不需要额外的依赖。
@JsonProperty("created_at")
@JsonFormat(pattern = "yyyy-MM-dd'T'HH:mm:ss.SSSXXX")
@JsonDeserialize(using = LocalDateTimeDeserializer.class)
@JsonSerialize(using = LocalDateTimeSerializer.class)
private LocalDateTime createdAt;
@JsonFormat(pattern = "yyyy-MM-dd")
private LocalDate localDate;
@JsonFormat(pattern = "yyyy-MM-dd HH:mm:ss")
private LocalDateTime localDateTime;
Spring boot >= 2.2+ 不需要依赖项
只是克里斯托弗回答的更新。
自2.6.0版本
<dependency>
<groupId>com.fasterxml.jackson.datatype</groupId>
<artifactId>jackson-datatype-jsr310</artifactId>
<version>2.9.0</version>
</dependency>
使用JavaTimeModule而不是JSR310Module (已弃用)。
@Provider
public class ObjectMapperContextResolver implements ContextResolver<ObjectMapper> {
private final ObjectMapper MAPPER;
public ObjectMapperContextResolver() {
MAPPER = new ObjectMapper();
MAPPER.registerModule(new JavaTimeModule());
MAPPER.configure(SerializationFeature.WRITE_DATES_AS_TIMESTAMPS, false);
}
@Override
public ObjectMapper getContext(Class<?> type) {
return MAPPER;
}
}
根据文档,新的 JavaTimeModule 使用相同的标准设置默认为不使用时区 ID 的序列化,而是仅使用符合 ISO-8601 的时区偏移量。
可以使用SerializationFeature.WRITE_DATES_WITH_ZONE_ID更改行为
https://stackoverflow.com/a/53251526/1282532是序列化/反序列化属性的最简单方法。 我对这种方法有两个担忧——在某种程度上违反了 DRY 原则以及 pojo 和 mapper 之间的高耦合。
public class Trade {
@JsonFormat(pattern = "yyyyMMdd")
@JsonDeserialize(using = LocalDateDeserializer.class)
@JsonSerialize(using = LocalDateSerializer.class)
private LocalDate tradeDate;
@JsonFormat(pattern = "yyyyMMdd")
@JsonDeserialize(using = LocalDateDeserializer.class)
@JsonSerialize(using = LocalDateSerializer.class)
private LocalDate maturityDate;
@JsonFormat(pattern = "yyyyMMdd")
@JsonDeserialize(using = LocalDateDeserializer.class)
@JsonSerialize(using = LocalDateSerializer.class)
private LocalDate entryDate;
}
如果您的 POJO 具有多个 LocalDate 字段,最好配置映射器而不是 POJO。 如果您使用的是 ISO-8601 值(“2019-01-31”),它可以像https://stackoverflow.com/a/35062824/1282532一样简单
如果您需要处理自定义格式,代码将如下所示:
ObjectMapper mapper = new ObjectMapper();
JavaTimeModule javaTimeModule = new JavaTimeModule();
javaTimeModule.addDeserializer(LocalDate.class, new LocalDateDeserializer(DateTimeFormatter.ofPattern("yyyyMMdd")));
javaTimeModule.addSerializer(LocalDate.class, new LocalDateSerializer(DateTimeFormatter.ofPattern("yyyyMMdd")));
mapper.registerModule(javaTimeModule);
逻辑只写一次,可以复用多个POJO
从 2020 年和 Jackson 2.10.1 开始,不需要任何特殊代码,只需告诉 Jackson 你想要什么:
ObjectMapper objectMapper = new ObjectMapper();
// Register module that knows how to serialize java.time objects
// Provided by jackson-datatype-jsr310
objectMapper.registerModule(new JavaTimeModule());
// Ask Jackson to serialize dates as String (ISO-8601 by default)
objectMapper.disable(SerializationFeature.WRITE_DATES_AS_TIMESTAMPS);
这已经在这个答案中提到了,我正在添加一个单元测试来验证功能:
import com.fasterxml.jackson.annotation.JsonFormat;
import com.fasterxml.jackson.core.JsonProcessingException;
import com.fasterxml.jackson.databind.ObjectMapper;
import com.fasterxml.jackson.databind.SerializationFeature;
import com.fasterxml.jackson.datatype.jsr310.JavaTimeModule;
import lombok.Data;
import org.junit.jupiter.api.Test;
import java.time.LocalDate;
import static org.junit.jupiter.api.Assertions.assertEquals;
public class LocalDateSerializationTest {
@Data
static class TestBean {
// Accept default ISO-8601 format
LocalDate birthDate;
// Use custom format
@JsonFormat(shape = JsonFormat.Shape.STRING, pattern = "dd/MM/yyyy")
LocalDate birthDateWithCustomFormat;
}
@Test
void serializeDeserializeTest() throws JsonProcessingException {
ObjectMapper objectMapper = new ObjectMapper();
// Register module that knows how to serialize java.time objects
objectMapper.registerModule(new JavaTimeModule());
// Ask Jackson to serialize dates as String (ISO-8601 by default)
objectMapper.disable(SerializationFeature.WRITE_DATES_AS_TIMESTAMPS);
// The JSON string after serialization
String json = "{\"birthDate\":\"2000-01-02\",\"birthDateWithCustomFormat\":\"03/02/2001\"}";
// The object after deserialization
TestBean object = new TestBean();
object.setBirthDate(LocalDate.of(2000, 1, 2));
object.setBirthDateWithCustomFormat(LocalDate.of(2001, 2, 3));
// Assert serialization
assertEquals(json, objectMapper.writeValueAsString(object));
// Assert deserialization
assertEquals(object, objectMapper.readValue(json, TestBean.class));
}
}
TestBean 使用 Lombok 为 bean 生成样板。
在配置类中定义LocalDateSerializer和LocalDateDeserializer类,并通过JavaTimeModule将它们注册到ObjectMapper ,如下所示:
@Configuration
public class AppConfig
{
@Bean
public ObjectMapper objectMapper()
{
ObjectMapper mapper = new ObjectMapper();
mapper.setSerializationInclusion(Include.NON_EMPTY);
//other mapper configs
// Customize de-serialization
JavaTimeModule javaTimeModule = new JavaTimeModule();
javaTimeModule.addSerializer(LocalDate.class, new LocalDateSerializer());
javaTimeModule.addDeserializer(LocalDate.class, new LocalDateDeserializer());
mapper.registerModule(javaTimeModule);
return mapper;
}
public class LocalDateSerializer extends JsonSerializer<LocalDate> {
@Override
public void serialize(LocalDate value, JsonGenerator gen, SerializerProvider serializers) throws IOException {
gen.writeString(value.format(Constant.DATE_TIME_FORMATTER));
}
}
public class LocalDateDeserializer extends JsonDeserializer<LocalDate> {
@Override
public LocalDate deserialize(JsonParser p, DeserializationContext ctxt) throws IOException {
return LocalDate.parse(p.getValueAsString(), Constant.DATE_TIME_FORMATTER);
}
}
}
对于 Spring 来说更容易一些:
///...
@Configuration
public class ApplicationCtxBeans {
//....
@Bean
public ObjectMapper objectMapper() {
ObjectMapper MAPPER = new ObjectMapper();
MAPPER.registerModule(new JavaTimeModule()); // to handle LocalDateTime etc
return MAPPER;
}
//...
}
用法:
@Service
public class SomeService {
//...
@Autowired
ObjectMapper jsonMapper;
//...
JsonNode node = jsonMapper.readTree(
jsonMapper.writeValueAsString(instance_Of_Class_With_LocalDate_Fields)
);
//...
}
如果您的请求包含这样的对象:
{
"year": 1900,
"month": 1,
"day": 20
}
然后你可以使用:
data class DateObject(
val day: Int,
val month: Int,
val year: Int
)
class LocalDateConverter : StdConverter<DateObject, LocalDate>() {
override fun convert(value: DateObject): LocalDate {
return value.run { LocalDate.of(year, month, day) }
}
}
场上:
@JsonDeserialize(converter = LocalDateConverter::class)
val dateOfBirth: LocalDate
代码在 Kotlin 中,但这当然也适用于 Java。
使用 spring boot 2.3.9.RELEASE,我刚刚在具有 LocalDate 字段的 POJO 类中注册了没有显式注释的 java 时间模块,它工作正常。
var objectMapper = new ObjectMapper();
objectMapper.registerModule(new JavaTimeModule());
Pojo 中的注释而不使用额外的依赖项
@DateTimeFormat (pattern = "yyyy/MM/dd", iso = DateTimeFormat.ISO.DATE)
private LocalDate enddate;
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