Java 8 LocalDate Jackson格式

Question

对于java.util.Date,当我这样做

@JsonFormat(shape = JsonFormat.Shape.STRING, pattern = "dd/MM/yyyy")  
  private Date dateOfBirth;

然后在我发送的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？

我试过了

@JsonDeserialize(using = LocalDateDeserializer.class)  
@JsonSerialize(using = LocalDateSerializer.class)  
private LocalDate dateOfBirth;  

它没用.

有人可以让我知道这是正确的方法吗？

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>

Answer 1

我从来没有能够使用注释使这个工作变得简单.为了让它工作,我创建了一个ContextResolverfor ObjectMapper,然后我添加了JSR310Module一个警告,这需要将write-date-as-timestamp设置为false.有关JSR310模块的文档,请参阅更多信息.这是我用过的一个例子.

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由另一个依赖项引入的版本,使用版本2.3.2,它取消了所需的2.4 jsr310.发生了什么事我得到了一个N​​oClassDefFound ObjectIdResolver,这是一个2.4级的.所以我只需要排列包含的依赖版本}

ContextResolver

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

有关JAXB解决方案,另请参见此处.

UPDATE

JSR310Module自Jackson版本2.7起,该版本已被弃用.相反,您应该注册该模块JavaTimeModule.它仍然是相同的依赖.

Answer 2

@JsonSerialize和@JsonDeserialize对我来说很好.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));
    }

}

串行:

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));
    }
}

Answer 3

ObjectMapper mapper = new ObjectMapper();
mapper.registerModule(new JavaTimeModule());
mapper.configure(SerializationFeature.WRITE_DATES_AS_TIMESTAMPS, false);

对我来说很好.

Answer 4

在春季启动网络应用程序,"杰克逊"和"jsr310"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;

Answer 5

最简单的解决方案(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;

在项目中使用以下依赖项时.

Maven的

<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"

不需要额外实现ContextResolver,Serializer或Deserializer.

Answer 6

@JsonFormat(pattern = "yyyy-MM-dd HH:mm:ss")
@JsonSerialize(using = LocalDateTimeSerializer.class)
@JsonDeserialize(using = LocalDateTimeDeserializer.class)
private LocalDateTime createdDate;

Answer 7

由于LocalDateSerializer默认情况下将其变为"[年,月,日]"(json数组)而不是"年 - 月 - 日"(json字符串),因为我不想要任何特殊ObjectMapper设置(你可以使LocalDateSerializer生成的字符串,如果你禁用SerializationFeature.WRITE_DATES_AS_TIMESTAMPS,但需要额外的安装到你的ObjectMapper),我用的是以下几点:

进口:

import com.fasterxml.jackson.databind.ser.std.ToStringSerializer;
import com.fasterxml.jackson.datatype.jsr310.deser.LocalDateDeserializer;

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;

而现在我可以使用它new ObjectMapper()来读取和写入我的对象,而无需任何特殊设置.

Answer 8

迄今为止最简单和最短的：

@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

Answer 9

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;

Answer 10

只是克里斯托弗回答的更新。

从2.6.0版开始

<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（不建议使用）。

@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的序列化设置，而是仅使用符合ISO-8601的时区偏移量。

行为可以使用SerializationFeature.WRITE_DATES_WITH_ZONE_ID进行更改

Answer 11

/sf/answers/3727606851/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/sf/answers/2454397711/一样简单

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

Answer 12

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。