java - 使用objectMapper将JSON日期格式反序列化为ZonedDateTime

背景

我有以下JSON(来自Kafka的消息)

{
      "markdownPercentage": 20,
      "currency": "SEK",
      "startDate": "2019-07-25"
}

我有以下(生成的JSON模式)POJO(我无法更改POJO，因为它是公司中的共享资源)

public class Markdown {
    @JsonProperty("markdownPercentage")
    @NotNull
    private Integer markdownPercentage = 0;
    @JsonProperty("currency")
    @NotNull
    private String currency = "";
    @JsonFormat(
        shape = Shape.STRING,
        pattern = "yyyy-MM-dd"
    )
    @JsonProperty("startDate")
    @NotNull
    private ZonedDateTime startDate;

    // Constructors, Getters, Setters etc.

}

我们的应用程序是一个Spring Boot应用程序，它使用Spring Cloud Stream从Kafka读取JSON消息(1)并使用POJO(2)，然后对其进行处理。

问题

当应用程序尝试将消息反序列化到对象时，它将引发以下异常

com.fasterxml.jackson.databind.exc.InvalidFormatException: Cannot deserialize value of type `java.time.ZonedDateTime` from String "2019-07-25": Failed to deserialize java.time.ZonedDateTime: (java.time.DateTimeException) Unable to obtain ZonedDateTime from TemporalAccessor: {},ISO resolved to 2019-07-25 of type java.time.format.Parsed
 at [Source: (String)"{"styleOption":"so2_GreyMelange_1563966403695_1361997740","markdowns":[{"markdownPercentage":20,"currency":"SEK","startDate":"2019-07-25"},{"markdownPercentage":20,"currency":"NOK","startDate":"2019-07-25"},{"markdownPercentage":20,"currency":"CHF","startDate":"2019-07-25"}]}"; line: 1, column: 126] (through reference chain: com.bestseller.generated.interfacecontracts.kafkamessages.pojos.markdownScheduled.MarkdownScheduled["markdowns"]->java.util.ArrayList[0]->com.bestseller.generated.interfacecontracts.kafkamessages.pojos.markdownScheduled.Markdown["startDate"])

    at com.fasterxml.jackson.databind.exc.InvalidFormatException.from(InvalidFormatException.java:67)
    at com.fasterxml.jackson.databind.DeserializationContext.weirdStringException(DeserializationContext.java:1549)
    at com.fasterxml.jackson.databind.DeserializationContext.handleWeirdStringValue(DeserializationContext.java:911)
    at com.fasterxml.jackson.datatype.jsr310.deser.JSR310DeserializerBase._handleDateTimeException(JSR310DeserializerBase.java:80)
    at com.fasterxml.jackson.datatype.jsr310.deser.InstantDeserializer.deserialize(InstantDeserializer.java:212)
    at com.fasterxml.jackson.datatype.jsr310.deser.InstantDeserializer.deserialize(InstantDeserializer.java:50)
    at com.fasterxml.jackson.databind.deser.impl.MethodProperty.deserializeAndSet(MethodProperty.java:127)
    at com.fasterxml.jackson.databind.deser.BeanDeserializer.vanillaDeserialize(BeanDeserializer.java:288)
    at com.fasterxml.jackson.databind.deser.BeanDeserializer.deserialize(BeanDeserializer.java:151)
    at com.fasterxml.jackson.databind.deser.std.CollectionDeserializer.deserialize(CollectionDeserializer.java:286)
    at com.fasterxml.jackson.databind.deser.std.CollectionDeserializer.deserialize(CollectionDeserializer.java:245)
    at com.fasterxml.jackson.databind.deser.std.CollectionDeserializer.deserialize(CollectionDeserializer.java:27)
    at com.fasterxml.jackson.databind.deser.impl.MethodProperty.deserializeAndSet(MethodProperty.java:127)
    at com.fasterxml.jackson.databind.deser.BeanDeserializer.vanillaDeserialize(BeanDeserializer.java:288)
    at com.fasterxml.jackson.databind.deser.BeanDeserializer.deserialize(BeanDeserializer.java:151)
    at com.fasterxml.jackson.databind.ObjectMapper._readMapAndClose(ObjectMapper.java:4013)
    at com.fasterxml.jackson.databind.ObjectMapper.readValue(ObjectMapper.java:3004)
    at com.bestseller.mps.functional.TestingConfiguration.test(TestingConfiguration.java:42)
    at java.base/jdk.internal.reflect.NativeMethodAccessorImpl.invoke0(Native Method)
    at java.base/jdk.internal.reflect.NativeMethodAccessorImpl.invoke(NativeMethodAccessorImpl.java:62)
    at java.base/jdk.internal.reflect.DelegatingMethodAccessorImpl.invoke(DelegatingMethodAccessorImpl.java:43)
    at java.base/java.lang.reflect.Method.invoke(Method.java:566)
    at org.junit.runners.model.FrameworkMethod$1.runReflectiveCall(FrameworkMethod.java:50)
    at org.junit.internal.runners.model.ReflectiveCallable.run(ReflectiveCallable.java:12)
    at org.junit.runners.model.FrameworkMethod.invokeExplosively(FrameworkMethod.java:47)
    at org.junit.internal.runners.statements.InvokeMethod.evaluate(InvokeMethod.java:17)
    at org.junit.runners.ParentRunner.runLeaf(ParentRunner.java:325)
    at org.junit.runners.BlockJUnit4ClassRunner.runChild(BlockJUnit4ClassRunner.java:78)
    at org.junit.runners.BlockJUnit4ClassRunner.runChild(BlockJUnit4ClassRunner.java:57)
    at org.junit.runners.ParentRunner$3.run(ParentRunner.java:290)
    at org.junit.runners.ParentRunner$1.schedule(ParentRunner.java:71)
    at org.junit.runners.ParentRunner.runChildren(ParentRunner.java:288)
    at org.junit.runners.ParentRunner.access$000(ParentRunner.java:58)
    at org.junit.runners.ParentRunner$2.evaluate(ParentRunner.java:268)
    at org.junit.runners.ParentRunner.run(ParentRunner.java:363)
    at org.junit.runner.JUnitCore.run(JUnitCore.java:137)
    at com.intellij.junit4.JUnit4IdeaTestRunner.startRunnerWithArgs(JUnit4IdeaTestRunner.java:68)
    at com.intellij.rt.execution.junit.IdeaTestRunner$Repeater.startRunnerWithArgs(IdeaTestRunner.java:47)
    at com.intellij.rt.execution.junit.JUnitStarter.prepareStreamsAndStart(JUnitStarter.java:242)
    at com.intellij.rt.execution.junit.JUnitStarter.main(JUnitStarter.java:70)
Caused by: java.time.DateTimeException: Unable to obtain ZonedDateTime from TemporalAccessor: {},ISO resolved to 2019-07-25 of type java.time.format.Parsed
    at java.base/java.time.ZonedDateTime.from(ZonedDateTime.java:566)
    at com.fasterxml.jackson.datatype.jsr310.deser.InstantDeserializer.deserialize(InstantDeserializer.java:207)
    ... 35 more
Caused by: java.time.DateTimeException: Unable to obtain ZoneId from TemporalAccessor: {},ISO resolved to 2019-07-25 of type java.time.format.Parsed
    at java.base/java.time.ZoneId.from(ZoneId.java:463)
    at java.base/java.time.ZonedDateTime.from(ZonedDateTime.java:554)
    ... 36 more

当前代码

我定义了以下objectMapper

/**
     * Date mapper.
     *
     * @return the {@link ObjectMapper}
     */
    @Bean
    public ObjectMapper objectMapper() {
        ObjectMapper mapper = new ObjectMapper();
        mapper.registerModule(new JavaTimeModule());
        mapper.setDateFormat(new SimpleDateFormat("yyyy-MM-dd"));
        return mapper;
    }

问题

我知道POJO中生成的ZonedDateTime需要一个“时间”元素，该元素在源消息中不存在。我只能控制objectMapper。有没有可以进行这项工作的可能配置？

注意

如果反序列化POJO中的时间元素被“假定”为startOfDay，即“00.00.00.000Z”，我很好

最佳答案

我只能控制ObjectMapper。有没有可以进行这项工作的可能配置？

只要您对时间和时区的默认值感到满意，就可以使用自定义解串器解决该问题:

public class ZonedDateTimeDeserializer extends JsonDeserializer<ZonedDateTime> {

    @Override
    public ZonedDateTime deserialize(JsonParser jsonParser,
                                     DeserializationContext deserializationContext)
                                     throws IOException {

        LocalDate localDate = LocalDate.parse(
                jsonParser.getText(),
                DateTimeFormatter.ISO_LOCAL_DATE);

        return localDate.atStartOfDay(ZoneOffset.UTC);
    }
}

然后将其添加到模块并将模块注册到您的ObjectMapper实例:

SimpleModule module = new SimpleModule();
module.addDeserializer(ZonedDateTime.class, new ZonedDateTimeDeserializer());

ObjectMapper mapper = new ObjectMapper();
mapper.registerModule(module);

如果将反序列化器添加到模块不适合您(从某种意义上说，此配置将应用于其他ZonedDateTime实例)，那么您可以依靠混合来定义反序列化器将应用于哪些字段。首先定义一个混合界面，如下所示:

public interface MarkdownMixIn {

    @JsonDeserialize(using = ZonedDateTimeDeserializer.class)
    ZonedDateTime getDate();
}

然后将混合接口绑定到所需的类:

ObjectMapper mapper = new ObjectMapper();
mapper.addMixIn(Markdown.class, MarkdownMixIn.class);