java Instant is NOT getting serialized as milliseconds using jackson

问题

I am using jackson dependencies for serializing my request object which contains some Java Instant fields.

Following are my mavan dependencies for Jackson

<!-- jackson dependecies -->
    <dependency>
      <groupId>com.fasterxml.jackson.datatype</groupId>
      <artifactId>jackson-datatype-jsr310</artifactId>
      <version>2.8.5</version>
    </dependency>
    <dependency>
        <groupId>com.fasterxml.jackson.core</groupId>
        <artifactId>jackson-core</artifactId>
        <version>2.8.5</version>
    </dependency>
    <dependency>
        <groupId>com.fasterxml.jackson.core</groupId>
        <artifactId>jackson-databind</artifactId>
        <version>2.8.5</version>
    </dependency>
    <dependency>
        <groupId>com.fasterxml.jackson.core</groupId>
        <artifactId>jackson-annotations</artifactId>
        <version>2.8.5</version>
    </dependency>
    <dependency>
        <groupId>com.fasterxml.jackson.jaxrs</groupId>
        <artifactId>jackson-jaxrs-json-provider</artifactId>
        <version>2.8.5</version>
    </dependency>
    <dependency>
         <groupId>com.fasterxml.jackson.datatype</groupId>
        <artifactId>jackson-datatype-jdk8</artifactId>
        <version>2.8.5</version>
    </dependency>
    <!-- Jackson dependencies end -->

I am calling RESTful service from my code using jaxrs, below are corresponding maven dependencies.

<!-- Jersey RESTful Services -->
        <dependency>
            <groupId>org.glassfish.jersey.ext</groupId>
            <artifactId>jersey-spring3</artifactId>
            <version>2.15</version>
            <exclusions>
                <exclusion>
                    <groupId>org.springframework</groupId>
                    <artifactId>spring-core</artifactId>
                </exclusion>
                <exclusion>
                    <groupId>org.springframework</groupId>
                    <artifactId>spring-web</artifactId>
                </exclusion>
                <exclusion>
                    <groupId>org.springframework</groupId>
                    <artifactId>spring-beans</artifactId>
                </exclusion>
            </exclusions>
        </dependency>
        <!-- Jersey json -->
        <dependency>
            <groupId>org.glassfish.jersey.media</groupId>
            <artifactId>jersey-media-json-jackson</artifactId>
            <version>2.15</version>
        </dependency>
    <!-- End  -->

We use Apache shaded jar to put all the jars into single shaded jar. we use Java8 to run the shaded jar. When serializing the objects the java Instant is not getting serialized as milliseconds but nanoseconds. i.e.

"busDate":{"nano":0,"epochSecond":1482796800} instead of
"busDate":1482796800

We are setting below global settings on ObjectMapper class.

private static ObjectMapper staticMaper;

static {
    staticMaper = new ObjectMapper();
    staticMaper.findAndRegisterModules();
    staticMaper.setSerializationInclusion(Include.NON_NULL);
    staticMaper.disable(SerializationFeature.WRITE_DATE_TIMESTAMPS_AS_NANOSECONDS);
    staticMaper.enable(SerializationFeature.WRITE_ENUMS_USING_TO_STRING);
    staticMaper.disable(DeserializationFeature.READ_DATE_TIMESTAMPS_AS_NANOSECONDS);
    staticMaper.enable(DeserializationFeature.READ_ENUMS_USING_TO_STRING);
    staticMaper.disable(DeserializationFeature.FAIL_ON_UNKNOWN_PROPERTIES);
    staticMaper.enable(JsonGenerator.Feature.ESCAPE_NON_ASCII);
}

can someone please help me in resolving this issue.

回答1:

I have added the below line in my code.

objectMapper.registerModule(new JavaTimeModule()); Looks like sometimes this line --> objectMapper.findAndRegisterModules(); does not work as expected.

来源：https://stackoverflow.com/questions/41471890/java-instant-is-not-getting-serialized-as-milliseconds-using-jackson