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我一直在尝试升级我的 JHipster 5 应用程序以使用 Java 10，但我无法让它使用 Maven 编译和处理 JPA 静态元模型。

显然maven-compiler-plugin不是hibernate-jpamodelgen为了生成 JPA 静态元模型而触发。

为了升级项目，我有：

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• 安装Oracle\xc2\xb4s JDK 10.0.1
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• 将我的 pom.xml 切换为<java.version>10</java.version>
\n

• 升级了 maven-compiler-plugin 以添加java.xml.bind模块（因为从 Java 10 开始默认不包含该模块），如下所示：

  \n\n

      <plugin>\n        <groupId>org.apache.maven.plugins</groupId>\n        <artifactId>maven-compiler-plugin</artifactId>\n        <version>${maven-compiler-plugin.version}</version>\n        <configuration>\n            <!-- fork is needed so compiler args can be used -->\n            <fork>true</fork>\n            <compilerArgs>\n                <arg>-J--add-modules</arg>\n                <arg>-Jjava.xml.bind</arg>\n            </compilerArgs>\n            <annotationProcessorPaths>\n                <path>\n                    <groupId>org.mapstruct</groupId>\n                    <artifactId>mapstruct-processor</artifactId>\n                    <version>${mapstruct.version}</version>\n                </path>\n                <!-- For JPA static metamodel generation -->\n                <path>\n                    <groupId>org.hibernate</groupId>\n                    <artifactId>hibernate-jpamodelgen</artifactId>\n                    <version>${hibernate.version}</version>\n                </path>\n\n            </annotationProcessorPaths>\n …

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我需要在Avro架构中将'null'默认值添加到logicalType：'date'。我当前的定义是这样的：

{
 "type": "record",
 "namespace": "my.model.package",
 "name": "Person",
 "version": "1",
 "fields": [
    {"name":"birthday","type": { "type": "int", "logicalType": "date"}}
 ]
}

当我用'birthday'字段填充时，org.joda.time.LocalDate它确实起作用，但是当我离开它时null，出现以下异常：

org.apache.kafka.common.errors.SerializationException: Error serializing Avro message
Caused by: java.lang.NullPointerException: null of int of my.model.package.Person
at org.apache.avro.generic.GenericDatumWriter.npe(GenericDatumWriter.java:145)
at org.apache.avro.generic.GenericDatumWriter.writeWithoutConversion(GenericDatumWriter.java:139)
at org.apache.avro.generic.GenericDatumWriter.write(GenericDatumWriter.java:75)
at org.apache.avro.generic.GenericDatumWriter.write(GenericDatumWriter.java:62)
at io.confluent.kafka.serializers.AbstractKafkaAvroSerializer.serializeImpl(AbstractKafkaAvroSerializer.java:92)
at io.confluent.kafka.serializers.KafkaAvroSerializer.serialize(KafkaAvroSerializer.java:53)
at org.apache.kafka.clients.producer.KafkaProducer.doSend(KafkaProducer.java:459)
at org.apache.kafka.clients.producer.KafkaProducer.send(KafkaProducer.java:436)
...

我尝试了多种方法将此“ logicalType”配置为可为空，但无法使其正常工作。如何将该字段配置为可为空？