如何将 EntityManager 正确注入 JAX-WS Web 服务？

如何解决如何将 EntityManager 正确注入 JAX-WS Web 服务？

我正在尝试实现一个 JAX-WS Web 服务，该服务具有一个端点，该端点从配置的数据源返回数据。我设法创建了服务和客户端，但是我无法访问数据库，因为当我尝试使用注入的 EntityManager 时出现空指针异常。 这是我的服务：

@WebService(serviceName="ViewDocuments")
public class ViewDocumentService {

    @PersistenceContext(unitName = "HibernateJPA")
    private EntityManager em;

    @WebMethod
    public String sayHello() {
        return "Hello world!";
    }

    @Produces("application/json")
    @WebMethod(operationName="getDocuments")
    public List<File> getDocuments(@WebParam(name = "name") String filename) {
        if(filename == null)
            return em.createQuery("FROM File").getResultList();
        else return null;
    }
}

这是我的 WebServiceClient：

@WebServiceClient(name="ViewDocuments",wsdlLocation = "http://localhost:8080/lab8/ViewDocuments?wsdl")
public class ViewDocumentClient extends Service {

    protected ViewDocumentClient(URL wsdlDocumentLocation,QName serviceName) {
        super(wsdlDocumentLocation,serviceName);
    }

    @WebEndpoint(name = "DocumentPort")
    public ViewDocumentService getDocumentPort() {
        return new ViewDocumentService();
    }
}

我试图在这里调用函数：

public class MainDocumentClient {
    public static void main(String[] args) throws Exception {
        URL wsdlUrl = new URL("http://localhost:8080/lab8/ViewDocuments?wsdl");
        QName serviceName = new QName("http://webservices/","ViewDocuments");
        ViewDocumentClient service = new ViewDocumentClient(wsdlUrl,serviceName);
        ViewDocumentService viewDocumentService = service.getDocumentPort();
        System.out.println(viewDocumentService.sayHello());
        System.out.println(viewDocumentService.getDocuments(null));
    }
}

这是我的persistence.xml文件内容：

<?xml version="1.0" encoding="UTF-8"?>
<persistence version="2.2"
             xmlns="http://xmlns.jcp.org/xml/ns/persistence"
             xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
             xsi:schemaLocation="http://xmlns.jcp.org/xml/ns/persistence
     http://xmlns.jcp.org/xml/ns/persistence/persistence_2_2.xsd">

    <persistence-unit name="HibernateJPA" transaction-type="JTA">

        <provider>org.hibernate.jpa.HibernatePersistenceProvider</provider>

        <jta-data-source>java:/Postgres-Source8</jta-data-source>

        <exclude-unlisted-classes>false</exclude-unlisted-classes>

        <properties>
            <property name="hibernate.dialect" value="org.hibernate.dialect.PostgreSQL95Dialect" />
            <property name="hibernate.hbm2ddl.auto" value="create-drop" />
            <property name="hibernate.show_sql" value="true" />
            <property name="hibernate.format_sql" value="true" />
            <property name="hibernate.archive.autodetection" value="class,hbm" />

        </properties>

    </persistence-unit>

    <persistence-unit name="HibernateJPAForTests" transaction-type="RESOURCE_LOCAL">

        <provider>org.hibernate.jpa.HibernatePersistenceProvider</provider>

        <exclude-unlisted-classes>false</exclude-unlisted-classes>

        <properties>
            <property name="javax.persistence.jdbc.url" value="jdbc:postgresql://localhost:5432/lab8" />
            <property name="javax.persistence.jdbc.driver" value="org.postgresql.Driver" />
            <property name="javax.persistence.jdbc.user" value="postgres" />
            <property name="javax.persistence.jdbc.password" value="<password>" />
            <property name="hibernate.dialect" value="org.hibernate.dialect.PostgreSQL95Dialect" />
            <property name="hibernate.hbm2ddl.auto" value="create-drop" />
            <property name="hibernate.show_sql" value="true" />
            <property name="hibernate.format_sql" value="true" />
            <property name="hibernate.archive.autodetection" value="class,hbm" />

        </properties>

    </persistence-unit>
</persistence>

sayHello() 方法工作正常。我还尝试使用 EntityManagerFactory，手动实例化我的 Repository，添加 @Stateless 注释，但似乎没有任何效果。我只是无法查询我的数据库。 经过大量研究，我似乎仍然无法理解如何正确注入 EntityManager。有人可以向我解释一下吗？

我使用的是 Wildfly21.0.0。