我创建了小型 JPA 项目来保存学生记录。我使用 Oracle 数据库。我使用 OpenJPA 作为 JPa 提供程序。

我已经正确创建了 Table student 和相关序列。

学生实体类

@Entity
@Table(name = "Student")
public class Student implements Serializable {

    private int id;
    private String name;
    private static final long serialVersionUID = 1L;

    public Student() {
        super();
    }

    @Id
    @Column(name = "ID")
    @SequenceGenerator(name = "TRAIN_SEQ", sequenceName = "STUDENT_SEQ")
    @GeneratedValue(strategy = GenerationType.SEQUENCE, generator = "TRAIN_SEQ")
    public int getId() {
        return this.id;
    }

    public void setId(int id) {
        this.id = id;
    }

    @Column(name = "NAME")
    public String getName() {
        return this.name;
    }

    public void setName(String name) {
        this.name = name;
    }

persistence.xml

<?xml version="1.0" encoding="UTF-8"?>
<persistence version="2.0"
    xmlns="http://java.sun.com/xml/ns/persistence" xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
    xsi:schemaLocation="http://java.sun.com/xml/ns/persistence http://java.sun.com/xml/ns/persistence/persistence_2_0.xsd">

    <persistence-unit name="JPAOracleDemo">

        <provider>org.apache.openjpa.persistence.PersistenceProviderImpl</provider>

        <class>com.jpa.demo.model.Student</class>

        <properties>
             <property name="openjpa.ConnectionURL" value="jdbc:oracle:thin:@TEST:50111:TESTPEGAD1" />
            <property name="openjpa.ConnectionDriverName" value="oracle.jdbc.driver.OracleDriver" />
            <property name="openjpa.ConnectionUserName" value="admin" />
            <property name="openjpa.ConnectionPassword" value="admin" />
            <property name="openjpa.RuntimeUnenhancedClasses" value="supported" />
            <property name="openjpa.jdbc.Schema" value="MYSCHEMA" />
        </properties>

    </persistence-unit>

</persistence>

客户端类

OpenJPAEntityManager em = JPAUtil.getEntityManager();
        OpenJPAEntityTransaction tx = em.getTransaction();
        tx.begin();

        // Create the instance of Employee Entity class
        Student student = new Student();
        student.setName("A.Ramesh");

        // JPA API to store the Student instance on the database.
        em.persist(student);
        tx.commit();
        em.close();

        System.out.println("Done...");

实用类

private static OpenJPAEntityManagerFactory emf = OpenJPAPersistence
            .createEntityManagerFactory("JPAOracleDemo", "META-INF/persistence.xml");

    private static OpenJPAEntityManager entManager;

    /**
     * No need to create any instance for this Util.
     */
    private JPAUtil() {
    }

    /**
     * Get {@link EntityManager}.
     * 
     * @return the {@link EntityManager}
     */
    public static OpenJPAEntityManager getEntityManager() {

        if (entManager == null || !entManager.isOpen()) {
            entManager = emf.createEntityManager();
        }

        return entManager;
    }

数据成功持久化到student表，但是出现如下错误

Exception in thread "Attachment 60230" java.lang.UnsupportedOperationException: cannot get the capability, performing dispose of the retransforming environment
    at com.ibm.tools.attach.javaSE.Attachment.loadAgentLibraryImpl(Native Method)
    at com.ibm.tools.attach.javaSE.Attachment.loadAgentLibrary(Attachment.java:253)
    at com.ibm.tools.attach.javaSE.Attachment.parseLoadAgent(Attachment.java:235)
    at com.ibm.tools.attach.javaSE.Attachment.doCommand(Attachment.java:154)
    at com.ibm.tools.attach.javaSE.Attachment.run(Attachment.java:116)
Exception in thread "main" java.lang.UnsupportedOperationException: cannot get the capability, performing dispose of the retransforming environment
    at sun.instrument.InstrumentationImpl.isRetransformClassesSupported0(Native Method)
    at sun.instrument.InstrumentationImpl.isRetransformClassesSupported(InstrumentationImpl.java:124)
    at sun.reflect.NativeMethodAccessorImpl.invoke0(Native Method)
    at sun.reflect.NativeMethodAccessorImpl.invoke(NativeMethodAccessorImpl.java:48)
    at sun.reflect.DelegatingMethodAccessorImpl.invoke(DelegatingMethodAccessorImpl.java:37)
    at java.lang.reflect.Method.invoke(Method.java:600)
    at org.apache.openjpa.enhance.ClassRedefiner.canRedefineClasses(ClassRedefiner.java:123)
    at org.apache.openjpa.enhance.ManagedClassSubclasser.prepareUnenhancedClasses(ManagedClassSubclasser.java:122)
    at org.apache.openjpa.kernel.AbstractBrokerFactory.loadPersistentTypes(AbstractBrokerFactory.java:304)
    at org.apache.openjpa.kernel.AbstractBrokerFactory.initializeBroker(AbstractBrokerFactory.java:228)
    at org.apache.openjpa.kernel.AbstractBrokerFactory.newBroker(AbstractBrokerFactory.java:202)
    at org.apache.openjpa.kernel.DelegatingBrokerFactory.newBroker(DelegatingBrokerFactory.java:156)
    at org.apache.openjpa.persistence.EntityManagerFactoryImpl.createEntityManager(EntityManagerFactoryImpl.java:213)
    at com.ibm.ws.persistence.EntityManagerFactoryImpl.createEntityManager(EntityManagerFactoryImpl.java:45)
    at com.ibm.ws.persistence.EntityManagerFactoryImpl.createEntityManager(EntityManagerFactoryImpl.java:30)
    at com.jpa.demo.util.JPAUtil.getEntityManager(JPAUtil.java:32)
    at com.jpa.demo.client.JPAClient.main(JPAClient.java:13)
1045  JPAOracleDemo  INFO   [main] openjpa.Enhance - Creating subclass for "[class com.jpa.demo.model.Student]". This means that your application will be less efficient and will consume more memory than it would if you ran the OpenJPA enhancer. Additionally, lazy loading will not be available for one-to-one and many-to-one persistent attributes in types using field access; they will be loaded eagerly instead.
Done...

Java 版本

JDK 1.6

有人请告诉我这里的问题是什么吗？

更新:

我使用 IBM Rational Software Architect for Websphere Software 来进行此开发。这个问题出在这个 IDE 上。默认情况下，当我创建 JPA 项目时，它会添加 IBM jre。我刚刚删除了 IBM jre 并尝试使用 SUN jre 然后它成功了。请告诉我为什么这个功能不支持 IBM jre？

最佳答案

<property name="openjpa.RuntimeUnenhancedClasses" value="supported" />

首先，摆脱那个属性。

关于java - 获取 "java.lang.UnsupportedOperationException:"，我们在Stack Overflow上找到一个类似的问题： https://stackoverflow.com/questions/17039009/