JPA 实体解析错误

Question

自从将我的 JavaFX 项目转换为 Maven 项目后，我就无法再访问实体 BenutzerKonversation。我还收到错误消息，当有 2 个或更多主键时需要注释 @IdClass。添加该注释并创建所需的类BenutzerKonversationId 后，我得到了一个ParseError。

经过几次测试，我可以肯定地说它与实体BenutzerKonversation 有关。我的实体是 WebService (JAX-WS) 的一部分。返回实体时，会出现ParseError。实体的输出之前返回是正确的并且包含预期值。

在启动 WebService 时，我还注意到以下 SQL 警告消息：

SQL 警告：

Internal Exception:com.mysql.jdbc.exceptions.jdbc4.MySQLSyntaxErrorException:Table 'benutzer' already exists
Error Code: 1050 
Call: CREATE TABLE BENUTZER (id INTEGER NOT NULL, nachname VARCHAR(255), prueferNr INTEGER, status INTEGER, vorname VARCHAR(255), PRIMARY KEY (id)) 
Query: DataModifyQuery(sql="CREATE TABLE BENUTZER (id INTEGER NOT NULL, nachname VARCHAR(255), prueferNr INTEGER, status INTEGER, vorname VARCHAR(255), PRIMARY KEY (id))")

Persistence.xml：

  <class>entity.Benutzer</class>
  <class>entity.Konversation</class>
  <class>entity.BenutzerKonversation</class>

  <properties>
     <property name="javax.persistence.jdbc.url" value="jdbc:mysql://localhost:3306/projekt8592Db"/>
     <property name="javax.persistence.jdbc.user" value="root"/>
     <property name="javax.persistence.jdbc.password" value=""/>
     <property name="javax.persistence.jdbc.driver" value="com.mysql.jdbc.Driver"/>
     <property name="eclipselink.logging.level" value="FINE"/>
     <property name="eclipselink.ddl-generation" value="create-or-extend-tables"/>
  </properties>

当从 Web 服务查询实体 Benutzer（使用静态 BenutzerService.findById(1) 进行测试）并且数据库中有 BenutzerKonversations 时，我收到以下解析错误：

例外：

javafx.fxml.LoadException:/...Path...View.fxml:13
at javafx.fxml.FXMLLoader.constructLoadException(FXMLLoader.java:2601)
at javafx.fxml.FXMLLoader.loadImpl(FXMLLoader.java:2579)
at javafx.fxml.FXMLLoader.loadImpl(FXMLLoader.java:2441)
at javafx.fxml.FXMLLoader.loadImpl(FXMLLoader.java:3214)
at javafx.fxml.FXMLLoader.loadImpl(FXMLLoader.java:3175)
at javafx.fxml.FXMLLoader.loadImpl(FXMLLoader.java:3148)
at javafx.fxml.FXMLLoader.loadImpl(FXMLLoader.java:3124)
at javafx.fxml.FXMLLoader.loadImpl(FXMLLoader.java:3104)
at javafx.fxml.FXMLLoader.load(FXMLLoader.java:3097)
at application.Main.start(Main.java:14)
at 

com.sun.javafx.application.LauncherImpl.lambda$launchApplication1$162(LauncherImpl.java:863)
    at com.sun.javafx.application.PlatformImpl.lambda$runAndWait$175(PlatformImpl.java:326)
    at com.sun.javafx.application.PlatformImpl.lambda$null$173(PlatformImpl.java:295)
    at java.security.AccessController.doPrivileged(Native Method)
    at com.sun.javafx.application.PlatformImpl.lambda$runLater$174(PlatformImpl.java:294)
    at com.sun.glass.ui.InvokeLaterDispatcher$Future.run(InvokeLaterDispatcher.java:95)
    at com.sun.glass.ui.win.WinApplication._runLoop(Native Method)
    at com.sun.glass.ui.win.WinApplication.lambda$null$148(WinApplication.java:191)
    at java.lang.Thread.run(Thread.java:745)
Caused by: com.sun.xml.internal.ws.encoding.soap.DeserializationException: [failed to localize] Die Antwort konnte nicht deserialisiert werden.(javax.xml.bind.UnmarshalException
 - with linked exception:
[javax.xml.stream.XMLStreamException: ParseError at [row,col]:[1,192]
Message: XML-Dokumentstrukturen müssen innerhalb derselben Entität beginnen und enden.])
    at com.sun.xml.internal.ws.client.sei.SyncMethodHandler.invoke(SyncMethodHandler.java:111)
    at com.sun.xml.internal.ws.client.sei.SyncMethodHandler.invoke(SyncMethodHandler.java:77)
    at com.sun.xml.internal.ws.client.sei.SEIStub.invoke(SEIStub.java:147)
    at com.sun.proxy.$Proxy38.getUserById(Unknown Source)
    at launch.CClient.<init>(CClient.java:28)
    at application.Controller.<init>(Controller.java:62)
    at sun.reflect.NativeConstructorAccessorImpl.newInstance0(Native Method)
    at sun.reflect.NativeConstructorAccessorImpl.newInstance(NativeConstructorAccessorImpl.java:62)
    at sun.reflect.DelegatingConstructorAccessorImpl.newInstance(DelegatingConstructorAccessorImpl.java:45)
    at java.lang.reflect.Constructor.newInstance(Constructor.java:423)
    at java.lang.Class.newInstance(Class.java:442)
    at sun.reflect.misc.ReflectUtil.newInstance(ReflectUtil.java:51)
    at javafx.fxml.FXMLLoader$ValueElement.processAttribute(FXMLLoader.java:927)
    at javafx.fxml.FXMLLoader$InstanceDeclarationElement.processAttribute(FXMLLoader.java:971)
    at javafx.fxml.FXMLLoader$Element.processStartElement(FXMLLoader.java:220)
    at  javafx.fxml.FXMLLoader$ValueElement.processStartElement(FXMLLoader.java:744)
    at javafx.fxml.FXMLLoader.processStartElement(FXMLLoader.java:2707)
    at javafx.fxml.FXMLLoader.loadImpl(FXMLLoader.java:2527)
    ... 17 more
    Caused by: javax.xml.bind.UnmarshalException
     - with linked exception:
    [javax.xml.stream.XMLStreamException: ParseError at [row,col]:[1,192]
    Message: XML-Dokumentstrukturen müssen innerhalb derselben Entität beginnen und enden.]
        at com.sun.xml.internal.bind.v2.runtime.unmarshaller.UnmarshallerImpl.handleStreamException(UnmarshallerImpl.java:470)
        at com.sun.xml.internal.bind.v2.runtime.unmarshaller.UnmarshallerImpl.unmarshal0(UnmarshallerImpl.java:402)
        at com.sun.xml.internal.bind.v2.runtime.BridgeImpl.unmarshal(BridgeImpl.java:109)
        at com.sun.xml.internal.bind.api.Bridge.unmarshal(Bridge.java:222)
        at com.sun.xml.internal.ws.db.glassfish.BridgeWrapper.unmarshal(BridgeWrapper.java:257)
    at com.sun.xml.internal.ws.client.sei.ResponseBuilder$DocLit.readResponse(ResponseBuilder.java:635)
    at com.sun.xml.internal.ws.client.sei.StubHandler.readResponse(StubHandler.java:243)
    at com.sun.xml.internal.ws.db.DatabindingImpl.deserializeResponse(DatabindingImpl.java:189)
    at com.sun.xml.internal.ws.db.DatabindingImpl.deserializeResponse(DatabindingImpl.java:276)
    at com.sun.xml.internal.ws.client.sei.SyncMethodHandler.invoke(SyncMethodHandler.java:104)
    ... 34 more
Caused by: javax.xml.stream.XMLStreamException: ParseError at [row,col]:[1,192]
Message: XML-Dokumentstrukturen müssen innerhalb derselben Entität beginnen und enden.
    at com.sun.org.apache.xerces.internal.impl.XMLStreamReaderImpl.next(XMLStreamReaderImpl.java:596)
    at com.sun.xml.internal.ws.util.xml.XMLStreamReaderFilter.next(XMLStreamReaderFilter.java:81)
    at com.sun.xml.internal.bind.v2.runtime.unmarshaller.StAXStreamConnector.bridge(StAXStreamConnector.java:181)
    at com.sun.xml.internal.bind.v2.runtime.unmarshaller.UnmarshallerImpl.unmarshal0(UnmarshallerImpl.java:400)
    ... 42 more

BenutzerKonversation（多对多实体）：

@Entity
    @Table(name="benutzer_konversation") 
    @IdClass(BenutzerKonversationId.class)
    @NamedQueries({
        @NamedQuery(
                name="BenutzerKonversation.findAll",
                query="SELECT bk FROM BenutzerKonversation bk"
        )
    })

public class BenutzerKonversation {

    @Id
    private int benutzer_id;

    @Id
    private int konversation_id;

    @ManyToOne(cascade=CascadeType.ALL)
    @JoinColumn(name = "benutzer_id",nullable=false, updatable = false, insertable = false)
    private Benutzer benutzer;

    @ManyToOne(cascade=CascadeType.ALL)
    @JoinColumn(name = "konversation_id",nullable=false, updatable = false, insertable = false)
    private Konversation konversation;

    @Column(name="status",nullable=false,updatable=true,insertable=true)
    private int status;
}

Benutzer（实体）

@OneToMany(mappedBy="benutzer",cascade=CascadeType.PERSIST)
private List<BenutzerKonversation> konversationen = new ArrayList<>();

对话（实体）

@OneToMany(mappedBy="konversation",cascade=CascadeType.PERSIST)
private List<BenutzerKonversation> benutzer;

SOAP UI 响应：

<?xml version="1.0" ?>
<S:Envelope xmlns:S="http://schemas.xmlsoap.org/soap/envelope/">
<S:Body><ns2:getUserByIdResponse xmlns:ns2="http://webservice/">
<return><konversationen><benutzer

在查询 BenutzerService.findById(1) 之后，我从 SOAP UI 得到了这个响应。

Answer 1

问题是，我的 DTO（数据传输对象）不完整​​。我意识到，我设置了一个“BenutzerKonversation”的空列表并尝试将其不完整地返回给客户端，这就是问题发生的原因。