JDO双向一对多关系添加对象

时间：2014-02-17 23:43:31

标签： java google-app-engine jdo datanucleus google-cloud-sql

我有一个类Autor和一个类Dokument，它们处于双向1到n列表关系（1个Autor可以编写几个文档），我想将它们保存到Cloud SQL中。 orm在package.jdo和package-cloudsql.orm中指定。

Dokument类：

public class Autor {

    private String aid;

    private String vorname;

    private String nachname;

    private List<Dokument> dokumente;

    public Autor() {

    }

    public Autor(String vorname, String nachname) {
        this.vorname = vorname;
        this.nachname = nachname;
        this.dokumente = new ArrayList<Dokument>();
    }

    public String getAID() {
        return aid;
    }

    public String getVorname() {
        return vorname;
    }

    public String getNachname() {
        return nachname;
    }

    public List<Dokument> getDokumente() {
        return this.dokumente;
    }

    public void setAID(String aid) {
        this.aid = aid;
    }

    public void setVorname(String vorname) {
        this.vorname = vorname;
    }

    public void setNachname(String nachname) {
        this.nachname = nachname;
    }

    public void addDokument(Dokument dokument) {
        this.dokumente.add(dokument);
    }

    public void deleteDokument(Dokument dokument) {
        this.dokumente.remove(dokument);
    }

    public void deleteAllDokumente() {
        this.dokumente.clear();
    }

}

Dokument类：

public class Dokument {

    private String did;

    private Autor autor;

    private String titel;

    private String text;

    private Date datum;

    public Dokument() {

    }

    public Dokument(Autor autor, String titel, String text, Date datum) {
        this.autor = autor;
        this.titel = titel;
        this.text = text;
        this.datum = datum;
    }

    public Dokument(String titel, String text, Date datum) {
        this.autor = null;
        this.titel = titel;
        this.text = text;
        this.datum = datum;
    }

    public String getDid() {
        return did;
    }

    public Autor getAutor() {
        return autor;
    }

    public String getTitel() {
        return titel;
    }

    public String getText() {
        return text;
    }

    public Date getDatum() {
        return datum;
    }

    public void setDID(String did) {
        this.did = did;
    }

    public void setAutor(Autor autor) {
        this.autor = autor;
    }

    public void setTitel(String titel) {
        this.titel = titel;
    }

    public void setText(String text) {
        this.text = text;
    }

    public void setDatum(Date date) {
        this.datum = date;
    }
}

package.jdo包含：

<class name="Autor" detachable="true" identity-type="application">
            <field name="aid" primary-key="true" persistence-modifier="persistent" value-strategy="identity"/>
            <field name="vorname"/>
            <field name="nachname" />
            <field name="dokumente"/>       
        </class>
        <class name="Dokument" detachable="true" identity-type="application">
            <field name="did" primary-key="true" persistence-modifier="persistent" value-strategy="identity"/>
            <field name="autor"/>
            <field name="titel"/>
            <field name="text"/>
            <field name="datum"/>
        </class>

package-sql.orm包含：

<class name="Autor" detachable="true" persistence-modifier="persistence-capable" table="Autor">
            <field name="aid" primary-key="true" persistence-modifier="persistent" value-strategy="identity">
                <column name="aid" jdbc-type="bigint" length="20"/>
            </field>
            <field name="vorname" persistence-modifier="persistent">
                <column name="vorname"/>
            </field>    
            <field name="nachname" persistence-modifier="persistent">
                <column name="nachname"/>
            </field>
            <field name="dokumente" persistence-modifier="persistent" mapped-by="autor">
                <collection element-type="de.hdm.studienarbeit3.dokumente.Dokument"/>
            </field>
        </class>
        <class name="Dokument" detachable="true" persistence-modifier="persistence-capable" table="Dokument">
            <field name="did" primary-key="true" persistence-modifier="persistent" value-strategy="identity">
                <column name="did" jdbc-type="bigint" length="20" />
            </field>
            <field name="autor" persistence-modifier="persistent" default-fetch-group="true">
                <column name="autor" jdbc-type="bigint" length="20"/>
                <foreign-key name="DOKUMENTAUTOR_FK" delete-action="restrict"/>
            </field>
            <field name="titel" persistence-modifier="persistent">
                <column name="titel"/>
            </field>
            <field name="text" persistence-modifier="persistent">
                <column name="text"/>
            </field>
            <field name="datum" persistence-modifier="persistent">
                <column name="datum"/>
            </field>
        </class>

所以我想在现有的Autor中添加第二个（第三个等等）Dokument。但每次我坚持一个Dokument，它也创造了一个新的Autor，我选择了Autor的属性。 例如，我有一个名为“Hans Maier”的Autor，并希望与他一起制作另一个Dokument作为Autor，但新的dokument将有一个id为2的Autor，以及名称为“Hans Maier”的东西。我希望新的文件也可以连接到Autor 1。

我的servlet中有这段代码：

if (autoraid=="") {
  if (vorname == "" | nachname =="") {
    resp.getWriter().println("Bitte Autor auswählen oder Namen vollständig ausfüllen.");
  } else {
     Autor autor = new Autor(vorname, nachname);
     Dokument dokument = new Dokument(autor, titel, text, datum);
     autor.addDokument(dokument);
     DokumentDAO dokumentDao = new DokumentDAO(pmf);
     dokumentDao.addDokument(autor, dokument);
 }
} else {
    AutorDAO autorDao = new AutorDAO(pmf);
    Autor autor = autorDao.getAutor(autoraid);
    Dokument dokument = new Dokument(autor, titel, text, datum);
    autor.addDokument(dokument);
    DokumentDAO dokumentDao = new DokumentDAO(pmf);
    dokumentDao.addDokument(autor, dokument);
}

autorDao.getAutor返回它通过键获取的autor（这个工作）和dokumentDao.addDokument（）使用pm.makePersistent（dokument）保存给定的dokument

我错过了什么或做错了什么？ Datanucleus Documentation说我必须在双向关系http://www.datanucleus.org/products/accessplatform/jdo/orm/relationships.html上使用List时设置两端，我在Dokument创建者和autor.addDokument（）上设置Autor，但它不起作用。

如果我在持久化之前读取了dokument.getAutor（）。getAID（），则返回我希望它连接到的Autor的正确ID，但在数据库中它是一个新的Autor。我怎样才能使它正常工作？

我已经阅读了这个http://www.onjava.com/pub/a/onjava/excerpt/chap_07/index2.html并且createBook方法正是我想要做的，所以我也测试过了

public void addDokument(Autor autor, Dokument dokument) {

    PersistenceManager pm = pmf.getPersistenceManager();
    Transaction tx = pm.currentTransaction();

    try {

      tx.begin();
        dokument.setAutor(autor);
        autor.addDokument(dokument);            
        pm.makePersistent(dokument);

       tx.commit();

    } catch (Exception e) {
      System.out.println("Exception: " + e.getMessage());

    } finally {
      if (tx.isActive()) {
        tx.rollback();
      }
      pm.close();
    }
    }

在交易中，但同样的结果，创建了一个新的Autor。

任何帮助将不胜感激。

日志说明如下：

Feb 18, 2014 1:23:33 PM org.datanucleus.store.rdbms.mapping.MappedTypeManager addMappedType
Schwerwiegend: User-defined type mapping class "org.datanucleus.store.mapped.mapping.LocalDateMapping" was not found. Please check the mapping file class specifications and your CLASSPATH. The class must be in the CLASSPATH.
Feb 18, 2014 1:23:33 PM org.datanucleus.store.rdbms.mapping.MappedTypeManager addMappedType
Schwerwiegend: User-defined type mapping class "org.datanucleus.store.mapped.mapping.LocalDateTimeMapping" was not found. Please check the mapping file class specifications and your CLASSPATH. The class must be in the CLASSPATH.
Feb 18, 2014 1:23:33 PM org.datanucleus.store.rdbms.mapping.MappedTypeManager addMappedType
Schwerwiegend: User-defined type mapping class "org.datanucleus.store.mapped.mapping.LocalTimeMapping" was not found. Please check the mapping file class specifications and your CLASSPATH. The class must be in the CLASSPATH.
Feb 18, 2014 1:23:39 PM org.datanucleus.store.rdbms.query.ForwardQueryResult closingConnection
Information: Reading in results for query "SELECT FROM de.hdm.studienarbeit3.dokumente.Autor ORDER BY nachname asc" since the connection used is closing
Feb 18, 2014 1:23:52 PM org.datanucleus.store.rdbms.mapping.MappedTypeManager addMappedType
Schwerwiegend: User-defined type mapping class "org.datanucleus.store.mapped.mapping.LocalDateMapping" was not found. Please check the mapping file class specifications and your CLASSPATH. The class must be in the CLASSPATH.
Feb 18, 2014 1:23:52 PM org.datanucleus.store.rdbms.mapping.MappedTypeManager addMappedType
Schwerwiegend: User-defined type mapping class "org.datanucleus.store.mapped.mapping.LocalDateTimeMapping" was not found. Please check the mapping file class specifications and your CLASSPATH. The class must be in the CLASSPATH.
Feb 18, 2014 1:23:52 PM org.datanucleus.store.rdbms.mapping.MappedTypeManager addMappedType
Schwerwiegend: User-defined type mapping class "org.datanucleus.store.mapped.mapping.LocalTimeMapping" was not found. Please check the mapping file class specifications and your CLASSPATH. The class must be in the CLASSPATH.

org.datanucleus.store.mapped.mapping。*曾经在datanucleus-core（至少在版本3.1.3中），但现在在版本3.2.9中。它不在了吗？它去了哪里？ datanucleus-rdbms也是版本3.2.9。

System.getProperty（“java.class.path”）

的输出 
[workspace]\studienarbeit3\war\WEB-INF\classes
[workspace]\studienarbeit3\war\WEB-INF\lib\mysql-connector-java-5.1.28-bin.jar
[eclipse]\plugins\com.google.appengine.eclipse.sdkbundle_1.8.9\appengine-java-sdk-1.8.9\lib\shared\appengine-local-runtime-shared.jar
[eclipse]\plugins\com.google.appengine.eclipse.sdkbundle_1.8.9\appengine-java-sdk-1.8.9\lib\shared\el-api.jar
[eclipse]\plugins\com.google.appengine.eclipse.sdkbundle_1.8.9\appengine-java-sdk-1.8.9\lib\shared\jsp\repackaged-appengine-ant-1.7.1.jar
[eclipse]\plugins\com.google.appengine.eclipse.sdkbundle_1.8.9\appengine-java-sdk-1.8.9\lib\shared\jsp\repackaged-appengine-ant-launcher-1.7.1.jar
[eclipse]\plugins\com.google.appengine.eclipse.sdkbundle_1.8.9\appengine-java-sdk-1.8.9\lib\shared\jsp\repackaged-appengine-jasper-6.0.29.jar
[eclipse]\plugins\com.google.appengine.eclipse.sdkbundle_1.8.9\appengine-java-sdk-1.8.9\lib\shared\jsp\repackaged-appengine-jasper-el-6.0.29.jar
[eclipse]\plugins\com.google.appengine.eclipse.sdkbundle_1.8.9\appengine-java-sdk-1.8.9\lib\shared\jsp\repackaged-appengine-tomcat-juli-6.0.29.jar
[eclipse]\plugins\com.google.appengine.eclipse.sdkbundle_1.8.9\appengine-java-sdk-1.8.9\lib\shared\jsp-api.jar
[eclipse]\plugins\com.google.appengine.eclipse.sdkbundle_1.8.9\appengine-java-sdk-1.8.9\lib\shared\servlet-api.jar
[eclipse]\plugins\com.google.appengine.eclipse.sdkbundle_1.8.9\appengine-java-sdk-1.8.9\lib\appengine-tools-api.jar
[eclipse]\plugins\com.google.appengine.eclipse.sdkbundle_1.8.9\appengine-java-sdk-1.8.9\lib\opt\user\appengine-api-labs\v1\appengine-api-labs.jar
[eclipse]\plugins\com.google.appengine.eclipse.sdkbundle_1.8.9\appengine-java-sdk-1.8.9\lib\opt\user\appengine-endpoints\v1\appengine-endpoints-deps.jar
[eclipse]\plugins\com.google.appengine.eclipse.sdkbundle_1.8.9\appengine-java-sdk-1.8.9\lib\opt\user\appengine-endpoints\v1\appengine-endpoints.jar
[eclipse]\plugins\com.google.appengine.eclipse.sdkbundle_1.8.9\appengine-java-sdk-1.8.9\lib\opt\user\jsr107\v1\appengine-jsr107cache-1.8.9.jar
[eclipse]\plugins\com.google.appengine.eclipse.sdkbundle_1.8.9\appengine-java-sdk-1.8.9\lib\opt\user\jsr107\v1\jsr107cache-1.1.jar
[eclipse]\plugins\com.google.appengine.eclipse.sdkbundle_1.8.9\appengine-java-sdk-1.8.9\lib\user\appengine-api-1.0-sdk-1.8.9.jar
[eclipse]\plugins\com.google.appengine.eclipse.sdkbundle_1.8.9\appengine-java-sdk-1.8.9\lib\opt\user\datanucleus\v3\asm-4.0.jar
[eclipse]\plugins\com.google.appengine.eclipse.sdkbundle_1.8.9\appengine-java-sdk-1.8.9\lib\opt\user\datanucleus\v3\datanucleus-api-jdo-3.2.8.jar
[eclipse]\plugins\com.google.appengine.eclipse.sdkbundle_1.8.9\appengine-java-sdk-1.8.9\lib\opt\user\datanucleus\v3\datanucleus-appengine-3.0.0.jar
[eclipse]\plugins\com.google.appengine.eclipse.sdkbundle_1.8.9\appengine-java-sdk-1.8.9\lib\opt\user\datanucleus\v3\datanucleus-core-3.2.9.jar
[eclipse]\plugins\com.google.appengine.eclipse.sdkbundle_1.8.9\appengine-java-sdk-1.8.9\lib\opt\user\datanucleus\v3\datanucleus-rdbms-3.2.9.jar
[eclipse]\plugins\com.google.appengine.eclipse.sdkbundle_1.8.9\appengine-java-sdk-1.8.9\lib\opt\user\datanucleus\v3\jdo-api-3.1-rc1.jar
[eclipse]\plugins\com.google.appengine.eclipse.sdkbundle_1.8.9\appengine-java-sdk-1.8.9\lib\opt\user\datanucleus\v3\jta-1.1.jar
[workspace]\studienarbeit3\war\WEB-INF\lib\javax.servlet.jsp.jstl-1.2.1.jar
[workspace]\studienarbeit3\war\WEB-INF\lib\javax.servlet.jsp.jstl-api-1.2.1.jar
[eclipse]\plugins\com.google.appengine.eclipse.sdkbundle_1.8.9\appengine-java-sdk-1.8.9\lib\impl\google_sql.jar
[eclipse]\plugins\com.google.appengine.eclipse.sdkbundle_1.8.9\appengine-java-sdk-1.8.9\lib\agent\appengine-agent.jar

1 个答案:

答案 0 :(得分：0)

正如Google's compatibility doc所说，他们的GAE /数据存储插件（datanucleus-appengine）仅与DataNucleus 3.1兼容。在DataNucleus Maven回购中有一个build的插件的SVN（与DataNucleus 3.2 / 3.3一起使用）（但是问Google为什么他们懒得发布这个，它已经在他们的SVN中使用了一年或更长时间）。您的其他主题表示您需要DataNucleus 3.2+才能与Google Cloud SQL一起使用。总之，为什么你不能混合和匹配DataNucleus jar版本是非常明显的;选择你正在使用的版本并获得适当的罐子。

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