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编辑：解决方案： 升级到 ISIS 1.17.0 并设置属性isis.persistor.datanucleus.standaloneCollection.bulkLoad=false解决了前两个问题。

我正在使用 Apache ISIS 1.16.2，并尝试将 Blob/Clob 内容存储在MariaDB数据库 (v10.1.35) 中。因此，我使用 DB 连接器org.mariadb.jdbc.mariadb-java-client(v2.3.0) 并在代码@Persistent中使用许多示例和 ISIS 文档中所示的注释。

使用下面的代码，我只得到一个名为的列content_name（其中 Blob 对象以二进制形式序列化），而不是三列content_name,content_mimetype和content_bytes.

这是带有 Blob 字段的Documentcontent类：

@PersistenceCapable(identityType = IdentityType.DATASTORE)
@DatastoreIdentity(strategy = IdGeneratorStrategy.IDENTITY, column = "id")
@DomainObject(editing = Editing.DISABLED, autoCompleteRepository = DocumentRepository.class, objectType = "Document")
@Getter
// ...
public class Document implements Comparable<Document> {

    @Persistent(
        defaultFetchGroup = "false",
        columns = {
            @Column(name = "content_name"),
            @Column(name = "content_mimetype"),
            @Column(name = "content_bytes",
                jdbcType = "BLOB",
                sqlType = "LONGVARBINARY")
            })
    @Nonnull
    @Column(allowsNull = "false")
    @Property(optionality = Optionality.MANDATORY)
    private Blob content;

    // ...

    @Column(allowsNull = "false")
    @Property
    private Date created = new Date();

    public Date defaultCreated() {
        return new Date();
    }

    @Column(allowsNull = "true")
    @Property
    @Setter
    private String owner;

    // ...
}

这将为 DomainObject 类创建以下架构，Document其中 Blob 字段只有一列：

CREATE TABLE `document` (
  `id` bigint(20) NOT NULL AUTO_INCREMENT,
  `content_name` mediumblob,
  `created` timestamp NOT NULL DEFAULT CURRENT_TIMESTAMP ON UPDATE CURRENT_TIMESTAMP,
  `owner` varchar(255) CHARACTER SET latin1 COLLATE latin1_bin DEFAULT NULL,
  PRIMARY KEY (`id`)
) ENGINE=InnoDB DEFAULT CHARSET=latin1;

通常，org.apache.isis.objectstore.jdo.datanucleus.valuetypes.IsisBlobMappingISIS 框架的类应该进行映射。但似乎这个 Mapper 不知何故没有参与......

1. 问题：如何将 Blob 字段分成三列（如上所述以及在许多演示项目中）。即使我切换到 HSQLDB，我仍然只能得到一列，所以这可能不是 MariaDB 的问题。

2. 问：如果我在从另一个 DomainObject 类继承的类中使用 Blob/Clob 字段，我经常会得到一个org.datanucleus.exceptions.NucleusException（堆栈跟踪见下文）并且我无法确定它的头部或尾部。处理继承时有哪些潜在的陷阱？为什么我会收到此异常？

3. 问：我需要存储属于域对象的文档（您可能已经猜到了）。这样做的正确方法是将文档存储在文件系统树而不是数据库中（默认情况下，数据库也对对象数据有一些大小限制）并引用对象中的文件。在Datanucleus 文档中，我找到了serializeToFileLocation应该做到这一点的扩展。我通过将行添加@Extension(vendorName="datanucleus", key="serializeToFileLocation" value="document-repository")到 Blob 字段来尝试它，但没有发生任何事情。所以我的问题是：这个 Datanucleus 扩展是否与 Apache Isis 兼容？

javax.jdo.listener.StoreLifecycleListener如果此扩展与 Isis 冲突，是否可以org.apache.isis.applib.AbstractSubscriber在将域对象持久保存到数据库并在加载之前将其还原之前将 Blob 存储在文件系统上？有没有更好的解决方案？

现在就是这样。先感谢您！;-)

问题2的堆栈跟踪：

... (other Wicket related stack trace)
Caused by: org.datanucleus.exceptions.NucleusException: Creation of SQLExpression for mapping "org.datanucleus.store.rdbms.mapping.java.SerialisedMapping" caused error
        at org.datanucleus.store.rdbms.sql.expression.SQLExpressionFactory.newExpression(SQLExpressionFactory.java:199)
        at org.datanucleus.store.rdbms.sql.expression.SQLExpressionFactory.newExpression(SQLExpressionFactory.java:155)
        at org.datanucleus.store.rdbms.request.LocateBulkRequest.getStatement(LocateBulkRequest.java:158)
        at org.datanucleus.store.rdbms.request.LocateBulkRequest.execute(LocateBulkRequest.java:283)
        at org.datanucleus.store.rdbms.RDBMSPersistenceHandler.locateObjects(RDBMSPersistenceHandler.java:564)
        at org.datanucleus.ExecutionContextImpl.findObjects(ExecutionContextImpl.java:3313)
        at org.datanucleus.api.jdo.JDOPersistenceManager.getObjectsById(JDOPersistenceManager.java:1850)
        at org.apache.isis.core.runtime.system.persistence.PersistenceSession.loadPersistentPojos(PersistenceSession.java:1010)
        at org.apache.isis.core.runtime.system.persistence.PersistenceSession.adaptersFor(PersistenceSession.java:1603)
        at org.apache.isis.core.runtime.system.persistence.PersistenceSession.adaptersFor(PersistenceSession.java:1573)
        at org.apache.isis.viewer.wicket.model.models.EntityCollectionModel$Type$1.loadInBulk(EntityCollectionModel.java:107)
        at org.apache.isis.viewer.wicket.model.models.EntityCollectionModel$Type$1.load(EntityCollectionModel.java:93)
        at org.apache.isis.viewer.wicket.model.models.EntityCollectionModel.load(EntityCollectionModel.java:454)
        at org.apache.isis.viewer.wicket.model.models.EntityCollectionModel.load(EntityCollectionModel.java:70)
        at org.apache.wicket.model.LoadableDetachableModel.getObject(LoadableDetachableModel.java:135)
        at org.apache.isis.viewer.wicket.ui.components.collectioncontents.ajaxtable.CollectionContentsSortableDataProvider.size(CollectionContentsSortableDataProvider.java:68)
        at org.apache.wicket.markup.repeater.data.DataViewBase.internalGetItemCount(DataViewBase.java:142)
        at org.apache.wicket.markup.repeater.AbstractPageableView.getItemCount(AbstractPageableView.java:235)
        at org.apache.wicket.markup.repeater.AbstractPageableView.getRowCount(AbstractPageableView.java:216)
        at org.apache.wicket.markup.repeater.AbstractPageableView.getViewSize(AbstractPageableView.java:314)
        at org.apache.wicket.markup.repeater.AbstractPageableView.getItemModels(AbstractPageableView.java:99)
        at org.apache.wicket.markup.repeater.RefreshingView.onPopulate(RefreshingView.java:93)
        at org.apache.wicket.markup.repeater.AbstractRepeater.onBeforeRender(AbstractRepeater.java:124)
        at org.apache.wicket.markup.repeater.AbstractPageableView.onBeforeRender(AbstractPageableView.java:115)
        at org.apache.wicket.Component.internalBeforeRender(Component.java:950)
        at org.apache.wicket.Component.beforeRender(Component.java:1018)
        at org.apache.wicket.MarkupContainer.onBeforeRenderChildren(MarkupContainer.java:1825)
        ... 81 more
 Caused by: org.datanucleus.exceptions.NucleusException: Unable to create SQLExpression for mapping of type "org.datanucleus.store.rdbms.mapping.java.SerialisedMapping" since not supported
        at org.datanucleus.store.rdbms.sql.expression.SQLExpressionFactory#newExpression(SQLExpressionFactory.java:189)
        at org.datanucleus.store.rdbms.sql.expression.SQLExpressionFactory#newExpression(SQLExpressionFactory.java:155)
        at org.datanucleus.store.rdbms.request.LocateBulkRequest#getStatement(LocateBulkRequest.java:158)
        at org.datanucleus.store.rdbms.request.LocateBulkRequest#execute(LocateBulkRequest.java:283)
        at org.datanucleus.store.rdbms.RDBMSPersistenceHandler#locateObjects(RDBMSPersistenceHandler.java:564)
        at org.datanucleus.ExecutionContextImpl#findObjects(ExecutionContextImpl.java:3313)
        at org.datanucleus.api.jdo.JDOPersistenceManager#getObjectsById(JDOPersistenceManager.java:1850)
        at org.apache.isis.core.runtime.system.persistence.PersistenceSession#loadPersistentPojos(PersistenceSession.java:1010)
        at org.apache.isis.core.runtime.system.persistence.PersistenceSession#adaptersFor(PersistenceSession.java:1603)
        at org.apache.isis.core.runtime.system.persistence.PersistenceSession#adaptersFor(PersistenceSession.java:1573)
        at org.apache.isis.viewer.wicket.model.models.EntityCollectionModel$Type$1#loadInBulk(EntityCollectionModel.java:107)
        at org.apache.isis.viewer.wicket.model.models.EntityCollectionModel$Type$1#load(EntityCollectionModel.java:93)
        at org.apache.isis.viewer.wicket.model.models.EntityCollectionModel#load(EntityCollectionModel.java:454)
        at org.apache.isis.viewer.wicket.model.models.EntityCollectionModel#load(EntityCollectionModel.java:70)
        at org.apache.wicket.model.LoadableDetachableModel#getObject(LoadableDetachableModel.java:135)
        at org.apache.isis.viewer.wicket.ui.components.collectioncontents.ajaxtable.CollectionContentsSortableDataProvider#size(CollectionContentsSortableDataProvider.java:68)
        at org.apache.wicket.markup.repeater.data.DataViewBase#internalGetItemCount(DataViewBase.java:142)
        at org.apache.wicket.markup.repeater.AbstractPageableView#getItemCount(AbstractPageableView.java:235)
        at org.apache.wicket.markup.repeater.AbstractPageableView#getRowCount(AbstractPageableView.java:216)
        at org.apache.wicket.markup.repeater.AbstractPageableView#getViewSize(AbstractPageableView.java:314)
        at org.apache.wicket.markup.repeater.AbstractPageableView#getItemModels(AbstractPageableView.java:99)
        at org.apache.wicket.markup.repeater.RefreshingView#onPopulate(RefreshingView.java:93)
        at org.apache.wicket.markup.repeater.AbstractRepeater#onBeforeRender(AbstractRepeater.java:124)
        at org.apache.wicket.markup.repeater.AbstractPageableView#onBeforeRender(AbstractPageableView.java:115)
        // <-- 8 times the following lines
        at org.apache.wicket.Component#internalBeforeRender(Component.java:950)
        at org.apache.wicket.Component#beforeRender(Component.java:1018)
        at org.apache.wicket.MarkupContainer#onBeforeRenderChildren(MarkupContainer.java:1825)
        at org.apache.wicket.Component#onBeforeRender(Component.java:3916)
        // -->
        at org.apache.wicket.Page#onBeforeRender(Page.java:801)
        at org.apache.wicket.Component#internalBeforeRender(Component.java:950)
        at org.apache.wicket.Component#beforeRender(Component.java:1018)
        at org.apache.wicket.Component#internalPrepareForRender(Component.java:2236)
        at org.apache.wicket.Page#internalPrepareForRender(Page.java:242)
        at org.apache.wicket.Component#render(Component.java:2325)
        at org.apache.wicket.Page#renderPage(Page.java:1018)
        at org.apache.wicket.request.handler.render.WebPageRenderer#renderPage(WebPageRenderer.java:124)
        at org.apache.wicket.request.handler.render.WebPageRenderer#respond(WebPageRenderer.java:195)
        at org.apache.wicket.core.request.handler.RenderPageRequestHandler#respond(RenderPageRequestHandler.java:175)
        at org.apache.wicket.request.cycle.RequestCycle$HandlerExecutor#respond(RequestCycle.java:895)
        at org.apache.wicket.request.RequestHandlerStack#execute(RequestHandlerStack.java:64)
        at org.apache.wicket.request.cycle.RequestCycle#execute(RequestCycle.java:265)
        at org.apache.wicket.request.cycle.RequestCycle#processRequest(RequestCycle.java:222)
        at org.apache.wicket.request.cycle.RequestCycle#processRequestAndDetach(RequestCycle.java:293)
        at org.apache.wicket.protocol.http.WicketFilter#processRequestCycle(WicketFilter.java:261)
        at org.apache.wicket.protocol.http.WicketFilter#processRequest(WicketFilter.java:203)
        at org.apache.wicket.protocol.http.WicketFilter#doFilter(WicketFilter.java:284)
        at org.eclipse.jetty.servlet.ServletHandler$CachedChain#doFilter(ServletHandler.java:1668)
        at org.apache.isis.core.webapp.diagnostics.IsisLogOnExceptionFilter#doFilter(IsisLogOnExceptionFilter.java:52)
        at org.eclipse.jetty.servlet.ServletHandler$CachedChain#doFilter(ServletHandler.java:1668)
        at org.apache.shiro.web.servlet.AbstractShiroFilter#executeChain(AbstractShiroFilter.java:449)
        at org.apache.shiro.web.servlet.AbstractShiroFilter$1#call(AbstractShiroFilter.java:365)
        at org.apache.shiro.subject.support.SubjectCallable#doCall(SubjectCallable.java:90)
        at org.apache.shiro.subject.support.SubjectCallable#call(SubjectCallable.java:83)
        at org.apache.shiro.subject.support.DelegatingSubject#execute(DelegatingSubject.java:383)
        at org.apache.shiro.web.servlet.AbstractShiroFilter#doFilterInternal(AbstractShiroFilter.java:362)
        at org.apache.shiro.web.servlet.OncePerRequestFilter#doFilter(OncePerRequestFilter.java:125)
        at org.eclipse.jetty.servlet.ServletHandler$CachedChain#doFilter(ServletHandler.java:1668)
        // ... some Jetty stuff
        at java.lang.Thread#run(Thread.java:748)
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1 回答 1

2

经过一番研究，我认为问题1的问题和 2似乎与this ISIS bug report #1902有关。

简而言之：datanucleus 扩展插件解析机制似乎没有找到 ISIS 值类型适配器，因此无法知道如何序列化 ISIS 的 Blob/Clob 类型。

根据前面提到的 ISIS 错误报告，这个问题在 1.17.0 中得到修复，所以我正在尝试从 1.16.2 升级到这个版本（它引入了许多其他问题，但这将是一个额外的话题）。

对于问题 3，我发现Minio基本上解决了我的问题，但它对于我的需要来说有点过大。我将继续寻找将 Blob/Clobs 存储到本地文件系统的其他解决方案，并将记住 Minio...

更新：

  1. 我将我的项目升级到 ISIS 版本 1.17.0。它解决了我在问题 1 中的问题（现在我得到了 Blob/Clob 对象的三列）。
  2. 问题 2 ( NucleusException) 中的问题未通过升级解决。我发现只有在返回带有 Blob/Clob 字段的 DomainObjects 列表时才会抛出它，即如果呈现为独立表。如果我直接进入对象的实体视图，则不会引发异常，并且我可以查看/修改/下载 Blob/Clob 内容。
  3. 与此同时，我编写了自己的 datanucleus 插件，将 Blob/Clobs 作为文件存储在文件系统上。

更新 2

  1. 我找到了绕过org.datanucleus.exceptions.NucleusException: Unable to create SQLExpression for mapping of type "org.apache.isis.objectstore.jdo.datanucleus.valuetypes.IsisClobMapping" since not supported. 批量加载似乎有问题（但我不知道任何细节）。isis.persistor.datanucleus.standaloneCollection.bulkLoad=false通过属性（最初由 ISIS 原型设置）停用批量加载true解决了该问题。
于 2019-04-09T11:50:30.767 回答