java - 访问列表中的对象(Inception)

Question

我有一个对象 WorkbookMapping，其中包含一个对象列表 SpreadsheetMapping，并且每个对象都有另一个对象列表 CellMapping，因此是 Inception。当我尝试访问 SpreadsheetMapping 对象内的 CellMapping 列表的列表大小时，出现此错误:

>Exception occurred in target VM: illegal access to loading collection 
org.hibernate.LazyInitializationException: illegal access to loading collection
at org.hibernate.collection.AbstractPersistentCollection.initialize(AbstractPersistentCollection.java:341)
at org.hibernate.collection.AbstractPersistentCollection.read(AbstractPersistentCollection.java:86)
at org.hibernate.collection.AbstractPersistentCollection.readSize(AbstractPersistentCollection.java:109)
at org.hibernate.collection.PersistentBag.size(PersistentBag.java:225)
at csheets.io.SpreadSheetMapping.getSpreadSheet(SpreadSheetMapping.java:49)
at csheets.io.WorkbookMapping.getWorkbook(WorkbookMapping.java:49)
at csheets.io.XMLCodec.read(XMLCodec.java:69)
at csheets.CleanSheets.load(CleanSheets.java:178)
at csheets.ui.ctrl.OpenAction.actionPerformed(OpenAction.java:85)
at javax.swing.AbstractButton.fireActionPerformed(AbstractButton.java:2018)
at javax.swing.AbstractButton$Handler.actionPerformed(AbstractButton.java:2341)
at javax.swing.DefaultButtonModel.fireActionPerformed(DefaultButtonModel.java:402)
at javax.swing.DefaultButtonModel.setPressed(DefaultButtonModel.java:259)
at javax.swing.plaf.basic.BasicButtonListener.mouseReleased(BasicButtonListener.java:252)
at java.awt.AWTEventMulticaster.mouseReleased(AWTEventMulticaster.java:289)
at java.awt.Component.processMouseEvent(Component.java:6505)
at javax.swing.JComponent.processMouseEvent(JComponent.java:3321)
at java.awt.Component.processEvent(Component.java:6270)
at java.awt.Container.processEvent(Container.java:2229)
at java.awt.Component.dispatchEventImpl(Component.java:4861)
at java.awt.Container.dispatchEventImpl(Container.java:2287)
at java.awt.Component.dispatchEvent(Component.java:4687)
at java.awt.LightweightDispatcher.retargetMouseEvent(Container.java:4832)
at java.awt.LightweightDispatcher.processMouseEvent(Container.java:4492)
at java.awt.LightweightDispatcher.dispatchEvent(Container.java:4422)
at java.awt.Container.dispatchEventImpl(Container.java:2273)
at java.awt.Window.dispatchEventImpl(Window.java:2713)
at java.awt.Component.dispatchEvent(Component.java:4687)
at java.awt.EventQueue.dispatchEventImpl(EventQueue.java:707)
at java.awt.EventQueue.access$000(EventQueue.java:101)
at java.awt.EventQueue$3.run(EventQueue.java:666)
at java.awt.EventQueue$3.run(EventQueue.java:664)
at java.security.AccessController.doPrivileged(Native Method)
at java.security.ProtectionDomain$1.doIntersectionPrivilege(ProtectionDomain.java:76)
at java.security.ProtectionDomain$1.doIntersectionPrivilege(ProtectionDomain.java:87)
at java.awt.EventQueue$4.run(EventQueue.java:680)
at java.awt.EventQueue$4.run(EventQueue.java:678)
at java.security.AccessController.doPrivileged(Native Method)
at java.security.ProtectionDomain$1.doIntersectionPrivilege(ProtectionDomain.java:76)
at java.awt.EventQueue.dispatchEvent(EventQueue.java:677)
at java.awt.EventDispatchThread.pumpOneEventForFilters(EventDispatchThread.java:211)
at java.awt.EventDispatchThread.pumpEventsForFilter(EventDispatchThread.java:128)
at java.awt.EventDispatchThread.pumpEventsForHierarchy(EventDispatchThread.java:117)
at java.awt.EventDispatchThread.pumpEvents(EventDispatchThread.java:113)
at java.awt.EventDispatchThread.pumpEvents(EventDispatchThread.java:105)
at java.awt.EventDispatchThread.run(EventDispatchThread.java:90)

这是我的 WorkbookMapping 方法:

public Workbook getWorkbook() throws FormulaCompilationException{
    Workbook workbook = new Workbook();
    for(int i=0;i<this.list.size();i++){
        workbook.addSpreadsheet();
    }
    for(int i=0;i<this.list.size();i++){
        System.out.println("Spreadsheet size: "+this.list.size());
        this.list.get(i).getSpreadSheet();
    }

    //        Cell c = wkm.list.get(i).list.get(j).getCell(wkm.list.get(i).list.get(j));
    //        workbook.getSpreadsheet(i).getCell(c.getAddress()).setContent(c.getContent());       
    return workbook;
}

这是我在 SpreadSheetsMapping 中的方法:

public Spreadsheet getSpreadSheet(){
    System.out.println("Size: "+this.list.size());

    Spreadsheet ss=null; //= (Spreadsheet) ssm;
    return ss;
}

我就是不明白问题出在哪里。任何想法？ :/

Answer 1

您正在尝试在 session 之外使用惰性集合。要么让它变得非惰性，要么在原始 session 中加载集合，或者重新附加对象并在需要时加载它，或者在 View 过滤器中使用类似打开 session 的东西，或者......这最有意义取决于您的具体需求、应用程序等。