myEclipse 打不开struts-config.xml 报Could not open the editor: An unexpected exception was thrown 错误(转载)

出现错误如下：

提示错误信息：Could not open the editor: An unexpected exception was thrown. 
java.lang.NullPointerException 
at com.genuitec.eclipse.struts.editor.modeler.model.StrutsConfigDiagram.processAction(StrutsConfigDiagram.java:574) 
at com.genuitec.eclipse.struts.editor.modeler.model.StrutsConfigDiagram.synchronizeDiagram(StrutsConfigDiagram.java:479) 
at com.genuitec.eclipse.struts.editor.modeler.model.StrutsConfigDiagram.differedSynchronize(StrutsConfigDiagram.java:120) 
at com.genuitec.eclipse.struts.editor.multipage.StrutsConfigEditor.createPages(StrutsConfigEditor.java:296) 
at org.eclipse.ui.part.MultiPageEditorPart.createPartControl(MultiPageEditorPart.java:357) 
at org.eclipse.ui.internal.EditorReference.createPartHelper(EditorReference.java:662) 
at org.eclipse.ui.internal.EditorReference.createPart(EditorReference.java:462)
at org.eclipse.ui.internal.WorkbenchPartReference.getPart(WorkbenchPartReference.java:595) 
at org.eclipse.ui.internal.PartPane.setVisible(PartPane.java:313) 
at org.eclipse.ui.internal.presentations.PresentablePart.setVisible(PresentablePart.java:180) 
at org.eclipse.ui.internal.presentations.util.PresentablePartFolder.select(PresentablePartFolder.java:270) 
at org.eclipse.ui.internal.presentations.util.LeftToRightTabOrder.select(LeftToRightTabOrder.java:65) 
at org.eclipse.ui.internal.presentations.util.TabbedStackPresentation.selectPart(TabbedStackPresentation.java:473) 
at org.eclipse.ui.internal.PartStack.refreshPresentationSelection(PartStack.java:1256) 
at org.eclipse.ui.internal.PartStack.setSelection(PartStack.java:1209) 
at org.eclipse.ui.internal.PartStack.showPart(PartStack.java:1608) 
at org.eclipse.ui.internal.PartStack.add(PartStack.java:499) 
at org.eclipse.ui.internal.EditorStack.add(EditorStack.java:103) 
at org.eclipse.ui.internal.PartStack.add(PartStack.java:485) 
at org.eclipse.ui.internal.EditorStack.add(EditorStack.java:112)......

解决办法：

struts-config.xml目录上面点击右键--> open with -->myeclipse xml editor