打开一个jsp页面出现如下错误Could not open the editor: An unexpected exception was thrown.

Question

j之前可以打开jsp界面的  把jsp放到WEB—INF下 出项 错误
Could not open the editor: An unexpected exception was thrown.
ava.lang.NullPointerException
at com.genuitec.eclipse.webdesigner3.src.SourceEditSystem.getSourceDocument(SourceEditSystem.java:259)
at com.genuitec.eclipse.webdesigner3.design.DesignEditSystem.synchronize(DesignEditSystem.java:186)
at com.genuitec.eclipse.webdesigner3.AbstractEditSystem.setSynchronized(AbstractEditSystem.java:24)
at com.genuitec.eclipse.webdesigner3.WebDesigner3.setSynchronized(WebDesigner3.java:114)
at com.genuitec.eclipse.webdesigner3.editors.WebDesignerMultiPageEditor.checkSynchronization(WebDesignerMultiPageEditor.java:1077)
at com.genuitec.eclipse.webdesigner3.editors.WebDesignerMultiPageEditor.access$7(WebDesignerMultiPageEditor.java:1073)
at com.genuitec.eclipse.webdesigner3.editors.WebDesignerMultiPageEditor$11.run(WebDesignerMultiPageEditor.java:1044)
at org.eclipse.swt.custom.BusyIndicator.showWhile(BusyIndicator.java:70)
at com.genuitec.eclipse.webdesigner3.editors.WebDesignerMultiPageEditor.designPageChange(WebDesignerMultiPageEditor.java:1042)
at com.genuitec.eclipse.webdesigner3.editors.WebDesignerMultiPageEditor.pageChange(WebDesignerMultiPageEditor.java:1013)
at org.eclipse.ui.part.MultiPageEditorPart.setActivePage(MultiPageEditorPart.java:1067)
at org.eclipse.ui.part.MultiPageEditorPart.createPartControl(MultiPageEditorPart.java:352)
at org.eclipse.ui.internal.EditorReference.createPartHelper(EditorReference.java:670)
at org.eclipse.ui.internal.EditorReference.createPart(EditorReference.java:465)
at org.eclipse.ui.internal.WorkbenchPartReference.getPart(WorkbenchPartReference.java:595)
at org.eclipse.ui.internal.EditorReference.getEditor(EditorReference.java:289)
at org.eclipse.ui.internal.WorkbenchPage.busyOpenEditorBatched(WorkbenchPage.java:2863)
at org.eclipse.ui.internal.WorkbenchPage.busyOpenEditor(WorkbenchPage.java:2768)
at org.eclipse.ui.internal.WorkbenchPage.access$11(WorkbenchPage.java:2760)
at org.eclipse.ui.internal.WorkbenchPage$10.run(WorkbenchPage.java:2711)
at org.eclipse.swt.custom.BusyIndicator.showWhile(BusyIndicator.java:70)
at org.eclipse.ui.internal.WorkbenchPage.openEditor(WorkbenchPage.java:2707)
at org.eclipse.ui.internal.WorkbenchPage.openEditor(WorkbenchPage.java:2691)
at org.eclipse.ui.actions.OpenWithMenu.openEditor(OpenWithMenu.java:331)
at org.eclipse.ui.actions.OpenWithMenu$2.handleEvent(OpenWithMenu.java:179)
at org.eclipse.swt.widgets.EventTable.sendEvent(EventTable.java:84)
at org.eclipse.swt.widgets.Widget.sendEvent(Widget.java:1053)
at org.eclipse.swt.widgets.Display.runDeferredEvents(Display.java:4066)
at org.eclipse.swt.widgets.Display.readAndDispatch(Display.java:3657)
at org.eclipse.ui.internal.Workbench.runEventLoop(Workbench.java:2640)
at org.eclipse.ui.internal.Workbench.runUI(Workbench.java:2604)
at org.eclipse.ui.internal.Workbench.access$4(Workbench.java:2438)
at org.eclipse.ui.internal.Workbench$7.run(Workbench.java:671)
at org.eclipse.core.databinding.observable.Realm.runWithDefault(Realm.java:332)
at org.eclipse.ui.internal.Workbench.createAndRunWorkbench(Workbench.java:664)
at org.eclipse.ui.PlatformUI.createAndRunWorkbench(PlatformUI.java:149)
at org.eclipse.ui.internal.ide.application.IDEApplication.start(IDEApplication.java:115)
at org.eclipse.equinox.internal.app.EclipseAppHandle.run(EclipseAppHandle.java:196)
at org.eclipse.core.runtime.internal.adaptor.EclipseAppLauncher.runApplication(EclipseAppLauncher.java:110)
at org.eclipse.core.runtime.internal.adaptor.EclipseAppLauncher.start(EclipseAppLauncher.java:79)
at org.eclipse.core.runtime.adaptor.EclipseStarter.run(EclipseStarter.java:369)
at org.eclipse.core.runtime.adaptor.EclipseStarter.run(EclipseStarter.java:179)
at sun.reflect.NativeMethodAccessorImpl.invoke0(Native Method)
at sun.reflect.NativeMethodAccessorImpl.invoke(NativeMethodAccessorImpl.java:39)
at sun.reflect.DelegatingMethodAccessorImpl.invoke(DelegatingMethodAccessorImpl.java:25)
at java.lang.reflect.Method.invoke(Method.java:597)
at org.eclipse.equinox.launcher.Main.invokeFramework(Main.java:619)
at org.eclipse.equinox.launcher.Main.basicRun(Main.java:574)
at org.eclipse.equinox.launcher.Main.run(Main.java:1407)

Answer 1

找到struts-config.xml  同级目录，看是否有.struts.mex这个文件， 然后删除，关闭eclipse,重新打开， 选择struts-config.xml 右键 选择 exlipse editor, jsp页面 也右键选择 editor ，然后重新运行 

Answer 2

看下是否是别的jsp引用你这个jsp文件，而你路径没有修改。

Answer 3

我也出现这个问题 本来想直接重装的 结果 myeclipse重启下 就可以了