私は Java と MongoDB の世界では初めてです。Mngodb にデータを正常に挿入できますが、ボタンの下にこの単純なコードを記述すると、次のエラーが発生します。
Exception in thread "AWT-EventQueue-0" java.lang.NullPointerException
これは私のコードブロックです:
private void jButton1ActionPerformed(java.awt.event.ActionEvent evt) {
Morphia morphia=new Morphia();
Datastore ds2 = morphia.createDatastore(mongo,"rcfdb");
Query q=ds2.createQuery(District.class).field("Name").equal(jTextField1.getText());
}
この行を削除すると、エラーなしで機能します。
Datastore ds2 = morphia.createDatastore(mongo,"rcfdb");
この問題を解決するのを手伝ってもらえますか? このクエリの結果を別のラベルで表示する方法を教えてください。
本当にありがとう
アップデート
Jul 09, 2013 5:16:43 PM com.google.code.morphia.logging.MorphiaLoggerFactory chooseLoggerFactory
INFO: LoggerImplFactory set to com.google.code.morphia.logging.jdk.JDKLoggerFactory
Exception in thread "AWT-EventQueue-0" java.lang.NullPointerException
at com.google.code.morphia.DatastoreImpl.<init>(DatastoreImpl.java:79)
at com.google.code.morphia.DatastoreImpl.<init>(DatastoreImpl.java:90)
at com.google.code.morphia.Morphia.createDatastore(Morphia.java:170)
at com.google.code.morphia.Morphia.createDatastore(Morphia.java:177)
at rcf.mongodb.TestForm.jButton1ActionPerformed(TestForm.java:94)
at rcf.mongodb.TestForm.access$100(TestForm.java:17)
at rcf.mongodb.TestForm$2.actionPerformed(TestForm.java:53)
at javax.swing.AbstractButton.fireActionPerformed(AbstractButton.java:2018)
at javax.swing.AbstractButton$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:2719)
at java.awt.Component.dispatchEvent(Component.java:4687)
at java.awt.EventQueue.dispatchEventImpl(EventQueue.java:729)
at java.awt.EventQueue.access$200(EventQueue.java:103)
at java.awt.EventQueue$3.run(EventQueue.java:688)
at java.awt.EventQueue$3.run(EventQueue.java:686)
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:702)
at java.awt.EventQueue$4.run(EventQueue.java:700)
at java.security.AccessController.doPrivileged(Native Method)
at java.security.ProtectionDomain$1.doIntersectionPrivilege(ProtectionDomain.java:76)
at java.awt.EventQueue.dispatchEvent(EventQueue.java:699)
at java.awt.EventDispatchThread.pumpOneEventForFilters(EventDispatchThread.java:242)
at java.awt.EventDispatchThread.pumpEventsForFilter(EventDispatchThread.java:161)
at java.awt.EventDispatchThread.pumpEventsForHierarchy(EventDispatchThread.java:150)
at java.awt.EventDispatchThread.pumpEvents(EventDispatchThread.java:146)
at java.awt.EventDispatchThread.pumpEvents(EventDispatchThread.java:138)
at java.awt.EventDispatchThread.run(EventDispatchThread.java:91)
BUILD SUCCESSFUL (total time: 11 seconds)