Java AWT-EventQueue-0错误

有人能帮我调试一下吗

编辑1：错误不在下面的代码中 *以下代码中出现错误：*

54号线上有什么

 at Server.getPeerFiles(Server.java:54)

是空的，所以第54行

编辑：

可能为空的内容：

e, btnRefresh, PeerList, FileList, Services

54号线上的任何一个都是你的事业

---

（很抱歉，我不知道要将其添加到我的原始帖子中）

每次更改选择时都会调用ListSelectionListener。这可能意味着现在没有选择，

lspeerlist.getSelectedValue（）

返回

null

。然后调用

getPeerFiles（null）

，此方法似乎无法处理

null

参数

---

您可以更改

getPeerFiles

方法，也可以仅在所选值不为

null

时调用该方法。我正在编辑问题，我已经找到了错误的位置，因为在该位置，如果我用字符串替换变量，则不会发生错误重新格式化的代码；如果不正确，请还原。是的，这就是问题所在，在某个地方我调用ListSelectionListener清空列表并返回null，谢谢

SelectedPeer=(String)lstPeerList.getSelectedValue();
List <String> PeerFiles=Services.getPeerFiles(SelectedPeer);

SelectedPeer=(String)lstPeerList.getSelectedValue();
List <String> PeerFiles=Services.getPeerFiles("Noor");

Exception in thread "AWT-EventQueue-0" java.lang.NullPointerException
        at Server.getPeerFiles(Server.java:54)
        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 sun.rmi.server.UnicastServerRef.dispatch(UnicastServerRef.java:305)
        at sun.rmi.transport.Transport$1.run(Transport.java:159)
        at java.security.AccessController.doPrivileged(Native Method)
        at sun.rmi.transport.Transport.serviceCall(Transport.java:155)
        at sun.rmi.transport.tcp.TCPTransport.handleMessages(TCPTransport.java:535)
        at sun.rmi.transport.tcp.TCPTransport$ConnectionHandler.run0(TCPTransport.java:790)
        at sun.rmi.transport.tcp.TCPTransport$ConnectionHandler.run(TCPTransport.java:649)
        at java.util.concurrent.ThreadPoolExecutor$Worker.runTask(ThreadPoolExecutor.java:886)
        at java.util.concurrent.ThreadPoolExecutor$Worker.run(ThreadPoolExecutor.java:908)
        at java.lang.Thread.run(Thread.java:637)
        at sun.rmi.transport.StreamRemoteCall.exceptionReceivedFromServer(StreamRemoteCall.java:255)
        at sun.rmi.transport.StreamRemoteCall.executeCall(StreamRemoteCall.java:233)
        at sun.rmi.server.UnicastRef.invoke(UnicastRef.java:142)
        at java.rmi.server.RemoteObjectInvocationHandler.invokeRemoteMethod(RemoteObjectInvocationHandler.java:178)
        at java.rmi.server.RemoteObjectInvocationHandler.invoke(RemoteObjectInvocationHandler.java:132)
        at $Proxy0.getPeerFiles(Unknown Source)
        at MainForm$1.valueChanged(MainForm.java:55)
        at javax.swing.JList.fireSelectionValueChanged(JList.java:1765)
        at javax.swing.JList$ListSelectionHandler.valueChanged(JList.java:1779)
        at javax.swing.DefaultListSelectionModel.fireValueChanged(DefaultListSelectionModel.java:167)
        at javax.swing.DefaultListSelectionModel.fireValueChanged(DefaultListSelectionModel.java:147)
        at javax.swing.DefaultListSelectionModel.fireValueChanged(DefaultListSelectionModel.java:194)
        at javax.swing.DefaultListSelectionModel.removeIndexInterval(DefaultListSelectionModel.java:660)
        at javax.swing.plaf.basic.BasicListUI$Handler.intervalRemoved(BasicListUI.java:2589)
        at javax.swing.AbstractListModel.fireIntervalRemoved(AbstractListModel.java:161)
        at javax.swing.DefaultListModel.removeAllElements(DefaultListModel.java:385)
        at MainForm.actionPerformed(MainForm.java:223)
        at javax.swing.AbstractButton.fireActionPerformed(AbstractButton.java:1995)
        at javax.swing.AbstractButton$Handler.actionPerformed(AbstractButton.java:2318)
        at javax.swing.DefaultButtonModel.fireActionPerformed(DefaultButtonModel.java:387)
        at javax.swing.DefaultButtonModel.setPressed(DefaultButtonModel.java:242)
        at javax.swing.plaf.basic.BasicButtonListener.mouseReleased(BasicButtonListener.java:236)
        at java.awt.Component.processMouseEvent(Component.java:6267)
        at javax.swing.JComponent.processMouseEvent(JComponent.java:3267)
        at java.awt.Component.processEvent(Component.java:6032)
        at java.awt.Container.processEvent(Container.java:2041)
        at java.awt.Component.dispatchEventImpl(Component.java:4630)
        at java.awt.Container.dispatchEventImpl(Container.java:2099)
        at java.awt.Component.dispatchEvent(Component.java:4460)
        at java.awt.LightweightDispatcher.retargetMouseEvent(Container.java:4577)
        at java.awt.LightweightDispatcher.processMouseEvent(Container.java:4238)
        at java.awt.LightweightDispatcher.dispatchEvent(Container.java:4168)
        at java.awt.Container.dispatchEventImpl(Container.java:2085)
        at java.awt.Window.dispatchEventImpl(Window.java:2478)
        at java.awt.Component.dispatchEvent(Component.java:4460)
        at java.awt.EventQueue.dispatchEvent(EventQueue.java:599)
        at java.awt.EventDispatchThread.pumpOneEventForFilters(EventDispatchThread.java:269)
        at java.awt.EventDispatchThread.pumpEventsForFilter(EventDispatchThread.java:184)
        at java.awt.EventDispatchThread.pumpEventsForHierarchy(EventDispatchThread.java:174)
        at java.awt.EventDispatchThread.pumpEvents(EventDispatchThread.java:169)
        at java.awt.EventDispatchThread.pumpEvents(EventDispatchThread.java:161)
        at java.awt.EventDispatchThread.run(EventDispatchThread.java:122)

 at Server.getPeerFiles(Server.java:54)

e, btnRefresh, PeerList, FileList, Services