java - 导出后 Java Eclipse 项目出现问题

Question

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9年前关闭。




我已经为学校做这个 Java 项目好几个星期了，几天前我完成了它。它是一个数据库管理员软件，旨在运行 Access 数据库，在本例中是我学校的数据库。在 Eclipse IDE 中一切正常，显示 0 个错误，0 个警告。然后，当我导出导出的文件时，我也没有收到任何错误，但是当我打开项目时，菜单的 6 个按钮中只有 2 个有效。菜单有 6 个按钮。 5个与Access连接并显示不同的数据，其中只有一个起作用，另一个起作用的选项卡是退出按钮。因此，我在 cmd 中运行导出的程序以获得更精确的错误，然后弹出此日志。

C:\Users\IVAN>java -jar prueba.jar
consulta busar registro: SELECT * FROM StudentsAbsences ORDER BY Id;
Exception in thread "AWT-EventQueue-0" java.lang.NullPointerException
        at javax.swing.ImageIcon.<init>(Unknown Source)
        at ModificarAlumno.getCancelar_btn(ModificarAlumno.java:199)
        at ModificarAlumno.getJContentPane(ModificarAlumno.java:385)
        at ModificarAlumno.initialize(ModificarAlumno.java:310)
        at ModificarAlumno.<init>(ModificarAlumno.java:298)
        at Menu$4.actionPerformed(Menu.java:127)
        at javax.swing.AbstractButton.fireActionPerformed(Unknown Source)
        at javax.swing.AbstractButton$Handler.actionPerformed(Unknown Source)
        at javax.swing.DefaultButtonModel.fireActionPerformed(Unknown Source)
        at javax.swing.DefaultButtonModel.setPressed(Unknown Source)
        at javax.swing.plaf.basic.BasicButtonListener.mouseReleased(Unknown Sour
ce)
        at java.awt.Component.processMouseEvent(Unknown Source)
        at javax.swing.JComponent.processMouseEvent(Unknown Source)
        at java.awt.Component.processEvent(Unknown Source)
        at java.awt.Container.processEvent(Unknown Source)
        at java.awt.Component.dispatchEventImpl(Unknown Source)
        at java.awt.Container.dispatchEventImpl(Unknown Source)
        at java.awt.Component.dispatchEvent(Unknown Source)
        at java.awt.LightweightDispatcher.retargetMouseEvent(Unknown Source)
        at java.awt.LightweightDispatcher.processMouseEvent(Unknown Source)
        at java.awt.LightweightDispatcher.dispatchEvent(Unknown Source)
        at java.awt.Container.dispatchEventImpl(Unknown Source)
        at java.awt.Window.dispatchEventImpl(Unknown Source)
        at java.awt.Component.dispatchEvent(Unknown Source)
        at java.awt.EventQueue.dispatchEventImpl(Unknown Source)
        at java.awt.EventQueue.access$000(Unknown Source)
        at java.awt.EventQueue$3.run(Unknown Source)
        at java.awt.EventQueue$3.run(Unknown Source)
        at java.security.AccessController.doPrivileged(Native Method)
        at java.security.ProtectionDomain$1.doIntersectionPrivilege(Unknown Sour
ce)
        at java.security.ProtectionDomain$1.doIntersectionPrivilege(Unknown Sour
ce)
        at java.awt.EventQueue$4.run(Unknown Source)
        at java.awt.EventQueue$4.run(Unknown Source)
        at java.security.AccessController.doPrivileged(Native Method)
        at java.security.ProtectionDomain$1.doIntersectionPrivilege(Unknown Sour
ce)
        at java.awt.EventQueue.dispatchEvent(Unknown Source)
        at java.awt.EventDispatchThread.pumpOneEventForFilters(Unknown Source)
        at java.awt.EventDispatchThread.pumpEventsForFilter(Unknown Source)
        at java.awt.EventDispatchThread.pumpEventsForHierarchy(Unknown Source)
        at java.awt.EventDispatchThread.pumpEvents(Unknown Source)
        at java.awt.EventDispatchThread.pumpEvents(Unknown Source)
        at java.awt.EventDispatchThread.run(Unknown Source)

我是 stackoverflow 的新手，真的从未使用过这个问答网页，所以我不确定我是否必须发布其他内容。我必须在星期二交上工作项目，所以我很着急。任何帮助表示赞赏，如果您需要有关该项目的更多信息，请告诉我，我会尽快发布。非常感谢你。

Answer 1

看起来下面的代码正在抛出 NullPointerException。

    at javax.swing.ImageIcon.<init>(Unknown Source)
    at ModificarAlumno.getCancelar_btn(ModificarAlumno.java:199)

这意味着在 ModificarAlumno.getCancelar_btn() 中，您正在构建一个新的 ImageIcon，并且在其构造函数中抛出异常。可能是导出后图像没有正确加载吗？如果这没有帮助，请发布其他代码。