java - 将文本文件附加到文本区域

Question

我正在阅读文本文件(始终只有一行)。将其附加到 MoviesTextArea 中。

我已经尝试过移动语句变量。

public static void viewMovies() throws Exception {

    File file = new File("MovieStorage.txt");

    FileReader fileReader = new FileReader(file);

    BufferedReader reader = new BufferedReader(fileReader);



    String statement = "";

    while ((statement = reader.readLine()) != null) {

        System.out.println(statement);

        MoviesTextArea.append(statement);

    }

    reader.close();

}

堆栈跟踪:

at MovieShower.viewMovies(MovieShower.java:34)
    at Window1$3.actionPerformed(Window1.java:74)
    at javax.swing.AbstractButton.fireActionPerformed(AbstractButton.java:2022)
    at javax.swing.AbstractButton$Handler.actionPerformed(AbstractButton.java:2348)
    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.Component.processMouseEvent(Component.java:6533)
    at javax.swing.JComponent.processMouseEvent(JComponent.java:3324)
    at java.awt.Component.processEvent(Component.java:6298)
    at java.awt.Container.processEvent(Container.java:2236)
    at java.awt.Component.dispatchEventImpl(Component.java:4889)
    at java.awt.Container.dispatchEventImpl(Container.java:2294)
    at java.awt.Component.dispatchEvent(Component.java:4711)
    at java.awt.LightweightDispatcher.retargetMouseEvent(Container.java:4888)
    at java.awt.LightweightDispatcher.processMouseEvent(Container.java:4525)
    at java.awt.LightweightDispatcher.dispatchEvent(Container.java:4466)
    at java.awt.Container.dispatchEventImpl(Container.java:2280)
    at java.awt.Window.dispatchEventImpl(Window.java:2746)
    at java.awt.Component.dispatchEvent(Component.java:4711)
    at java.awt.EventQueue.dispatchEventImpl(EventQueue.java:758)
    at java.awt.EventQueue.access$500(EventQueue.java:97)
    at java.awt.EventQueue$3.run(EventQueue.java:709)
    at java.awt.EventQueue$3.run(EventQueue.java:703)
    at java.security.AccessController.doPrivileged(Native Method)
    at java.security.ProtectionDomain$JavaSecurityAccessImpl.doIntersectionPrivilege(ProtectionDomain.java:80)
    at java.security.ProtectionDomain$JavaSecurityAccessImpl.doIntersectionPrivilege(ProtectionDomain.java:90)
    at java.awt.EventQueue$4.run(EventQueue.java:731)
    at java.awt.EventQueue$4.run(EventQueue.java:729)
    at java.security.AccessController.doPrivileged(Native Method)
    at java.security.ProtectionDomain$JavaSecurityAccessImpl.doIntersectionPrivilege(ProtectionDomain.java:80)
    at java.awt.EventQueue.dispatchEvent(EventQueue.java:728)
    at java.awt.EventDispatchThread.pumpOneEventForFilters(EventDispatchThread.java:201)
    at java.awt.EventDispatchThread.pumpEventsForFilter(EventDispatchThread.java:116)
    at java.awt.EventDispatchThread.pumpEventsForHierarchy(EventDispatchThread.java:105)
    at java.awt.EventDispatchThread.pumpEvents(EventDispatchThread.java:101)
    at java.awt.EventDispatchThread.pumpEvents(EventDispatchThread.java:93)
    at java.awt.EventDispatchThread.run(EventDispatchThread.java:82)

根据要求添加了堆栈跟踪。我希望附加语句 String!

Answer 1

你的代码甚至不应该编译——MoviesTextArea没有在你发布的代码片段中定义——但正如@Luke所说，它几乎必须为空。

此外，MoviesTextArea 以大写字母开头，因此它应该是一个类(类的实例应始终以小写字母开头)。如果是这种情况，尽管该类不能为空，但这将使空指针异常不可能出现。

因此，我的猜测是，它是一个实例，而您没有遵循将实例设置为小写的惯例，这只会给任何试图提供帮助的人增加困惑。

如果您可以发布一些编译、运行并显示错误的代码，我们可以提供更多帮助。 (最小可验证可执行示例或类似示例)