我知道这个问题很常见，所以我一直在网上疯狂地寻找解决方案，但无济于事。我只是想从程序 JAR 中加载一个包含一些文本的文件。这是我试图阅读的内容：
String text = "";
int read, N = 1024 * 1024;
char[] buffer = new char[N];
try {
InputStream is = this.getClass().getClassLoader().getResourceAsStream("/help.txt");
BufferedReader br = new BufferedReader(new InputStreamReader(is));
while(true) {
read = br.read(buffer, 0, N);
text += new String(buffer, 0, read);
if(read < N) {
break;
}
}
} catch(Exception ex) {
ex.printStackTrace();
}
我不太了解 java/eclipse 构建路径的东西。但我已将 help.txt 放在项目文件夹的根目录中。我目前在执行上面的代码时收到此错误。
java.lang.NullPointerException
at java.io.Reader.<init>(Reader.java:78)
at java.io.InputStreamReader.<init>(InputStreamReader.java:72)
at ajax.Gui.printHelp(Gui.java:330)
at ajax.Gui.onCommand(Gui.java:151)
at ajax.Gui$1.actionPerformed(Gui.java:130)
at javax.swing.JTextField.fireActionPerformed(JTextField.java:508)
at javax.swing.JTextField.postActionEvent(JTextField.java:721)
at javax.swing.JTextField$NotifyAction.actionPerformed(JTextField.java:836)
at javax.swing.SwingUtilities.notifyAction(SwingUtilities.java:1661)
at javax.swing.JComponent.processKeyBinding(JComponent.java:2870)
at javax.swing.JComponent.processKeyBindings(JComponent.java:2917)
at javax.swing.JComponent.processKeyEvent(JComponent.java:2833)
at java.awt.Component.processEvent(Component.java:6282)
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.KeyboardFocusManager.redispatchEvent(KeyboardFocusManager.java:1895)
at java.awt.DefaultKeyboardFocusManager.dispatchKeyEvent(DefaultKeyboardFocusManager.java:762)
at java.awt.DefaultKeyboardFocusManager.preDispatchKeyEvent(DefaultKeyboardFocusManager.java:1027)
at java.awt.DefaultKeyboardFocusManager.typeAheadAssertions(DefaultKeyboardFocusManager.java:899)
at java.awt.DefaultKeyboardFocusManager.dispatchEvent(DefaultKeyboardFocusManager.java:727)
at java.awt.Component.dispatchEventImpl(Component.java:4731)
at java.awt.Container.dispatchEventImpl(Container.java:2287)
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)
做什么？一些额外信息：操作系统 = Linux Mint 14 KDE，JDK = JavaSE1.7，IDE = Eclipse