Java FileReader无法查找文件
我决定开始一个新问题，因此它可以严格关注FileReader错误。
这是一种方法，它接收文件名和新文件的所需输出名称。 假设输入的文件名为“hello.txt”…该方法使其类似于“/home/User/hello.txt”，它作为参数进入FileReader。 问题是我把它作为输出“/home/User/hello.txt（没有这样的文件或目录）”，即使该文件确实存在且目录结构和权限是正确的。
我只能在.class和.java文件的本地目录中引用该文件来使用该方法，所以我用google搜索绝对指定并不是一个糟糕的选项。
任何输入都有帮助！
public void fileGenerator(String in, String out) { try { String current_directory = System.getProperty("user.dir"); Scanner input = new Scanner(new FileReader(current_directory+"/"+in)); PrintWriter output = new PrintWriter(current_directory+"/"+out); while(input.hasNext()) { String line = input.nextLine(); output.println(line); output.close(); } } catch (Exception e) { System.out.println(e.getMessage()); } } 这是请求的堆栈跟踪：
java.io.FileNotFoundException: /home/User/hello.txt (No such file or directory) at java.io.FileInputStream.open(Native Method) at java.io.FileInputStream.(FileInputStream.java:137) at java.io.FileInputStream.(FileInputStream.java:96) at java.io.FileReader.(FileReader.java:58) at TEST.fileGenerator(TEST.java:131) at TEST.generateCSV_TWO(TEST.java:122) at TEST$4.actionPerformed(TEST.java:102) at javax.swing.AbstractButton.fireActionPerformed(AbstractButton.java:2012) at javax.swing.AbstractButton$Handler.actionPerformed(AbstractButton.java:2335) at javax.swing.DefaultButtonModel.fireActionPerformed(DefaultButtonModel.java:404) at javax.swing.DefaultButtonModel.setPressed(DefaultButtonModel.java:259) at javax.swing.plaf.basic.BasicButtonListener.mouseReleased(BasicButtonListener.java:253) at java.awt.Component.processMouseEvent(Component.java:6203) at javax.swing.JComponent.processMouseEvent(JComponent.java:3267) at java.awt.Component.processEvent(Component.java:5968) at java.awt.Container.processEvent(Container.java:2105) at java.awt.Component.dispatchEventImpl(Component.java:4564) at java.awt.Container.dispatchEventImpl(Container.java:2163) at java.awt.Component.dispatchEvent(Component.java:4390) at java.awt.LightweightDispatcher.retargetMouseEvent(Container.java:4461) at java.awt.LightweightDispatcher.processMouseEvent(Container.java:4125) at java.awt.LightweightDispatcher.dispatchEvent(Container.java:4055) at java.awt.Container.dispatchEventImpl(Container.java:2149) at java.awt.Window.dispatchEventImpl(Window.java:2478) at java.awt.Component.dispatchEvent(Component.java:4390) at java.awt.EventQueue.dispatchEventImpl(EventQueue.java:649) at java.awt.EventQueue.access$000(EventQueue.java:96) at java.awt.EventQueue$1.run(EventQueue.java:608) at java.awt.EventQueue$1.run(EventQueue.java:606) at java.security.AccessController.doPrivileged(Native Method) at java.security.AccessControlContext$1.doIntersectionPrivilege(AccessControlContext.java:105) at java.security.AccessControlContext$1.doIntersectionPrivilege(AccessControlContext.java:116) at java.awt.EventQueue$2.run(EventQueue.java:622) at java.awt.EventQueue$2.run(EventQueue.java:620) at java.security.AccessController.doPrivileged(Native Method) at java.security.AccessControlContext$1.doIntersectionPrivilege(AccessControlContext.java:105) at java.awt.EventQueue.dispatchEvent(EventQueue.java:619) at java.awt.EventDispatchThread.pumpOneEventForFilters(EventDispatchThread.java:275) at java.awt.EventDispatchThread.pumpEventsForFilter(EventDispatchThread.java:200) at java.awt.EventDispatchThread.pumpEventsForHierarchy(EventDispatchThread.java:190) at java.awt.EventDispatchThread.pumpEvents(EventDispatchThread.java:185) at java.awt.EventDispatchThread.pumpEvents(EventDispatchThread.java:177) at java.awt.EventDispatchThread.run(EventDispatchThread.java:138)
打印出current_directory是什么，并确认它符合您的期望。
我还打印出您传递给FileReader的完整文件路径。
大多数时候这种行为与我的期望不符，我发现我的假设是错误的。
没有这样的文件或目录通常意味着文件不存在。 请编辑代码并使用IDE或添加print语句对其进行调试。 此外，current_directory可以重命名为currentDirectory，以与Java命名约定保持一致。 尝试运行以下代码。
public static void fileGenerator(String in, String out) { try { String currentDirectory = System.getProperty("user.dir"); System.out.println(currentDirectory); String inputFileName = currentDirectory+"/"+in; File inputFile = new File(inputFileName); System.out.println(inputFile.getAbsolutePath()); FileReader inputFileReader = new FileReader(inputFile); Scanner input = new Scanner(inputFileReader); PrintWriter output = new PrintWriter(currentDirectory+"/"+out); while(input.hasNext()) { String line = input.nextLine(); output.println(line); output.close(); } } catch (Exception e) { e.printStackTrace(); } }