Java FileReader找不到文件

Question

我决定开始一个新问题，以便可以严格关注FileReader错误。

此方法采用文件名和新文件的所需输出名。假设输入的文件名是“ 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，即使该文件确实存在并且目录结构和权限正确，我仍将其作为输出“
/home/User/hello.txt（无此类文件或目录）”获得。

我无法仅通过引用.class和.java文件的本地目录中的文件来使用该方法，因此我用谷歌搜索的方式来发现绝对指定不是一个坏选择。

任何输入都是有帮助的！

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.<init>(FileInputStream.java:137)
    at java.io.FileInputStream.<init>(FileInputStream.java:96)
    at java.io.FileReader.<init>(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)

Answer 1

打印出是什么current_directory，并确认它符合您的期望。

我还将打印出您传递给的完整文件路径FileReader。

大多数情况下，这种行为与我的期望不符，我发现我的假设是错误的。