使用FileOutputStream时拒绝访问

Question

我有一个问题让这个工作.它包含一个由多条信息组成的字符串.但是,当我尝试将String写入文件以便跟踪程序随时间的变化时,我收到一个拒绝访问错误:

 void writeToFile(String input) throws Exception{
            File file = new File("C:\\WeatherExports\\export.txt");
            if(!file.exists()){
                    file.createNewFile();
            }
            BufferedWriter inFile = new BufferedWriter(new FileWriter(file,true));
            try{
                    inFile.append(input);
                    inFile.newLine();
            } catch(Exception e){
                    e.printStackTrace();
            }
            inFile.close();
    }

STACKTRACE YEILDS:

java.io.FileNotFoundException: C:\WeatherExports\export.txt (Access is denied)

完整Stacktrace:

java.io.FileNotFoundException: C:\WeatherExports\export.txt (Access is denied)
at java.io.FileOutputStream.openAppend(Native Method)
at java.io.FileOutputStream.<init>(Unknown Source)
at java.io.FileWriter.<init>(Unknown Source)
at org.weatheralert.InfoManipMethods.writeToFile(InfoManipMethods.java:58)
at org.weatheralert.Form.actionPerformed(Form.java:108)
at javax.swing.JTextField.fireActionPerformed(Unknown Source)
at javax.swing.JTextField.postActionEvent(Unknown Source)
at javax.swing.JTextField$NotifyAction.actionPerformed(Unknown Source)
at javax.swing.SwingUtilities.notifyAction(Unknown Source)
at javax.swing.JComponent.processKeyBinding(Unknown Source)
at javax.swing.JComponent.processKeyBindings(Unknown Source)
at javax.swing.JComponent.processKeyEvent(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.KeyboardFocusManager.redispatchEvent(Unknown Source)
at java.awt.DefaultKeyboardFocusManager.dispatchKeyEvent(Unknown Source)
at java.awt.DefaultKeyboardFocusManager.preDispatchKeyEvent(Unknown Source)
at java.awt.DefaultKeyboardFocusManager.typeAheadAssertions(Unknown Source)
at java.awt.DefaultKeyboardFocusManager.dispatchEvent(Unknown Source)
at java.awt.Component.dispatchEventImpl(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$1.run(Unknown Source)
at java.awt.EventQueue$1.run(Unknown Source)
at java.security.AccessController.doPrivileged(Native Method)
at java.security.AccessControlContext$1.doIntersectionPrivilege(Unknown Source)
at java.security.AccessControlContext$1.doIntersectionPrivilege(Unknown Source)
at java.awt.EventQueue$2.run(Unknown Source)
at java.awt.EventQueue$2.run(Unknown Source)
at java.security.AccessController.doPrivileged(Native Method)
at java.security.AccessControlContext$1.doIntersectionPrivilege(Unknown Source)
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)

第58行:

BufferedWriter inFile = new BufferedWriter(new FileWriter(file,true));

Answer 1

您必须先创建文件夹.但你不能调用file.mkdirs() - 你需要调用file.getParentFile().mkdirs() - 否则,你将创建一个文件名的文件夹(这将阻止你创建一个文件同名).

我还要提到你应该检查mkdirs()的结果代码,以防它失败.

虽然你没有要求的话,我还是会提到,你不需要调用createNewFile()(你的FileWriter将创建它).

并且,只为彻底,一定要把你的file.close()在finally块,并把你的异常(不只是打印) - 在这里你去:

 void writeToFile(String input) throws IOException{
            File file = new File("C:\\WeatherExports\\export.txt");
            if (!file.getParentFile().mkdirs())
                    throw new IOException("Unable to create " + file.getParentFile());
            BufferedWriter out = new BufferedWriter(new FileWriter(file,true));
            try{
                    out.append(input);
                    out.newLine();
            } finally {
                    out.close();
            } 
    }

Answer 2

还有另一种可能性(仅适用于事后可能正在阅读此内容的任何人).我有同样的问题,但所有的父文件夹都存在.问题是,有一个文件夹与我试图创建的文件同名.