java - 在文件名中使用 .txt 时抛出异常

Question

我正在尝试运行以下代码，其中我必须将文件另存为 .txt...但是每当我单击“保存”按钮时...它会引发异常..

我还想知道如何将textarea的内容逐行保存在txt文件中(包括\n)。

这是代码

try
{
    int val = jfc.showSaveDialog(jf);
    int x =0;
    String line;
    if(val == JFileChooser.APPROVE_OPTION)
    {
        File fs=jfc.getSelectedFile();
        if(!fs.exists())
        {
            fs.createNewFile();
            FileWriter fw=new FileWriter(fs.getAbsolutePath()+".txt");
            BufferedWriter bf=new BufferedWriter(fw);
            BufferedReader br = new BufferedReader(new StringReader(ja.getText()));
            while((line= br.readLine())!=null)
            {
                x++;
                if(line.charAt(x)=='\n')
                    fw.write('\n');
                else
                    fw.write(line+"\n");
            }
            fw.close();
        }
        else
        {

        }
    }
}
catch(Exception e2)
{
    e2.printStackTrace();
    JOptionPane.showMessageDialog(null,"Cannot save file");
}

java.lang.StringIndexOutOfBoundsException: String index out of range: 3
    at java.lang.String.charAt(String.java:658)
    at notepad$1.actionPerformed(notepad.java:100)
    at javax.swing.AbstractButton.fireActionPerformed(AbstractButton.java:2018)
    at javax.swing.AbstractButton$Handler.actionPerformed(AbstractButton.java:2341)
    at javax.swing.DefaultButtonModel.fireActionPerformed(DefaultButtonModel.java:402)
    at javax.swing.DefaultButtonModel.setPressed(DefaultButtonModel.java:259)
    at javax.swing.AbstractButton.doClick(AbstractButton.java:376)
    at javax.swing.plaf.basic.BasicMenuItemUI.doClick(BasicMenuItemUI.java:833)
    at javax.swing.plaf.basic.BasicMenuItemUI$Handler.mouseReleased(BasicMenuItemUI.java:877)
    at java.awt.Component.processMouseEvent(Component.java:6505)
    at javax.swing.JComponent.processMouseEvent(JComponent.java:3320)
    at java.awt.Component.processEvent(Component.java:6270)
    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.LightweightDispatcher.retargetMouseEvent(Container.java:4832)
    at java.awt.LightweightDispatcher.processMouseEvent(Container.java:4492)
    at java.awt.LightweightDispatcher.dispatchEvent(Container.java:4422)
    at java.awt.Container.dispatchEventImpl(Container.java:2273)
    at java.awt.Window.dispatchEventImpl(Window.java:2719)
    at java.awt.Component.dispatchEvent(Component.java:4687)
    at java.awt.EventQueue.dispatchEventImpl(EventQueue.java:735)
    at java.awt.EventQueue.access$200(EventQueue.java:103)
    at java.awt.EventQueue$3.run(EventQueue.java:694)
    at java.awt.EventQueue$3.run(EventQueue.java:692)
    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:708)
    at java.awt.EventQueue$4.run(EventQueue.java:706)
    at java.security.AccessController.doPrivileged(Native Method)
    at java.security.ProtectionDomain$1.doIntersectionPrivilege(ProtectionDomain.java:76)
    at java.awt.EventQueue.dispatchEvent(EventQueue.java:705)
    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)

Answer 1

更改当前代码

while((line= br.readLine())!=null)
{
    x++;
    if(line.charAt(x)=='\n')
        fw.write('\n');
    else
        fw.write(line+"\n");
}

至

 while((line= br.readLine())!=null) {             
     fw.write(line+"\n");
 }