Question

我只是在第4天的java，所以我几乎是初学者。我一直试图让Jlist项目写在文本文件中，但没有运气。这就是我目前正在尝试的：

public void actionPerformed(ActionEvent e) {
            for (int j = 0 ; j<list.getItemCount() ; j++)
            {

                try {
                    File file = new File(listname + ".txt");
                    FileWriter fileWriter = new FileWriter(file);
                    PrintWriter printWriter = new PrintWriter(fileWriter);
                    String email1 =list.getItem(j).toString();
                    printWriter.print(email1);
                    printWriter.print("\n");
                    fileWriter.flush();
                    fileWriter.close();
                } catch (IOException l) {
                    l.printStackTrace();
                }
            }
        }

我收到此错误：

java.io.FileNotFoundException: javax.swing.JTextField[,823,7,210x20,layout=javax.swing.plaf.basic.BasicTextUI$UpdateHandler,alignmentX=0.0,alignmentY=0.0,border=javax.swing.plaf.BorderUIResource$CompoundBorderUIResource@56d4941f,flags=296,maximumSize=,minimumSize=,preferredSize=,caretColor=sun.swing.PrintColorUIResource[r=51,g=51,b=51],disabledTextColor=javax.swing.plaf.ColorUIResource[r=184,g=207,b=229],editable=true,margin=javax.swing.plaf.InsetsUIResource[top=0,left=0,bottom=0,right=0],selectedTextColor=sun.swing.PrintColorUIResource[r=51,g=51,b=51],selectionColor=javax.swing.plaf.ColorUIResource[r=184,g=207,b=229],columns=10,columnWidth=11,command=,horizontalAlignment=LEADING].txt (The filename, directory name, or volume label syntax is incorrect)
at java.io.FileOutputStream.open0(Native Method)
at java.io.FileOutputStream.open(FileOutputStream.java:270)
at java.io.FileOutputStream.<init>(FileOutputStream.java:213)
at java.io.FileOutputStream.<init>(FileOutputStream.java:162)
at java.io.FileWriter.<init>(FileWriter.java:90)
at com.example.tests.InstagramAievx$12.actionPerformed(InstagramAievx.java:343)
at javax.swing.AbstractButton.fireActionPerformed(AbstractButton.java:2022)
at javax.swing.AbstractButton$Handler.actionPerformed(AbstractButton.java:2348)
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:6535)
at javax.swing.JComponent.processMouseEvent(JComponent.java:3324)
at java.awt.Component.processEvent(Component.java:6300)
at java.awt.Container.processEvent(Container.java:2236)
at java.awt.Component.dispatchEventImpl(Component.java:4891)
at java.awt.Container.dispatchEventImpl(Container.java:2294)
at java.awt.Component.dispatchEvent(Component.java:4713)
at java.awt.LightweightDispatcher.retargetMouseEvent(Container.java:4888)
at java.awt.LightweightDispatcher.processMouseEvent(Container.java:4525)
at java.awt.LightweightDispatcher.dispatchEvent(Container.java:4466)
at java.awt.Container.dispatchEventImpl(Container.java:2280)
at java.awt.Window.dispatchEventImpl(Window.java:2750)
at java.awt.Component.dispatchEvent(Component.java:4713)
at java.awt.EventQueue.dispatchEventImpl(EventQueue.java:758)
at java.awt.EventQueue.access$500(EventQueue.java:97)
at java.awt.EventQueue$3.run(EventQueue.java:709)
at java.awt.EventQueue$3.run(EventQueue.java:703)
at java.security.AccessController.doPrivileged(Native Method)
at java.security.ProtectionDomain$JavaSecurityAccessImpl.doIntersectionPrivilege(ProtectionDomain.java:76)
at java.security.ProtectionDomain$JavaSecurityAccessImpl.doIntersectionPrivilege(ProtectionDomain.java:86)
at java.awt.EventQueue$4.run(EventQueue.java:731)
at java.awt.EventQueue$4.run(EventQueue.java:729)
at java.security.AccessController.doPrivileged(Native Method)
at java.security.ProtectionDomain$JavaSecurityAccessImpl.doIntersectionPrivilege(ProtectionDomain.java:76)
at java.awt.EventQueue.dispatchEvent(EventQueue.java:728)
at java.awt.EventDispatchThread.pumpOneEventForFilters(EventDispatchThread.java:201)
at java.awt.EventDispatchThread.pumpEventsForFilter(EventDispatchThread.java:116)
at java.awt.EventDispatchThread.pumpEventsForHierarchy(EventDispatchThread.java:105)
at java.awt.EventDispatchThread.pumpEvents(EventDispatchThread.java:101)
at java.awt.EventDispatchThread.pumpEvents(EventDispatchThread.java:93)
at java.awt.EventDispatchThread.run(EventDispatchThread.java:82)

当我用

运行代码时

printWriter.print("actual string");

有效。但是，当我尝试放入Jlist项目时。有帮助吗？谢谢！

更新：我的第一个错误是当我纠正它时忘记做listname.getText()。现在它写入文件，但它只写入添加到列表中的最后一项。任何想法??

Answer 1

您正在覆盖列表中每个元素的文件。您需要在循环外移动打开和关闭文件：

public void actionPerformed(ActionEvent e) {
    try {
        File file = new File(listname + ".txt");
        FileWriter fileWriter = new FileWriter(file);
        PrintWriter printWriter = new PrintWriter(fileWriter);
        for (int j = 0 ; j<list.getItemCount() ; j++)
        {
            String email1 =list.getItem(j).toString();
            printWriter.print(email1);
            printWriter.print("\n");
        }
        fileWriter.flush();
        fileWriter.close();
    } catch (IOException l) {
    l.printStackTrace();
}

无法将列表项获取到txt文件

1 个答案: