Question

我用这个片段展示了一个JFileChooser：

public File getDestination() {
    JFileChooser chooser = new JFileChooser();
    chooser.setFileSelectionMode(JFileChooser.DIRECTORIES_ONLY);
    int option = chooser.showSaveDialog(null);
    if(option == JFileChooser.APPROVE_OPTION) {
        return chooser.getSelectedFile().getAbsolutePath();
    }
    return new File(".");
}

通常，它第一次显示时，显示＆amp;工作正常。第二次，它将始终抛出此异常：

Exception in thread "Basic L&F File Loading Thread" java.lang.NullPointerException
    at sun.awt.shell.Win32ShellFolder2.pidlsEqual(Unknown Source)
    at sun.awt.shell.Win32ShellFolder2.equals(Unknown Source)
    at sun.awt.shell.Win32ShellFolderManager2.isFileSystemRoot(Unknown Source)
    at sun.awt.shell.ShellFolder.isFileSystemRoot(Unknown Source)
    at javax.swing.filechooser.FileSystemView.isFileSystemRoot(Unknown Source)
    at javax.swing.filechooser.WindowsFileSystemView.isTraversable(Unknown Source)
    at javax.swing.JFileChooser.isTraversable(Unknown Source)
    at javax.swing.plaf.basic.BasicDirectoryModel$LoadFilesThread.run0(Unknown Source)
    at javax.swing.plaf.basic.BasicDirectoryModel$LoadFilesThread.run(Unknown Source)

Java -version说：

java version "1.6.0_20"
Java(TM) SE Runtime Environment (build 1.6.0_20-b02)
Java HotSpot(TM) Client VM (build 16.3-b01, mixed mode, sharing)

我找到的帖子here说我应该降级Java版本。我应该听从他们的意见，还是有什么我可以做错的？

Answer 1

这在build 1.6u21

中得到修复

见这里： http://bugs.sun.com/bugdatabase/view_bug.do?bug_id=6940843

Answer 2

这看起来真的是版本问题/回归。所以答案就是：遵循他们的建议，你没有做错任何事情;）

显示JFileChooser时出现NullPointerException

2 个答案: