英文:

Updating a JList with Files

问题

我正在为学校项目尝试制作一个小程序，用于提取文件。我正在使用一个 JList 来显示所有提取的文件，但在经过很多小时的探索后，我无法弄清楚如何在文件夹中出现新文件时使这个 JList 更新。由于批处理文件（实际提取程序）需要不同的时间来完成，它在按钮的 ActionListener 中不能正确刷新。我该如何让它工作？

这是我用于查找特定扩展名文件的类：
```java
public class fileFinder {
    public static String[] thing() {
        File file = new File(".\\at9snfsbs");
        File[] files = file.listFiles(new FilenameFilter() {

            @Override
            public boolean accept(File dir, String name) {
                if (name.toLowerCase().endsWith(".at9")) {
                    return true;
                } else {
                    return false;
                }
            }
        });
        String[] fileNames = new String[files.length];
        for (int i = 0; i < files.length; i++) {
            fileNames[i] = files[i].getName();
        }

        return fileNames;
    }
}

这是 JList：

DefaultListModel model = new DefaultListModel();
String[] things = fileFinder.thing();
for (int i = 0; i < things.length; i++) {
    model.addElement(things[i]);
}
JList list = new JList(model);
list.setSelectionMode(ListSelectionModel.SINGLE_SELECTION);
scrollPane.setViewportView(list);

这是一个按钮的 ActionListener，它启动一个批处理文件，该文件是实际的转换器：

try {
    Runtime.getRuntime().exec("cmd /c start .\\at9snfsbs\\shit.bat");
    String[] thang = fileFinder.thing();
    model.clear();
    for (int i = 0; i < thang.length; i++) {
        model.addElement(thang[i]);
    };
} catch (IOException e1) {
    e1.printStackTrace();
}

我在编码方面没有经验或者水平不高，所以任何帮助都将不胜感激！

<details>
<summary>英文:</summary>

I&#39;m trying to make a little program for a school project that extracts files. I&#39;m using a JList to display all the extracted files but after lots of hours lurking I can&#39;t figure out how to make this JList update when there are new files present in the folder. It doesn&#39;t refresh properly in the button&#39;s ActionListener since the batch file (the actual extractor) takes a varied amount of time to finish. How can I get this to work?

This is the class I&#39;m using to find files of certain extension:

public class fileFinder {
public static String[] thing() {
File file = new File(".\at9snfsbs");
File[] files = file.listFiles(new FilenameFilter() {

		@Override
		public boolean accept(File dir, String name) {
			if (name.toLowerCase().endsWith(".at9")) {
				return true;
			} else {
				return false;
			}
		}
	});
	String[] fileNames = new String[files.length];
	for (int i = 0; i < files.length; i++) {
		fileNames[i] = files[i].getName();
	}

	return fileNames;
}

}

This is the JList:

	DefaultListModel model = new DefaultListModel();
	String[] things = fileFinder.thing();
	for (int i = 0; i < things.length; i++) {
		model.addElement(things[i]);
	}
	JList list = new JList(model);
	list.setSelectionMode(ListSelectionModel.SINGLE_SELECTION);
	scrollPane.setViewportView(list);

And this is a button's ActionListener that starts a batch file which is the actual converter:

try {
Runtime.getRuntime().exec("cmd /c start .\at9snfsbs\shit.bat");
String[] thang = fileFinder.thing();
model.clear();
for (int i = 0; i < thang.length; i++) {
model.addElement(thang[i]);
};
} catch (IOException e1) {
e1.printStackTrace();
}

I'm not experienced or good in coding so any help would be appreciated!

</details>


# 答案1
**得分**: 0

&gt; Andrew Thompson: 另请参阅[当Runtime.exec()无法正常工作时](http://www.javaworld.com/article/2071275/core-java/when-runtime-exec---won-t.html)，了解有关正确创建和处理进程的许多有用提示。然后忽略它提到的 `exec`，并使用 `ProcessBuilder` 来创建该进程。还要将 `String arg` 拆分为 `String[] args`，以考虑包含空格字符的路径等情况。

我使用 `ProcessBuilder` 和 `waitFor()` 使其工作正常。

<details>
<summary>英文:</summary>

&gt; Andrew Thompson: See also [When Runtime.exec() won&#39;t](http://www.javaworld.com/article/2071275/core-java/when-runtime-exec---won-t.html) for many good tips on creating and handling a process correctly.  Then ignore it refers to `exec` and use a `ProcessBuilder` to create the process. Also break a `String arg` into `String[] args` to account for things like paths containing space characters.

 I got it working with a `ProcessBuilder` and `waitFor()`.

</details>