导出 .jar 时出现 FileNotFoundException [英] FileNotFoundException when exporting .jar

问题描述

在我的客户端/服务器应用程序中，我需要从客户端向服务器发送一些文件(.txt、.doc 等).当我在 Eclipse 中运行我的代码时，它可以工作，但是当我导出 Applet 的签名 JAR 时，它却没有.它抛出一个 FileNotFoundException.我尝试以多种方式保存文件但没有成功.

In my client/server app I need to send some file (.txt, .doc, etc.) from the client to the server. When I run my code in Eclipse it works, but when I export the signed JAR of the Applet it doesn't. It throws a FileNotFoundException. I tried saving file in several ways without success.

public static boolean saveFile(File sourceFile) throws IOException {

    DirectoryChooserDialog dialog = new DirectoryChooserDialog();
    filePath = dialog.getDestinationFolder();
    if (filePath != null) {
        InputStream inputFile = ClassLoader.getSystemResourceAsStream(""+sourceFile);

        filePath += File.separator + sourceFile.getName();

        FileOutputStream outputFile = new FileOutputStream(filePath);

        int byteLetti = 0;
        while ((byteLetti = inputFile.read(buffer)) >= 0) {
            outputFile.write(buffer, 0, byteLetti);
            outputFile.flush();
        }

        inputFile.close();

        outputFile.close();

        return true;
    } else
        return false;
}

使用的替代代码:

FileInputStream inputFile = new FileInputStream(sourceFile);

或

InputStream inputFile = ClassLoader.class.getResourceAsStream(""+sourceFile);

或者

InputStream inputFile = FileSaving.class.getResourceAsStream(""+sourceFile);

原始代码和所有替代代码在 Eclipse 中都可以工作，并且在导出时停止工作.

Original code and every alternative work in Eclipse and stop working when exported.

推荐答案

此代码正在查找类路径上的文件.如果那里没有文件，它会抛出 FNF.当您在 Eclipse 中工作时，您的文件可能在 src 中，因此它会被复制到 bin.将文件归档到 jar 后，您可以访问它 getResource 或 getResourceAsStream

This code is looking a file on the classpath. If there's no a file there it throws FNF. When you work in Eclipse your file is probably in the src, so it's copied to bin. After you archived a file to the jar you can access it either getResource or getResourceAsStream

InputStream inputFile = this.getClass().getClassLoader().getResourceAsStream(sourceFile.getName())

或使用网址.例如

URL url = new URL("jar:file:/c:/path/to/my.jar!/myfile.txt"); 
JarURLConnection conn = (JarURLConnection)url.openConnection();
InputStream inputFile = conn.getInputStream();

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