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我查看了如何访问 JAR 文件中的资源？以及如何将文本文件从 jar 复制到 jar 之外的文件中？和许多其他问题，但实际上无法得到答案。我要做的是将jar中的文件内容复制res/CDC.txt到jar中的某个地方。现在，在我的电脑上它可以工作，但是当我在不同的电脑上尝试它时，我得到了FileNotFoundException. 所以，我弄清楚了为什么它对我有用。我有一个 CLASSPATH 设置为.;D:\myname\Java\JavaFiles我所有的 java 文件位于包中的位置。在“JavaFiles”目录中还有“res/CDC.txt”。因此，当我启动我的应用程序时，它首先检查 myapp.jar 所在的当前目录中的“res/CDC.txt”，然后检查“JavaFiles”并找到它。其他电脑没有。所以，

public final class CT
{

//Other fields
private static CT ct;
private NTSystem nts;
private File f1;
private File f6;
private PrintWriter pw1;
private BufferedReader br1;
//Other fields

public static void main(String[] args)
{
    try
    {
        showMessage("Executing program...");
        ct = new CT();
        ct.init();
        ct.create();
        ct.insertData();
        //Other code
        showMessage("Program executed!");
    }
    catch(Exception e)
    {
        showMessage("An exception occured! Program closed.");
        e.printStackTrace();
        System.exit(0);
    }
}

private void init()
    throws IOException
{
    //Other initialization
    nts = new NTSystem();
    f1 = new File("C:\\Users\\" + nts.getName() + "\\blahblah");
    f6 = new File("res\\CDC.txt");
    br1 = new BufferedReader(new FileReader(f6));
    //Other initialization
    showMessage("Initialized");
}

private void create()
    throws IOException
{
    //Makes sure file/dir exists, etc

    pw1 = new PrintWriter(new BufferedWriter(new FileWriter(f1)), true);
    //Other Stuff

    showMessage("Created");
}

private void insertData()
    throws IOException
{
    String line = br1.readLine();
    while(line != null)
    {
        pw1.println(line);
        line = br1.readLine();
    }

    //Other stuff
    showMessage("Data inserted");
}

private static void showMessage(String msg)
{
    System.out.println(msg);
}

}

我改成

public final class CT
{

//Other fields
private static CT ct;
private NTSystem nts;
private byte[] buffer;
private File f1;
private URL url1;
private FileOutputStream fos1;
private InputStream is1;
//Other fields

public static void main(String[] args)
{
    try
    {
        showMessage("Executing program...");
        ct = new CT();
        ct.init();
        ct.create();
        ct.insertData();
        //Other code
        showMessage("Program executed!");
    }
    catch(Exception e)
    {
        showMessage("An exception occured! Program closed.");
        e.printStackTrace();
        System.exit(0);
    }
}

private void init()
    throws IOException
{
    //Other initialization
    nts = new NTSystem();
    buffer = new byte[4096];
    f1 = new File("C:\\Users\\" + nts.getName() + "\\blahblah");
    url1 = getClass().getClassLoader.getResource("res\\CDC.txt"); //Also tried url1 = ct.getClass().getClassLoader.getResource("res\\CDC.txt"); or url1 = this.getClass().getClassLoader.getResource("res\\CDC.txt"); or url1 = CT.getClass().getClassLoader.getResource("res\\CDC.txt");
    is1 = url1.openStream();
    //Other initialization
    showMessage("Initialized");
}

private void create()
    throws IOException
{
    //Makes sure file/dir exists, etc

    pw1 = new PrintWriter(new BufferedWriter(new FileWriter(f1)), true);
    //Other Stuff

    showMessage("Created");
}

private void insertData()
    throws IOException
{
    int read = is1.read(buffer);
    while(line != null)
    {
        fos1.write(buffer, 0, read);
        read = is1.read(buffer);
    }

    //Other stuff
    showMessage("Data inserted");
}

private static void showMessage(String msg)
{
    System.out.println(msg);
}

}

而这一次我总是得到NullPointerException。那么，如何读取 jar 中的文件夹和文件呢？

谢谢

4

1 回答 1

0

您将需要使用getSystemResourceAsStream()从 jar 中的文件中读取内容。

这当然是假设文件实际上位于其他用户计算机的类路径上。

于 2012-08-16T15:20:45.797 回答