来自JAR内文件夹的随机文件

import java.io.IOException;
import java.io.InputStream;
import java.util.Random;
import java.util.jar.JarEntry;
import java.util.jar.JarFile;

public class RandomFileFromJar {
    public static void main(String[] args) {
        try {
            JarFile jarFile = new JarFile("yourJarFile.jar");
            String folderName = "yourFolderName";
            JarEntry[] entries = jarFile.entries();
            int numFiles = 0;
            for (JarEntry entry : entries) {
                if (entry.getName().startsWith(folderName + "/")) {
                    numFiles++;
                }
            }
            Random random = new Random();
            int randomIndex = random.nextInt(numFiles);
            int currentIndex = 0;
            for (JarEntry entry : entries) {
                if (entry.getName().startsWith(folderName + "/")) {
                    if (currentIndex == randomIndex) {
                        InputStream inputStream = jarFile.getInputStream(entry);
                        // 在这里可以对获取到的随机文件进行处理
                        break;
                    }
                    currentIndex++;
                }
            }
            jarFile.close();
        } catch (IOException e) {
            e.printStackTrace();
        }
    }
}