无法从 JAR 文件中读取自定义 Manifest 属性的原因及解决方案

import java.io.*;
import java.net.URI;
import java.net.URISyntaxException;
import java.nio.file.*;
import java.nio.file.attribute.BasicFileAttributes;
import java.util.HashMap;
import java.util.Map;
import java.util.jar.JarFile;
import java.util.jar.Manifest;
import java.nio.file.StandardCopyOption;

public class ManifestModifier {

    public static void main(String[] args) throws IOException, URISyntaxException {
        File jar = new File("C:\Users\employee1234\Desktop\auth-0.1.3.jar");
        String testVersion = "1.2.3";

        Map<String, String> env = new HashMap<>();
        env.put("create", "true");

        // Mount the jar
        try (FileSystem fileSystem = FileSystems.newFileSystem(jarFileToURI(jar), env)) {
            // Read the manifest
            ByteArrayOutputStream byteArrayOutputStream = new ByteArrayOutputStream();
            Path manifestPath = fileSystem.getPath("/META-INF/MANIFEST.MF");
            Files.copy(manifestPath, byteArrayOutputStream);

            // Convert the manifest bytes to a string and construct a string builder
            StringBuilder manifestData = new StringBuilder(byteArrayOutputStream.toString().trim());
            // Add the custom manifest attribute, ensuring proper line breaks
            manifestData.append("
");
            manifestData.append("Deployments-Version: ").append(testVersion).append("
");
            //Ensure the end of the file also has a new line character.
            manifestData.append("
");

            // Write the manifest back to the jar
            Files.copy(new ByteArrayInputStream(manifestData.toString().getBytes()), manifestPath,
                    StandardCopyOption.REPLACE_EXISTING);

            // Try-with-resources closes the mounted jar
        }

        // This part should now work
        try (JarFile jarFile = new JarFile(jar)) {
            Manifest manifest = jarFile.getManifest();
            System.out.println(manifest.getMainAttributes().getValue("Deployments-Version"));
        }
    }

    // Stolen from java.io.File with some modifications
    private static URI jarFileToURI(File jarFile) throws URISyntaxException {
        String sp = slashify(jarFile.getAbsoluteFile().getPath(), false);
        if (sp.startsWith("//"))
            sp = "//" + sp;
        return new URI("jar:file", null, sp, null);
    }

    // Stolen from java.io.File;
    private static String slashify(String path, boolean isDirectory) {
        String p = path;
        if (File.separatorChar != '/')
            p = p.replace(File.separatorChar, '/');
        if (!p.startsWith("/"))
            p = "/" + p;
        if (!p.endsWith("/") && isDirectory)
            p = p + "/";
        return p;
    }
}

manifestData.append("
");
manifestData.append("Deployments-Version: ").append(testVersion).append("
");
manifestData.append("
");