यह जावा वर्ग सभी WAR सामग्री और JAR की सामग्री को निर्देशिकाओं की सूची के तहत स्कैन करता है, और प्रत्येक घटक के लिए जावा वर्ग फ़ाइल संस्करणों का सारांश WARs के भीतर प्रत्येक JAR शामिल करता है:
public class ShowClassVersions {
private static final byte[] CLASS_MAGIC = new byte[] {(byte)0xca, (byte)0xfe, (byte)0xba, (byte)0xbe};
private final byte[] bytes = new byte[8];
private TreeMap<String,ArrayList<String>> vers = new TreeMap<>();
private void scan(Path f) throws IOException {
if (Files.isDirectory(f)) {
Pattern pattern = Pattern.compile("\\.[wj]ar$"); // or |\\.class
try(var stream = Files.find(f, Integer.MAX_VALUE, (p,a) -> a.isRegularFile() && pattern.matcher(p.toString()).find())) {
stream.forEach(this::scanFile);
}
return;
}
scanFile(f);
}
private void scanFile(Path f) {
String fn = f.getFileName().toString();
try {
if (fn.endsWith(".jar"))
scanArchive(f);
else if (fn.endsWith(".war"))
scanArchive(f);
else if (fn.endsWith(".class"))
record(f, versionOfClass(f));
} catch (IOException e) {
throw new UncheckedIOException(e);
}
}
private void scanArchive(Path p) throws IOException {
try(InputStream in = Files.newInputStream(p)) {
scanArchive(p.toAbsolutePath().toString(), in);
}
}
private String scanArchive(String desc, InputStream in) throws IOException {
String version = null;
ZipInputStream zip = new ZipInputStream(in);
ZipEntry entry = null;
while ((entry = zip.getNextEntry()) != null) {
String name = entry.getName();
if (version == null && name.endsWith(".class")) {
version = versionOfClass(zip);
}
else if (name.endsWith(".jar")) {
scanArchive(desc+" ==>> "+name, zip);
}
}
if (version != null)
record(desc, version);
return version;
}
private String versionOfClass(Path p) throws IOException {
String version = null;
try(InputStream in = Files.newInputStream(p)) {
version = versionOfClass(in);
}
return version;
}
private String versionOfClass(InputStream in) throws IOException {
String version = null;
int c = in.read(bytes);
if (c == bytes.length && Arrays.mismatch(bytes, CLASS_MAGIC) == CLASS_MAGIC.length) {
int minorVersion = (bytes[4] << 8) + (bytes[4] << 0);
int majorVersion = (bytes[6] << 8) + (bytes[7] << 0);
version = ""+majorVersion + "." + minorVersion;
}
return version;
}
private void record(String p, String v) {
vers.computeIfAbsent(String.valueOf(v), k -> new ArrayList<String>()).add(p);
}
private void record(Path p, String v) {
record(p.toAbsolutePath().toString(), v);
}
public static void main(String[] args) throws IOException {
ShowClassVersions v = new ShowClassVersions();
var files = Arrays.stream(args).map(Path::of).collect(Collectors.toList());
for (var f : files) {
v.scan(f);
}
for (var ver : v.vers.keySet()) {
System.out.println("Version: "+ver);
for (var p : v.vers.get(ver)) {
System.out.println(" "+p);
}
};
}
}
