我做了一个自动下载器，它将所有数据保存到user.home / OSR.cache 它使用Dropbox下载zip并将其解压缩到特定文件夹。 我的问题是，它尝试下载zip，但将其保存到0字节的目录中，再次检查了链接，它也开始下载，因此我不确定这里的问题是什么？ 这是我的更新程序类
public class Updater {
/**
* The client version.
*/
private static final String CLIENT_VERSION = "https://www.dropbox.com/s/j99anix5sngmktv/clientVersion.txt?dl=1";
/**
* The cache version.
*/
private static final String CACHE_VERSION = "https://www.dropbox.com/s/6nfd34bantevv2i/cacheVersion.txt?dl=1";
/**
* The cache download url link.
*/
public static final String CACHE_LINK = "https://www.dropbox.com/s/gsxglfqelnnnae4/TempCache5945.zip?dl=1";
/**
* The client download url link.
*/
private static final String CLIENT_LINK = "https://www.dropbox.com/s/ctdiirkasrf1grh/Client.jar?dl=1";
/**
* The cache directory.
*/
private static final File CACHE_DIRECTORY = new File(Utility.findcachedir());
/**
* The current update state.
*/
public UpdateState state = UpdateState.CHECK_FOR_UPDATES;
/**
* An instance of updater
*/
private static final Updater INSTANCE = new Updater();
/**
* Constructs a new {@link Updater}.
*/
private Updater() {
/* can't initialize this class. */
}
public void setup(Client client) {
client.updaterRenderer = new UpdaterRenderer(client, client.graphics);
if (Client.virgin) {
state = UpdateState.WELCOME_SCREEN;
client.updaterRenderer.setScreen(new WelcomeUpdateScreen());
} else {
state = UpdateState.DEFAULT_SCREEN;
client.updaterRenderer.setScreen(new DefaultUpdateScreen());
}
}
public void checkForUpdates() {
Client client = Client.instance;
if (checkClientUpdates()) {
UpdateComponent screen = new ClientUpdateScreen();
client.updaterRenderer.setScreen(screen);
try {
final String path = getClass().getProtectionDomain().getCodeSource().getLocation().toURI().getPath();
updateClient(path.substring(path.lastIndexOf("/") + 1, path.indexOf(".jar")), screen);
} catch (URISyntaxException e) {
e.printStackTrace();
}
} else if (checkCacheUpdate()) {
UpdateComponent screen = new CacheUpdateScreen();
client.updaterRenderer.setScreen(screen);
try {
updateCache(screen);
} catch (IOException e) {
e.printStackTrace();
}
}
finish();
}
public void finish() {
if (Client.virgin) {
UpdateComponent screen = new GoodbyeUpdateScreen();
Client.instance.updaterRenderer.setScreen(screen);
return;
}
if (state != UpdateState.FINISHED) {
Client client = Client.instance;
Client.updaterScreenIP = null;
client.updaterRenderer.finish();
client.updaterRenderer = null;
System.gc();
System.runFinalization();
client.startUp();
state = UpdateState.FINISHED;
}
}
public static boolean isActive() {
return get().state != UpdateState.FINISHED;
}
/**
* Checks the web server for client jar updates.
*/
private boolean checkClientUpdates() {
if (Configuration.DEBUG_MODE) {
return false;
}
int clientVersion = Integer.parseInt(Utility.getNewestVersion(CLIENT_VERSION));
int current = Configuration.CLIENT_VERSION;
System.out.println(clientVersion + " " + current);
// Incorrect client version
if (current != clientVersion) {
System.out.println("Client update required!");
state = UpdateState.UPDATE_CLIENT;
}
return state == UpdateState.UPDATE_CLIENT;
}
/**
* Checks the web server for cache updates.
*/
private boolean checkCacheUpdate() {
if (Configuration.DEBUG_MODE) {
return false;
}
File dat = new File(Utility.findcachedir() + Configuration.SPRITE_FILE_NAME + ".dat");
File idx = new File(Utility.findcachedir() + Configuration.SPRITE_FILE_NAME + ".idx");
// do the sprite files exist?
if (!dat.exists() || !idx.exists()) {
System.out.println("Cache sprite files do not exist!");
state = UpdateState.UPDATE_CACHE;
return true;
}
File versionFile = new File(Utility.findcachedir() + "version.dat");
// check if the version file exists
if (!versionFile.exists()) {
System.out.println("Version file does not exist!");
state = UpdateState.UPDATE_CACHE;
return true;
}
String version = Utility.getNewestVersion(CACHE_VERSION);
String current = Utility.getCurrentVersion(Utility.findcachedir() + "version.dat");
// does the version of the cache match the updated version
if (!current.equalsIgnoreCase(version)) {
System.out.println("Version file mismatch!");
state = UpdateState.UPDATE_CACHE;
return true;
}
return state == UpdateState.UPDATE_CACHE;
}
/**
* Updates the current client jar file with the new downloaded one.
*
* @param jarName the name of this jar file
*/
private void updateClient(String jarName, UpdateComponent screen) {
File client = new File(System.getProperty("user.dir") + File.separator + jarName + ".jar");
try {
File temp = File.createTempFile("tmp", Long.toString(System.nanoTime()));
temp.deleteOnExit();
download(CLIENT_LINK, temp, screen);
replaceData(temp, client);
Runtime.getRuntime().exec("java -jar " + jarName + ".jar");
} catch (IOException e) {
e.printStackTrace();
}
System.exit(0);
}
public void updateCache(UpdateComponent screen) throws IOException {
File temp = File.createTempFile("tmp", Long.toString(System.nanoTime()));
temp.deleteOnExit();
download(CACHE_LINK, temp, screen);
unZipFile(temp, CACHE_DIRECTORY, (CacheUpdateScreen) screen);
try {
File file = new File(Utility.findcachedir() + File.separator + "version.dat");
BufferedWriter out = new BufferedWriter(new FileWriter(file));
out.write("" + Configuration.CACHE_VERSION);
out.close();
} catch (Exception e) {
e.printStackTrace();
}
state = UpdateState.UP_TO_DATE;
Client.instance.updaterRenderer.setScreen(new UpToDateUpdateScreen());
System.out.println("Cache was downloaded and extracted successfully.");
}
private void download(String link, File target, UpdateComponent screen) {
try {
URL url = new URL(link);
URLConnection conn = url.openConnection();
BufferedInputStream in = new BufferedInputStream(conn.getInputStream());
FileOutputStream out = new FileOutputStream(target);
if (state == UpdateState.UPDATE_CLIENT) {
screen.setLabel("Downloading client files");
} else if (state == UpdateState.UPDATE_CACHE) {
screen.setLabel("Downloading cache files");
}
int length;
long downloaded = 0;
int total = conn.getContentLength();
byte[] bytes = new byte[1024];
while ((length = in.read(bytes)) != -1) {
out.write(bytes, 0, length);
downloaded += length;
if (state == UpdateState.UPDATE_CLIENT) {
((ClientUpdateScreen) screen).setProgress((int) ((downloaded / (double) total * 100)));
} else if (state == UpdateState.UPDATE_CACHE) {
((CacheUpdateScreen) screen).setProgress((int) ((downloaded / (double) total * 100)));
}
}
in.close();
out.flush();
out.close();
} catch (Exception e) {
e.printStackTrace();
}
}
private void unZipFile(File zip, File directory, CacheUpdateScreen screen) throws IOException {
screen.setLabel("Extracting cache files");
screen.setProgress(0);
byte[] bytes = new byte[1024];
ZipEntry entry;
ZipInputStream in = new ZipInputStream(new BufferedInputStream(new FileInputStream(zip)));
while ((entry = in.getNextEntry()) != null) {
File file = new File(directory, entry.getName());
if (entry.isDirectory()) {
if (!file.mkdirs()) {
System.err.println("Could not create directory '" + file.toPath() + "'!");
}
} else {
FileOutputStream out = new FileOutputStream(file);
int len;
long unzipped = 0;
long total = entry.getSize();
while ((len = in.read(bytes)) > -1) {
out.write(bytes, 0, len);
unzipped += len;
screen.setProgress((int) (unzipped / (double) total * 100));
}
out.flush();
out.close();
}
}
in.close();
}
/**
* Replaces the contents of the source file into the target file.
*
* @param source the source file
* @param target the target file
* @throws IOException if there was an exception replacing the files
*/
private static void replaceData(File source, File target) throws IOException {
ZipEntry entry;
int length;
byte[] buffer = new byte[1024];
try (ZipInputStream in = new ZipInputStream(new BufferedInputStream(new FileInputStream(source))); ZipOutputStream out = new ZipOutputStream(new BufferedOutputStream(new FileOutputStream(target)))) {
while ((entry = in.getNextEntry()) != null) {
if (entry.isDirectory())
continue;
ByteArrayOutputStream bytes = new ByteArrayOutputStream();
while ((length = in.read(buffer, 0, buffer.length)) > -1) {
bytes.write(buffer, 0, length);
}
out.putNextEntry(entry);
out.write(bytes.toByteArray());
out.closeEntry();
}
out.finish();
}
}
public static Updater get() {
return INSTANCE;
}
}
还有我的Utility类findcachedir方法
public static String findcachedir() {
File file = new File(System.getProperty("user.home") + "/OSR.Cache/");
if (!file.exists()) {
if (!file.mkdir()) {
return secondDir();
}
Client.virgin = true;
}
return System.getProperty("user.home") + "/OSR.Cache/";
}
public static String secondDir() {
File file = new File("c:/OSR.Cache/");
if (!file.exists() && file.mkdir())
Client.virgin = true;
return file.toString();
}
有人能启发我为什么它没有被保存吗？