//文件复制解析，复制文件到cache　directory 中 ,VM options : -Dvertx.disableFileCPResolving
public static final String DISABLE_CP_RESOLVING_PROP_NAME = "vertx.disableFileCPResolving";
private static final boolean ENABLE_CP_RESOLVING = !Boolean.getBoolean(DISABLE_CP_RESOLVING_PROP_NAME);/*** enableCaching 文件解析器是否用缓存，默认ture, * 设置两种方式:一、VertxOptions类的setFileResolverCachingEnabled方法*　二、设置system property,VM options "-Dvertx.disableFileCaching",对原代码无侵入性*/
public FileResolver(Vertx vertx, boolean enableCaching) {this.vertx = vertx;this.enableCaching = enableCaching;//获取工作目录 -Dvertx.cwdString cwdOverride = System.getProperty("vertx.cwd");if (cwdOverride != null) {cwd = new File(cwdOverride).getAbsoluteFile();} else {cwd = null;}if (ENABLE_CP_RESOLVING) {setupCacheDir();}
}/***  建立cache目录*/
private void setupCacheDir() {//CACHE_DIR_BASE 通过-Dvertx.cacheDirBase设置，默认当前工作目录 .vertx隐藏目录下String cacheDirName = CACHE_DIR_BASE + "/file-cache-" + UUID.randomUUID().toString();cacheDir = new File(cacheDirName);if (!cacheDir.mkdirs()) {throw new IllegalStateException("Failed to create cache dir");}// 添加 shutdown hook，kill -15 pid 触发缓存清理shutdownHook = new Thread(() -> {CountDownLatch latch = new CountDownLatch(1);deleteCacheDir(ar -> latch.countDown());try {latch.await(10, TimeUnit.SECONDS);} catch (Exception ignore) {}});Runtime.getRuntime().addShutdownHook(shutdownHook);
}/*** 删除cache目录*/
private void deleteCacheDir(Handler<AsyncResult<Void>> handler) {if (cacheDir != null && cacheDir.exists()) {vertx.fileSystem().deleteRecursive(cacheDir.getAbsolutePath(), true, handler);} else {handler.handle(Future.succeededFuture());}
}

/***　解析文件*/
public File resolveFile(String fileName) {// 现在disk查找文件File file = new File(fileName);if (cwd != null && !file.isAbsolute()) {//是否是绝对路径file = new File(cwd, fileName);}// -Dvertx.disableFileCPResolving 设置if (!ENABLE_CP_RESOLVING) {return file;}/*** synchronized同步块，防止多线程对cache directory操作导致线程安全问题*/synchronized (this) {if (!file.exists()) {// 首先本地文件cache　查找File cacheFile = new File(cacheDir, fileName);if (enableCaching && cacheFile.exists()) {return cacheFile;}// 在classpath 查找ClassLoader cl = getClassLoader();//检查是否是UNIX separator,不是将文件路径 \ 替换为 /,不同操作系统 separator 存在差异if (NON_UNIX_FILE_SEP) {fileName = fileName.replace(FILE_SEP, "/");}String parentFileName = file.getParent();if (parentFileName != null) {//缓存父目录中存在的所有资源URL directoryContents = cl.getResource(parentFileName);if (directoryContents != null) {unpackUrlResource(directoryContents, parentFileName, cl, true);}}URL url = cl.getResource(fileName);if (url != null) {return unpackUrlResource(url, fileName, cl, false);}}}return file;
}/*** 复制目录下所有文件到cacheDir目录下*/
private File unpackUrlResource(URL url, String fileName, ClassLoader cl, boolean isDir) {//获取协议String prot = url.getProtocol();switch (prot) {case "file":return unpackFromFileURL(url, fileName, cl);case "jar":return unpackFromJarURL(url, fileName, cl);case "bundle": // Apache Felix, Knopflerfishcase "bundleentry": // Equinoxcase "bundleresource": // Equinoxreturn unpackFromBundleURL(url, isDir);default:throw new IllegalStateException("Invalid url protocol: " + prot);}
}