javaによる複数の特定ディレクトリ以下の静的リソースを返すHttpサーバー（やっつけ実装)

StaticResourceHttpServer

package server;

import java.io.File;
import java.io.IOException;
import java.io.OutputStream;
import java.net.InetSocketAddress;
import java.nio.file.FileSystem;
import java.nio.file.FileSystems;
import java.nio.file.FileVisitResult;
import java.nio.file.Files;
import java.nio.file.Path;
import java.nio.file.SimpleFileVisitor;
import java.nio.file.attribute.BasicFileAttributes;
import java.util.HashMap;
import java.util.Map;

import com.sun.net.httpserver.HttpExchange;
import com.sun.net.httpserver.HttpHandler;
import com.sun.net.httpserver.HttpServer;

/**
 * HttpServer of static resources.
 * 
 * configure paths and port in main method.
 * paths's key is context. It maps http://localhost:8080/this
 * paths's values is file system path.
 * http://localhost:8080/this/xxx is maps in  file system.
 *
 */
public class StaticResourceHttpServer {

	public static void main(String[] args) throws IOException {

		final Map<String, String> paths = new HashMap<String, String>(){{
				put("example1", "WebContent/example");
				put("example2", "c:/temp/example2");
		}};
		int port = 8080;
		new StaticResourceHttpServer().runSeaver(paths, port);
	}

	private Map<String, String> paths;

	public void runSeaver(Map<String, String> staticPaths, int port) throws IOException {
		this.paths = staticPaths;
		

		final HttpServer server = HttpServer.create(
				new InetSocketAddress(port), 0);
		
		for (Map.Entry<String, String> entry : paths.entrySet()) {
			final String context = entry.getKey();
			String fsPath = entry.getValue();
			

			FileSystem fs = FileSystems.getDefault();
			final Path root = fs.getPath(fsPath);
			Files.walkFileTree(root,
					new SimpleFileVisitor<Path>() {
						@Override
						public FileVisitResult visitFile(Path file,
								BasicFileAttributes attrs) throws IOException {
							
							Path p = root.relativize(file);
							
							server.createContext(toUrl(context, p.toString()),
									fileHander);

							return super.visitFile(file, attrs);
						}
					});
		}
		
		server.setExecutor(null);
		server.start();
	}

	private String toUrl(String context, String filePath) {
		String res = "/" + context + "/" + filePath.replace('\\', '/');
		System.out.println(res);
		return res;

	}

	private final HttpHandler fileHander = new HttpHandler() {

		private Map<String, String> ct = new HashMap<String, String>() {
			{
				put("html", "text/html;charset=utf-8");
				put("xml", "text/xml");
				put("css", "text/css;charset=utf-8");
				put("js", "text/javascript;charset=utf-8");
				put("json", "application/json");
			}
		};

		@Override
		public void handle(HttpExchange ex) throws IOException {

			String path = ex.getRequestURI().getPath();
			
			String context = path.substring(1, path.indexOf("/", 1));
			String realPath = paths.get(context) + path.substring(path.indexOf("/", 1));
			System.out.println(realPath);

			String suffix = realPath.substring(realPath.lastIndexOf(".") + 1);
			if (ct.containsKey(suffix)) {

				ex.getResponseHeaders().add("Content-Type", ct.get(suffix));
			}
			byte[] res = read(realPath);
			ex.sendResponseHeaders(200, res.length);
			OutputStream os = ex.getResponseBody();
			os.write(res);
			os.close();
			ex.close();
		}
	};

	private static byte[] read(String path) throws IOException {
		return Files.readAllBytes(new File(path).toPath());
	}

}