如何登录Undertow嵌入式服务器中的文件？

<dependency>
    <groupId>io.undertow</groupId>
    <artifactId>undertow-core</artifactId>
    <version>2.2.12.Final</version>
</dependency>

Undertow server = Undertow.builder()
        .addHttpListener(8080, "localhost")
        .build();

HttpHandler handler = new HttpHandler() {
    @Override
    public void handleRequest(HttpServerExchange exchange) throws Exception {
        // 在这里处理请求
    }
};

server.setHandler(handler);

server.start();

Path filePath = Paths.get("path/to/file.txt");
byte[] fileContent = Files.readAllBytes(filePath);
exchange.getResponseSender().send(fileContent);