import io.undertow.Version; //导入依赖的package包/类
private static SetHeadersHandler headersHandler(HttpHandler servletInitialHandler, Config cfg) {
    Map<HttpString, String> headers = new HashMap<>();
    headers.put(HttpString.tryFromString(HEADER_SERVER), cfg.getString(KEY_HEADER_SERVER));
    if (!Environment.isProd()) {
        headers.put(HttpString.tryFromString(HEADER_X_POWERED_BY), Version.getFullVersionString());
    }
    return Boolean.getBoolean(SYS_PROP_ENABLE_REQ_BUFF) ?
            new SetHeadersHandler(reqBufferingHandler(servletInitialHandler, cfg), headers) :
            new SetHeadersHandler(servletInitialHandler, headers);
}
 

import io.undertow.Version; //导入依赖的package包/类
@Override
protected void injectEnvironmentInfoIntoBanner(final Formatter formatter, final Environment environment, final Class<?> sourceClass) {
    formatter.format("Undertow Version: %s%n", Version.getFullVersionString());
    formatter.format("%s%n", LINE_SEPARATOR);
}
 

import io.undertow.Version; //导入依赖的package包/类
@Override
public String getServerInfo() {
    return deploymentInfo.getServerName() + " - " + Version.getVersionString();
}