package exception; public class NetworkException extends CrawlerException { public NetworkException(String message) { super(message); } public NetworkException(String message, Throwable cause) { super(message, cause); } public static NetworkException connectionFailed(String host) { return new NetworkException("网络连接失败,无法访问: " + host, new java.net.ConnectException("Connection refused")); } public static NetworkException unknownHost(String host) { return new NetworkException("无法解析域名: " + host, new java.net.UnknownHostException(host)); } public static NetworkException timeout(String host) { return new NetworkException("请求超时,无法访问: " + host, new java.net.SocketTimeoutException("Read timed out")); } }