我正在使用 Xerces 验证 XML 文件，并在我的类路径中本地保存所有模式文件（使用 XML 目录）。
Validator validator = schema.newValidator();
validator.setResourceResolver(CatalogResourceResolver.getInstance());
validator.validate(getSource(true));
（getSource(boolean) 获取 SAXSource）
通常，系统 ID 是某个 URI 或 URL。
一些验证需要很长时间，最近我得到了：
java.net.ConnectException: Connection timed out: connect
at java.net.PlainSocketImpl.socketConnect(Native Method)
at java.net.PlainSocketImpl.doConnect(PlainSocketImpl.java:333)
at java.net.PlainSocketImpl.connectToAddress(PlainSocketImpl.java:195)
at java.net.PlainSocketImpl.connect(PlainSocketImpl.java:182)
at java.net.SocksSocketImpl.connect(SocksSocketImpl.java:366)
at java.net.Socket.connect(Socket.java:529)
at java.net.Socket.connect(Socket.java:478)
at sun.net.NetworkClient.doConnect(NetworkClient.java:163)
at sun.net.NetworkClient.openServer(NetworkClient.java:118)
at sun.net.ftp.FtpClient.openServer(FtpClient.java:488)
at sun.net.ftp.FtpClient.openServer(FtpClient.java:475)
at sun.net.www.protocol.ftp.FtpURLConnection.connect(FtpURLConnection.java:270)
at sun.net.www.protocol.ftp.FtpURLConnection.getInputStream(FtpURLConnection.java:352)
at org.apache.xerces.impl.XMLEntityManager.setupCurrentEntity(Unknown Source)
at org.apache.xerces.impl.XMLEntityManager.startEntity(Unknown Source)
at org.apache.xerces.impl.XMLEntityManager.startDTDEntity(Unknown Source)
at org.apache.xerces.impl.XMLDTDScannerImpl.setInputSource(Unknown Source)
at org.apache.xerces.impl.XMLDocumentScannerImpl$DTDDispatcher.dispatch(Unknown Source)
at org.apache.xerces.impl.XMLDocumentFragmentScannerImpl.scanDocument(Unknown Source)
at org.apache.xerces.parsers.XML11Configuration.parse(Unknown Source)
at org.apache.xerces.parsers.XML11Configuration.parse(Unknown Source)
at org.apache.xerces.parsers.XMLParser.parse(Unknown Source)
at org.apache.xerces.parsers.AbstractSAXParser.parse(Unknown Source)
at org.apache.xerces.jaxp.SAXParserImpl$JAXPSAXParser.parse(Unknown Source)
at org.apache.xerces.jaxp.validation.ValidatorHandlerImpl.validate(Unknown Source)
at org.apache.xerces.jaxp.validation.ValidatorImpl.validate(Unknown Source)
at javax.xml.validation.Validator.validate(Validator.java:127)
很明显，Xerces 正在尝试下载该文件。
我怎么能阻止它？