selenium自动化遇见Cannot find class in classpath问题

今天遇见了Cannot find class in classpath的问题，

org.testng.TestNGException:
Cannot find class in classpath: com.sectest.testcases.login.LoginBmsCase
at org.testng.xml.XmlClass.loadClass(XmlClass.java:81)
at org.testng.xml.XmlClass.init(XmlClass.java:73)
at org.testng.xml.XmlClass.<init>(XmlClass.java:59)
at org.testng.xml.TestNGContentHandler.startElement(TestNGContentHandler.java:539)
at com.sun.org.apache.xerces.internal.parsers.AbstractSAXParser.startElement(Unknown Source)
at com.sun.org.apache.xerces.internal.impl.dtd.XMLDTDValidator.startElement(Unknown Source)
at com.sun.org.apache.xerces.internal.impl.XMLDocumentFragmentScannerImpl.scanStartElement(Unknown Source)
at com.sun.org.apache.xerces.internal.impl.XMLDocumentFragmentScannerImpl$FragmentContentDriver.next(Unknown Source)
at com.sun.org.apache.xerces.internal.impl.XMLDocumentScannerImpl.next(Unknown Source)
at com.sun.org.apache.xerces.internal.impl.XMLDocumentFragmentScannerImpl.scanDocument(Unknown Source)
at com.sun.org.apache.xerces.internal.parsers.XML11Configuration.parse(Unknown Source)
at com.sun.org.apache.xerces.internal.parsers.XML11Configuration.parse(Unknown Source)
at com.sun.org.apache.xerces.internal.parsers.XMLParser.parse(Unknown Source)
at com.sun.org.apache.xerces.internal.parsers.AbstractSAXParser.parse(Unknown Source)
at com.sun.org.apache.xerces.internal.jaxp.SAXParserImpl$JAXPSAXParser.parse(Unknown Source)
at com.sun.org.apache.xerces.internal.jaxp.SAXParserImpl.parse(Unknown Source)
at javax.xml.parsers.SAXParser.parse(Unknown Source)
at org.testng.xml.SuiteXmlParser.parse(SuiteXmlParser.java:17)
at org.testng.xml.SuiteXmlParser.parse(SuiteXmlParser.java:10)
at org.testng.xml.Parser.parse(Parser.java:172)
at org.testng.TestNG.initializeSuitesAndJarFile(TestNG.java:310)
at org.testng.remote.AbstractRemoteTestNG.run(AbstractRemoteTestNG.java:103)
at org.testng.remote.RemoteTestNG.initAndRun(RemoteTestNG.java:152)
at org.testng.remote.RemoteTestNG.main(RemoteTestNG.java:57)

在网上查的资料显示，有可能是xml的问题，但是这个xml我用了一个多月了 ，没有出现这样的问题的。好吧，重建path，也还是不行。最后没办法 找到之前备份好的文件，把里面的.classxpath 给替换了 ，然后他就神奇的可以使用了。。。