有异常：

java.lang.ClassNotFoundException: org.xmlpull.v1.XmlPullParserException

at org.apache.catalina.loader.WebappClassLoader.loadClass(WebappClassLoader.java:1358)

at org.apache.catalina.loader.WebappClassLoader.loadClass(WebappClassLoader.java:1204)

at com.thoughtworks.xstream.XStream.<init>(XStream.java:350)

at util.MessageUtil.textMessagetoXml(MessageUtil.java:38)

at servlet.Weixin.doPost(Weixin.java:74)

at javax.servlet.http.HttpServlet.service(HttpServlet.java:710)

at javax.servlet.http.HttpServlet.service(HttpServlet.java:803)

at org.apache.catalina.core.ApplicationFilterChain.internalDoFilter(ApplicationFilterChain.java:290)

at org.apache.catalina.core.ApplicationFilterChain.doFilter(ApplicationFilterChain.java:206)

at org.apache.catalina.core.StandardWrapperValve.invoke(StandardWrapperValve.java:230)

at org.apache.catalina.core.StandardContextValve.invoke(StandardContextValve.java:175)

at org.apache.catalina.core.StandardHostValve.invoke(StandardHostValve.java:128)

at org.apache.catalina.valves.ErrorReportValve.invoke(ErrorReportValve.java:104)

at org.apache.catalina.core.StandardEngineValve.invoke(StandardEngineValve.java:109)

at org.apache.catalina.connector.CoyoteAdapter.service(CoyoteAdapter.java:261)

at org.apache.coyote.http11.Http11Processor.process(Http11Processor.java:844)

at org.apache.coyote.http11.Http11Protocol$Http11ConnectionHandler.process(Http11Protocol.java:581)

at org.apache.tomcat.util.net.JIoEndpoint$Worker.run(JIoEndpoint.java:447)

at java.lang.Thread.run(Thread.java:744)