Eclipse &引用；ClassNotFoundException:org.simpleframework.xml.Serializer“0”；尝试使用简单XML API时

我正在使用简单的XMLAPI对从Android应用程序发送到servlet的XML数据进行序列化和反序列化。 反序列化在android应用程序上运行良好。但是，当在servlet上使用相同的代码时，我会得到以下错误：

SEVERE: Servlet.service() for servlet [servlettest.ServletTest] in context with path [/test] threw exception [Servlet execution threw an exception] with root cause
java.lang.ClassNotFoundException: org.simpleframework.xml.Serializer
    at org.apache.catalina.loader.WebappClassLoader.loadClass(WebappClassLoader.java:1676)
    at org.apache.catalina.loader.WebappClassLoader.loadClass(WebappClassLoader.java:1521)
    at servlettest.ServletTest.doPost(ServletTest.java:104)
    at javax.servlet.http.HttpServlet.service(HttpServlet.java:641)
    at javax.servlet.http.HttpServlet.service(HttpServlet.java:722)
    at org.apache.catalina.core.ApplicationFilterChain.internalDoFilter(ApplicationFilterChain.java:304)
    at org.apache.catalina.core.ApplicationFilterChain.doFilter(ApplicationFilterChain.java:210)
    at org.apache.catalina.core.StandardWrapperValve.invoke(StandardWrapperValve.java:240)
    at org.apache.catalina.core.StandardContextValve.invoke(StandardContextValve.java:164)
    at org.apache.catalina.authenticator.AuthenticatorBase.invoke(AuthenticatorBase.java:462)
    at org.apache.catalina.core.StandardHostValve.invoke(StandardHostValve.java:164)
    at org.apache.catalina.valves.ErrorReportValve.invoke(ErrorReportValve.java:100)
    at org.apache.catalina.valves.AccessLogValve.invoke(AccessLogValve.java:562)
    at org.apache.catalina.core.StandardEngineValve.invoke(StandardEngineValve.java:118)
    at org.apache.catalina.connector.CoyoteAdapter.service(CoyoteAdapter.java:395)
    at org.apache.coyote.http11.Http11Processor.process(Http11Processor.java:250)
    at org.apache.coyote.http11.Http11Protocol$Http11ConnectionHandler.process(Http11Protocol.java:188)
    at org.apache.coyote.http11.Http11Protocol$Http11ConnectionHandler.process(Http11Protocol.java:166)
    at org.apache.tomcat.util.net.JIoEndpoint$SocketProcessor.run(JIoEndpoint.java:302)
    at java.util.concurrent.ThreadPoolExecutor.runWorker(ThreadPoolExecutor.java:1110)
    at java.util.concurrent.ThreadPoolExecutor$Worker.run(ThreadPoolExecutor.java:603)
    at java.lang.Thread.run(Thread.java:722)

突出显示的是

java.lang.ClassNotFoundException:org.simpleframework.xml.Serializer

我已确保jar文件已导入Eclipse中。它已在“属性”窗口的“订单和导出”选项卡下选中标记

以下代码在Android上运行良好，但在servlet上失败：

Serializer serializer = new Persister();
            File source = new File("/home/kk/workspace/testfile.xml");

            Reg_info_xml parse_xml = serializer.read(Reg_info_xml.class, source);
            String name = parse_xml.getUser_name();
            System.out.print(name);

---

类不在服务器类路径中，因此请将jar放在项目的WEB-INF/lib文件夹中。我确实把它放在那个文件夹里了，但我还是得到了同样的错误。我把它作为外部罐子导入，对吗？明白了！必须在Eclipse中刷新/lib目录才能让它检测jar文件。谢谢：）