在使用servlet调用生成二维码的类时会抛出异常

java.lang.ClassNotFoundException: com.swetake.util.Qrcode
 at org.apache.catalina.loader.WebappClassLoaderBase.loadClass(WebappClassLoaderBase.java:1305)
 at org.apache.catalina.loader.WebappClassLoaderBase.loadClass(WebappClassLoaderBase.java:1139)
 at com.test.qrcode.CreateQRCode.CreateQRCode(CreateQRCode.java:16)
 at com.test.servlet.CreateCodeServlet.doGet(CreateCodeServlet.java:39)
 at javax.servlet.http.HttpServlet.service(HttpServlet.java:622)
 at javax.servlet.http.HttpServlet.service(HttpServlet.java:729)
 at org.apache.catalina.core.ApplicationFilterChain.internalDoFilter(ApplicationFilterChain.java:292)
 at org.apache.catalina.core.ApplicationFilterChain.doFilter(ApplicationFilterChain.java:207)
 at org.apache.tomcat.websocket.server.WsFilter.doFilter(WsFilter.java:52)
 at org.apache.catalina.core.ApplicationFilterChain.internalDoFilter(ApplicationFilterChain.java:240)
 at org.apache.catalina.core.ApplicationFilterChain.doFilter(ApplicationFilterChain.java:207)
 at org.apache.catalina.core.StandardWrapperValve.invoke(StandardWrapperValve.java:212)
 at org.apache.catalina.core.StandardContextValve.invoke(StandardContextValve.java:106)
 at org.apache.catalina.authenticator.AuthenticatorBase.invoke(AuthenticatorBase.java:502)
 at org.apache.catalina.core.StandardHostValve.invoke(StandardHostValve.java:141)
 at org.apache.catalina.valves.ErrorReportValve.invoke(ErrorReportValve.java:79)
 at org.apache.catalina.valves.AbstractAccessLogValve.invoke(AbstractAccessLogValve.java:616)
 at org.apache.catalina.core.StandardEngineValve.invoke(StandardEngineValve.java:88)
 at org.apache.catalina.connector.CoyoteAdapter.service(CoyoteAdapter.java:522)
 at org.apache.coyote.http11.AbstractHttp11Processor.process(AbstractHttp11Processor.java:1095)
 at org.apache.coyote.AbstractProtocol$AbstractConnectionHandler.process(AbstractProtocol.java:672)
 at org.apache.tomcat.util.net.AprEndpoint$SocketProcessor.doRun(AprEndpoint.java:2500)
 at org.apache.tomcat.util.net.AprEndpoint$SocketProcessor.run(AprEndpoint.java:2489)
 at java.util.concurrent.ThreadPoolExecutor.runWorker(ThreadPoolExecutor.java:1142)
 at java.util.concurrent.ThreadPoolExecutor$Worker.run(ThreadPoolExecutor.java:617)
 at org.apache.tomcat.util.threads.TaskThread$WrappingRunnable.run(TaskThread.java:61)
 at java.lang.Thread.run(Thread.java:745)