java发生了什么Http状态500实例化servlet类时出错

Question

例外情况

javax.servlet.ServletException: Error instantiating servlet class SAA.Servlet.Addrest
    org.apache.catalina.valves.ErrorReportValve.invoke(ErrorReportValve.java:99)
    org.apache.catalina.valves.AccessLogValve.invoke(AccessLogValve.java:936)
    org.apache.catalina.connector.CoyoteAdapter.service(CoyoteAdapter.java:407)
    org.apache.coyote.http11.AbstractHttp11Processor.process(AbstractHttp11Processor.java:1004)
    org.apache.coyote.AbstractProtocol$AbstractConnectionHandler.process(AbstractProtocol.java:589)
    org.apache.tomcat.util.net.JIoEndpoint$SocketProcessor.run(JIoEndpoint.java:312)
    java.util.concurrent.ThreadPoolExecutor.runWorker(Unknown Source)
    java.util.concurrent.ThreadPoolExecutor$Worker.run(Unknown Source)
    java.lang.Thread.run(Unknown Source)


root cause 

java.lang.ClassNotFoundException: SAA.Servlet.Addrest
    org.apache.catalina.loader.WebappClassLoader.loadClass(WebappClassLoader.java:1713)
    org.apache.catalina.loader.WebappClassLoader.loadClass(WebappClassLoader.java:1558)
    org.apache.catalina.valves.ErrorReportValve.invoke(ErrorReportValve.java:99)
    org.apache.catalina.valves.AccessLogValve.invoke(AccessLogValve.java:936)
    org.apache.catalina.connector.CoyoteAdapter.service(CoyoteAdapter.java:407)
    org.apache.coyote.http11.AbstractHttp11Processor.process(AbstractHttp11Processor.java:1004)
    org.apache.coyote.AbstractProtocol$AbstractConnectionHandler.process(AbstractProtocol.java:589)
    org.apache.tomcat.util.net.JIoEndpoint$SocketProcessor.run(JIoEndpoint.java:312)
    java.util.concurrent.ThreadPoolExecutor.runWorker(Unknown Source)
    java.util.concurrent.ThreadPoolExecutor$Worker.run(Unknown Source)
    java.lang.Thread.run(Unknown Source)

Answer 1

在类路径中找不到SAA.Servlet.Addrest

java.lang.ClassNotFoundException: SAA.Servlet.Addrest

• 确保完全限定类名正确
• 确保类位于具有完全限定包空间的类路径中