Jdk 1.6换成1.5之后HttpServlet提示编译不正确，类型不能得到解决

2011-12-29 14:25:16 org.apache.catalina.core.AprLifecycleListener lifecycleEvent
信息: The Apache Tomcat Native library which allows optimal performance in production environments was not found on the java.library.path: I:\Program Files\Java\jdk1.5.0\bin;.;I:\WINDOWS\system32;I:\WINDOWS;I:\Program Files\Java\jre6\bin\client;I:\Program Files\Java\jre6\bin;H:\app\Administrator\product\11.2.0\dbhome_1\bin;I:\WINDOWS\system32;I:\WINDOWS;I:\WINDOWS\System32\Wbem;I:\Program Files\TortoiseSVN\bin;I:\Program Files\Java\jdk1.5.0\bin
2011-12-29 14:25:17 org.apache.coyote.http11.Http11BaseProtocol init
信息: Initializing Coyote HTTP/1.1 on http-8080
2011-12-29 14:25:17 org.apache.catalina.startup.Catalina load
信息: Initialization processed in 2437 ms
2011-12-29 14:25:17 org.apache.catalina.core.StandardService start
信息: Starting service Catalina
2011-12-29 14:25:17 org.apache.catalina.core.StandardEngine start
信息: Starting Servlet Engine: Apache Tomcat/5.5.27
2011-12-29 14:25:17 org.apache.catalina.core.StandardHost start
信息: XML validation disabled
2011-12-29 14:25:18 org.apache.coyote.http11.Http11BaseProtocol start
信息: Starting Coyote HTTP/1.1 on http-8080
2011-12-29 14:25:18 org.apache.jk.common.ChannelSocket init
信息: JK: ajp13 listening on /0.0.0.0:8009
2011-12-29 14:25:18 org.apache.jk.server.JkMain start
信息: Jk running ID=0 time=0/16  config=null
2011-12-29 14:25:18 org.apache.catalina.storeconfig.StoreLoader load
信息: Find registry server-registry.xml at classpath resource
2011-12-29 14:25:19 org.apache.catalina.startup.Catalina start
信息: Server startup in 1657 ms
2011-12-29 14:25:44 org.apache.catalina.core.ApplicationContext log
信息: Marking servlet GetServlet as unavailable
2011-12-29 14:25:44 org.apache.catalina.core.StandardWrapperValve invoke
严重: Allocate exception for servlet GetServlet
java.lang.Error: Unresolved compilation problems: 
HttpServlet cannot be resolved to a type
HttpServletRequest cannot be resolved to a type
HttpServletResponse cannot be resolved to a type
ServletException cannot be resolved to a type at com.etoak.servlet.GetServlet.<init>(GetServlet.java:15)
at sun.reflect.NativeConstructorAccessorImpl.newInstance0(Native Method)
at sun.reflect.NativeConstructorAccessorImpl.newInstance(NativeConstructorAccessorImpl.java:39)
at sun.reflect.DelegatingConstructorAccessorImpl.newInstance(DelegatingConstructorAccessorImpl.java:27)
at java.lang.reflect.Constructor.newInstance(Constructor.java:494)
at java.lang.Class.newInstance0(Class.java:350)
at java.lang.Class.newInstance(Class.java:303)
at org.apache.catalina.core.StandardWrapper.loadServlet(StandardWrapper.java:1089)
at org.apache.catalina.core.StandardWrapper.allocate(StandardWrapper.java:791)
at org.apache.catalina.core.StandardWrapperValve.invoke(StandardWrapperValve.java:127)
at org.apache.catalina.core.StandardContextValve.invoke(StandardContextValve.java:172)
at org.apache.catalina.core.StandardHostValve.invoke(StandardHostValve.java:127)
at org.apache.catalina.valves.ErrorReportValve.invoke(ErrorReportValve.java:117)
at org.apache.catalina.core.StandardEngineValve.invoke(StandardEngineValve.java:108)
at org.apache.catalina.connector.CoyoteAdapter.service(CoyoteAdapter.java:174)
at org.apache.coyote.http11.Http11Processor.process(Http11Processor.java:875)
at org.apache.coyote.http11.Http11BaseProtocol$Http11ConnectionHandler.processConnection(Http11BaseProtocol.java:665)
at org.apache.tomcat.util.net.PoolTcpEndpoint.processSocket(PoolTcpEndpoint.java:528)
at org.apache.tomcat.util.net.LeaderFollowerWorkerThread.runIt(LeaderFollowerWorkerThread.java:81)
at org.apache.tomcat.util.threads.ThreadPool$ControlRunnable.run(ThreadPool.java:689)
at java.lang.Thread.run(Thread.java:595)提示这一行报错
public class GetServlet extends HttpServlet {//这里提示我类型不能得到解决 public void service(HttpServletRequest request, HttpServletResponse response)
throws ServletException, IOException {