tomcat 中如何测试 servlet ？

http://localhost:8080/examples/servlet/HelloWorldExample

解决方案 »

  1.   

    需要在相应的web。xml里面加上该servlet的声明
      <servlet>
        <servlet-name>HelloWorldExample</servlet-name>
        <servlet-class>myproject.HelloWorldExample</servlet-class>
      </servlet>
      <servlet-mapping>
        <servlet-name>HelloWorldExample</servlet-name>
        <url-pattern>/HelloWorldExample</url-pattern>
      </servlet-mapping>
      

  2.   

    换成 http://localhost:8080/examples/servlet/HelloWorldExample 真的可以了，
    可是有一点我还不明白，examples/servlet目录下并没有HelloWorldExample.class呀？
    如果我想输入http://localhost:8080/HelloWorldExample就能达到同样的效果，请问我该在server.xml中如何修改？
      

  3.   

    我自己写了个ServiceServlet.class，和以上的HelloWorldExample.class放在了同一个目录下，内容如下：
    public class ServiceServlet extends HttpServlet {
      public ServiceServlet() {
      }
      public void service(HttpServletRequest request,HttpServletResponse response)throws ServletException,
          IOException {
        String name;
        response.setContentType("text/html");
        PrintWriter out = response.getWriter();
        name = request.getParameter("name");
        out.println("Thank you,"+name);
        out.close();
      }
    }又建了一个html文件：
    <html>
    <head>
    <title>Guest Book</title>
    </head>
    <body>
    <form method="post" action="http://localhost:8080/examples/servlet/ServiceServlet">
    Please sing our Guest Book.<br>
    <input type="text" name="name" size="20">
    <input type="submit" value="Save Name">
    </form>
    </body>
    </html>为什么提交了表单后出错，IE中提示信息如下：
      

  4.   

    HTTP Status 500 - --------------------------------------------------------------------------------type Exception reportmessage description The server encountered an internal error () that prevented it from fulfilling this request.exception javax.servlet.ServletException: Cannot allocate servlet instance for path /examples/servlet/ServiceServlet
    at org.apache.catalina.servlets.InvokerServlet.serveRequest(InvokerServlet.java:435)
    at org.apache.catalina.servlets.InvokerServlet.doGet(InvokerServlet.java:180)
    at javax.servlet.http.HttpServlet.service(HttpServlet.java:740)
    at javax.servlet.http.HttpServlet.service(HttpServlet.java:853)
    at org.apache.catalina.core.ApplicationFilterChain.internalDoFilter(ApplicationFilterChain.java:247)
    at org.apache.catalina.core.ApplicationFilterChain.doFilter(ApplicationFilterChain.java:193)
    at filters.ExampleFilter.doFilter(ExampleFilter.java:149)
    at org.apache.catalina.core.ApplicationFilterChain.internalDoFilter(ApplicationFilterChain.java:213)
    at org.apache.catalina.core.ApplicationFilterChain.doFilter(ApplicationFilterChain.java:193)
    at filters.ExampleFilter.doFilter(ExampleFilter.java:149)
    at org.apache.catalina.core.ApplicationFilterChain.internalDoFilter(ApplicationFilterChain.java:213)
    at org.apache.catalina.core.ApplicationFilterChain.doFilter(ApplicationFilterChain.java:193)
    at org.apache.catalina.core.StandardWrapperValve.invoke(StandardWrapperValve.java:256)
    at org.apache.catalina.core.StandardPipeline$StandardPipelineValveContext.invokeNext(StandardPipeline.java:643)
    at org.apache.catalina.core.StandardPipeline.invoke(StandardPipeline.java:480)
    at org.apache.catalina.core.ContainerBase.invoke(ContainerBase.java:995)
    at org.apache.catalina.core.StandardContextValve.invoke(StandardContextValve.java:191)
    at org.apache.catalina.core.StandardPipeline$StandardPipelineValveContext.invokeNext(StandardPipeline.java:643)
    at org.apache.catalina.authenticator.AuthenticatorBase.invoke(AuthenticatorBase.java:494)
    at org.apache.catalina.core.StandardPipeline$StandardPipelineValveContext.invokeNext(StandardPipeline.java:641)
    at org.apache.catalina.core.StandardPipeline.invoke(StandardPipeline.java:480)
    at org.apache.catalina.core.ContainerBase.invoke(ContainerBase.java:995)
    at org.apache.catalina.core.StandardContext.invoke(StandardContext.java:2415)
    at org.apache.catalina.core.StandardHostValve.invoke(StandardHostValve.java:180)
    at org.apache.catalina.core.StandardPipeline$StandardPipelineValveContext.invokeNext(StandardPipeline.java:643)
    at org.apache.catalina.valves.ErrorDispatcherValve.invoke(ErrorDispatcherValve.java:171)
    at org.apache.catalina.core.StandardPipeline$StandardPipelineValveContext.invokeNext(StandardPipeline.java:641)
    at org.apache.catalina.valves.ErrorReportValve.invoke(ErrorReportValve.java:172)
    at org.apache.catalina.core.StandardPipeline$StandardPipelineValveContext.invokeNext(StandardPipeline.java:641)
    at org.apache.catalina.core.StandardPipeline.invoke(StandardPipeline.java:480)
    at org.apache.catalina.core.ContainerBase.invoke(ContainerBase.java:995)
    at org.apache.catalina.core.StandardEngineValve.invoke(StandardEngineValve.java:174)
    at org.apache.catalina.core.StandardPipeline$StandardPipelineValveContext.invokeNext(StandardPipeline.java:643)
    at org.apache.catalina.core.StandardPipeline.invoke(StandardPipeline.java:480)
    at org.apache.catalina.core.ContainerBase.invoke(ContainerBase.java:995)
    at org.apache.coyote.tomcat4.CoyoteAdapter.service(CoyoteAdapter.java:223)
    at org.apache.coyote.http11.Http11Processor.process(Http11Processor.java:594)
    at org.apache.coyote.http11.Http11Protocol$Http11ConnectionHandler.processConnection(Http11Protocol.java:392)
    at org.apache.tomcat.util.net.TcpWorkerThread.runIt(PoolTcpEndpoint.java:565)
    at org.apache.tomcat.util.threads.ThreadPool$ControlRunnable.run(ThreadPool.java:619)
    at java.lang.Thread.run(Thread.java:536)