我正在尝试创建一个简单的登录应用程序。我创建了一个登录页面和一个servlet,但它提供了ServletException
这是我的示例代码。
public class Hello extends HttpServlet{
@Override
public void doGet(HttpServletRequest request, HttpServletResponse response) throws ServletException,IOException{
try{
response.setContentType("text/html");
PrintWriter out = response.getWriter();
String username=request.getParameter("username");
String password=request.getParameter("password");
out.println("hello");
if(username.equals("xyz")&&password.equals("password"))
{
HttpSession session=request.getSession();
session.setAttribute("uname",username);
RequestDispatcher rd=request.getRequestDispatcher("/Home.jsp");
rd.forward(request, response);
}
else
{
RequestDispatcher rd=request.getRequestDispatcher("/login.html");
out.println("<h4>Plz provide correct Username or password</h4>");
rd.include(request,response);
}
out.close();
}catch(Exception e){System.out.println(e);}
}
此代码提供以下异常: 我不知道为什么会这样。
javax.servlet.ServletException: Class com.mq.sample.Hello is not a Servlet
org.apache.catalina.valves.ErrorReportValve.invoke(ErrorReportValve.java:102)
org.apache.catalina.connector.CoyoteAdapter.service(CoyoteAdapter.java:298)
org.apache.coyote.http11.Http11Processor.process(Http11Processor.java:857)
org.apache.coyote.http11.Http11Protocol$Http11ConnectionHandler.process(Http11Protocol.java:588)
org.apache.tomcat.util.net.JIoEndpoint$Worker.run(JIoEndpoint.java:489)
java.lang.Thread.run(Unknown Source)
root cause
java.lang.ClassCastException: com.mq.sample.Hello cannot be cast to javax.servlet.Servlet
org.apache.catalina.valves.ErrorReportValve.invoke(ErrorReportValve.java:102)
org.apache.catalina.connector.CoyoteAdapter.service(CoyoteAdapter.java:298)
org.apache.coyote.http11.Http11Processor.process(Http11Processor.java:857)
org.apache.coyote.http11.Http11Protocol$Http11ConnectionHandler.process(Http11Protocol.java:588)
org.apache.tomcat.util.net.JIoEndpoint$Worker.run(JIoEndpoint.java:489)
java.lang.Thread.run(Unknown Source)
提前致谢
答案 0 :(得分:1)
您从Tomcat收到错误,请参阅this link。所以问题是你的类路径中有servlet jar冲突。 从classpath中删除javax.servlet-api.jar并执行此操作。