servlet调用标准方法出错
import java.io.*;
import javax.servlet.*;
import javax.servlet.http.*;
public class ContextServlet extends HttpServlet{
public void init(ServletConfig config)
throws ServletException{
super.init(config);
}
public void doGet(HttpServletRequest request,
HttpServletResponse response)
throws ServletException,IOException{
doPost(request,response);
}
public void doPost(HttpServletRequest request,
HttpServletResponse response)
throws ServletException,IOException{
ServletContext context = getServletContext();
String un = (String)context.getAttribute("USERNAME");
if (un == null){
un = "HOWE";
//下面这句出问题了
context.setAttribute("USERNAME",un);
}
response.setContentType("text/html");
PrintWriter out = response.getWriter();
out.println("<html>");
out.println("<head><title>Context Servlet</title></head>");
out.println("<body>");
out.println("The current user is:"+un);
out.println("</body></html>");
out.close();
}
}
我用的是oracle 9ias带的apache jserv,将该servlet放在
d:\ora9ias\apache\jserv\servlet下,如果将
context.setAttribute("USERNAME",un);这句屏蔽掉,就可以执行了。
说明最起码象helloworld这种servlet是可以运行的。
但是不知道为什么setAttribute方法就不行呢?
提示错误信息:
[24/03/2004 09:32:33:046 CST] Spy: init
java.lang.NoSuchMethodError
at org.apache.jserv.JServConnection.processRequest(JServConnection.java:512)
at org.apache.jserv.JServConnection.run(JServConnection.java:321)
at java.lang.Thread.run(Thread.java:484)
[24/03/2004 09:53:46:531 CST] ContextServlet: init
[24/03/2004 09:53:46:531 CST] java.lang.NoSuchMethodError
at org.apache.jserv.JServConnection.processRequest(JServConnection.java:512)
at org.apache.jserv.JServConnection.run(JServConnection.java:321)
at java.lang.Thread.run(Thread.java:484)
是NoSuchMethodError!怎么可能呢???