的Servlet抛出异常有关部署在Tomcat

Question

我开发下方计数器的应用是我的应用程序的结构..

第一监听器类

package com.saral; 

import javax.servlet.*; 

public class AppListener implements ServletContextListener 
{ 
ServletContext ctx; 
public void contextInitialized(ServletContextEvent e) 
{ 
ctx=e.getServletContext(); 
ctx.setAttribute("hitCount",new Integer(0)); 
} 
public void contextDestroyed(ServletContextEvent e) 
{} 
} 

然后过滤器类..

package com.saral; 

import javax.servlet.*; 

public class CounterFilter implements Filter 
{ 
ServletContext ctx; 
public void init(FilterConfig config){ 
ctx=config.getServletContext(); 
} 
public void destroy(){} 
public void doFilter(ServletRequest request,ServletResponse response,FilterChain chain) 
{ 
try 
{ 
Integer ct=(Integer)ctx.getAttribute("hitCount"); 
int c=ct.intValue(); 
c++; 
ctx.setAttribute("hitCount",new Integer(c)); 
chain.doFilter(request,response); 
}catch(Exception e) 
{ 
System.out.println(e); 
} 
} 
} 

后面跟着登录servlet ..

package com.saral; 

import java.io.*; 
import javax.servlet.*; 
import javax.servlet.http.*; 
import java.sql.*; 
public class LoginServlet extends HttpServlet 
{ 
public void doGet(HttpServletRequest request,HttpServletResponse response) 
{ 
try{ 
String name=request.getParameter("txtName"); 
String pass=request.getParameter("txtPass"); 
Class.forName("oracle.jdbc.driver.OracleDriver"); 
Connection con=DriverManager.getConnection("jdbc:oracle:thin:@localhost:1521:xe"); 
PreparedStatement stmt=con.prepareStatement("select * from logininfo where username=? and password=?"); 
stmt.setString(1,name); 
stmt.setString(2,pass); 
ResultSet rset=stmt.executeQuery(); 
response.setContentType("text/html"); 
PrintWriter out=response.getWriter(); 
if (rset.next()) 
{ 
request.getSession().setAttribute("username",name); 
RequestDispatcher rd=request.getRequestDispatcher("aa"); 
rd.forward(request,response); 
} 
else 
{ 
System.out.println("in else"); 
out.println("<b>Invalid user name or password.</b><br>"); 
RequestDispatcher rd=request.getRequestDispatcher("home.html"); 
rd.include(request,response); 
} 
out.close(); 
con .close(); 
}catch(Exception e) 
{ 
System.out.println(e); 
} 
} 
} 

其次servlet2 ..

package com.saral; 

import java.io.*; 
import javax.servlet.*; 
import javax.servlet.http.*; 

public class ServletTwo extends HttpServlet 
{ 
public void doGet(HttpServletRequest request,HttpServletResponse response) throws ServletException,IOException 
{ 
HttpSession ses=request.getSession(); 
String name=(String)ses.getAttribute("username"); 
response.setContentType("text/html"); 
PrintWriter out=response.getWriter(); 
out.println("welcome,"+name); 
out.println("<br> <a href=viewServlet>View Hit Count</a>"); 
out.close(); 
} 
} 

最后查看的servlet ..

package com.saral; 

import javax.servlet.*; 
import javax.servlet.http.*; 
import java.io.*; 

public class ViewServlet extends HttpServlet 
{ 
public void doGet(HttpServletRequest request,HttpServletResponse response) throws ServletException,IOException 
{ 
ServletContext ctx=getServletContext(); 
int c=((Integer)ctx.getAttribute("hitCount")).intValue(); 
response.setContentType("text/html"); 
PrintWriter out=response.getWriter(); 
out.println("hit count is:"+c); 
out.close(); 
} 
} 

我写这样的web.xml文件..

<web-app> 

<listener> 
<listener-class>AppListener</listener-class> 
</listener> 

<filter> 
<filter-name>counter</filter-name> 
<filter-class>com.saral.CounterFilter</filter-class> 
</filter> 
<filter-mapping> 
<filter-name>counter</filter-name> 
<url-pattern>*</url-pattern> 
</filter-mapping> 
<servlet> 
<servlet-name>hello</servlet-name> 
<servlet-class>com.saral.LoginServlet</servlet-class> 
<init-param> 
<param-name>driverClass</param-name> 
<param-value>oracle.jdbc.driver.OracleDriver</param-value> 
</init-param> 
<init-param> 
<param-name>connectionString</param-name> 
<param-value>jdbc:oracle:thin:@localhost:1521:xe</param-value> 
</init-param> 
<init-param> 
<param-name>userName</param-name> 
<param-value>saral</param-value> 
</init-param> 
<init-param> 
<param-name>password</param-name> 
<param-value>saral</param-value> 
</init-param> 

</servlet> 
<servlet-mapping> 
<servlet-name>hello</servlet-name> 
<url-pattern>/loginServlet</url-pattern> 
</servlet-mapping> 
<servlet> 
<servlet-name>two</servlet-name> 
<servlet-class>com.saral.ServletTwo</servlet-class> 
</servlet> 
<servlet-mapping> 
<servlet-name>two</servlet-name> 
<url-pattern>/aa</url-pattern> 
</servlet-mapping> 
<servlet> 
<servlet-name>three</servlet-name> 
<servlet-class>com.saral.ViewServlet</servlet-class> 
</servlet> 
<servlet-mapping> 
<servlet-name>three</servlet-name> 
<url-pattern>/viewServlet</url-pattern> 
</servlet-mapping> 
<welcome-file-list> 
<welcome-file>home.html</welcome-file> 
</welcome-file-list> 
</web-app> 

和我的主html是..

<html> 
<head> 
<title> A Simple web Application</title> 
</head> 
<body> 
<form method="get" action="loginServlet"> 
Name<input type="text" name="txtName"/> 
Password<input type="password" name="txtPass"/> 
<input type="submit" value="Login"/> 
</form> 
</body> 
</html> 

但在部署在Tomcat 7这个应用程序，它抛出的错误..

NFO: Starting Servlet Engine: Apache Tomcat/7.0.27 
15 Jul, 2012 12:05:14 PM org.apache.catalina.core.StandardContext listenerStart 
SEVERE: Error configuring application listener of class AppListener 
java.lang.ClassNotFoundException: AppListener 
    at org.apache.catalina.loader.WebappClassLoader.loadClass(WebappClassLoader.java:1711) 
    at org.apache.catalina.loader.WebappClassLoader.loadClass(WebappClassLoader.java:1556) 
    at org.apache.catalina.core.DefaultInstanceManager.loadClass(DefaultInstanceManager.java:525) 
    at org.apache.catalina.core.DefaultInstanceManager.loadClassMaybePrivileged(DefaultInstanceManager.java:507) 
    at org.apache.catalina.core.DefaultInstanceManager.newInstance(DefaultInstanceManager.java:124) 
    at org.apache.catalina.core.StandardContext.listenerStart(StandardContext.java:4715) 
    at org.apache.catalina.core.StandardContext.startInternal(StandardContext.java:5273) 
    at org.apache.catalina.util.LifecycleBase.start(LifecycleBase.java:150) 
    at org.apache.catalina.core.ContainerBase$StartChild.call(ContainerBase.java:1566) 
    at org.apache.catalina.core.ContainerBase$StartChild.call(ContainerBase.java:1556) 
    at java.util.concurrent.FutureTask$Sync.innerRun(Unknown Source) 
    at java.util.concurrent.FutureTask.run(Unknown Source) 
    at java.util.concurrent.ThreadPoolExecutor$Worker.runTask(Unknown Source) 
    at java.util.concurrent.ThreadPoolExecutor$Worker.run(Unknown Source) 
    at java.lang.Thread.run(Unknown Source) 
15 Jul, 2012 12:05:14 PM org.apache.catalina.core.StandardContext listenerStart 
SEVERE: Skipped installing application listeners due to previous error(s) 
15 Jul, 2012 12:05:14 PM org.apache.catalina.core.StandardContext startInternal 
SEVERE: Error listenerStart 
15 Jul, 2012 12:05:14 PM org.apache.catalina.core.StandardContext startInternal 
SEVERE: Context [/Counter] startup failed due to previous errors 

请告知什么是错在完成申请

这个变化在web.xml中建议

<listener> 
    <listener-class>com.saral.AppListener</listener-class> 
</listener> 

但仍然出现错误..

SEVERE: Error configuring application listener of class com.saral.AppListener 
java.lang.ClassNotFoundException: com.saral.AppListener 
    at org.apache.catalina.loader.WebappClassLoader.loadClass(WebappClassLoader.java:1711) 
    at org.apache.catalina.loader.WebappClassLoader.loadClass(WebappClassLoader.java:1556) 
    at org.apache.catalina.core.DefaultInstanceManager.loadClass(DefaultInstanceManager.java:525) 
    at org.apache.catalina.core.DefaultInstanceManager.loadClassMaybePrivileged(DefaultInstanceManager.java:507) 
    at org.apache.catalina.core.DefaultInstanceManager.newInstance(DefaultInstanceManager.java:124) 
    at org.apache.catalina.core.StandardContext.listenerStart(StandardContext.java:4715) 
    at org.apache.catalina.core.StandardContext.startInternal(StandardContext.java:5273) 
    at org.apache.catalina.util.LifecycleBase.start(LifecycleBase.java:150) 
    at org.apache.catalina.core.ContainerBase$StartChild.call(ContainerBase.java:1566) 
    at org.apache.catalina.core.ContainerBase$StartChild.call(ContainerBase.java:1556) 
    at java.util.concurrent.FutureTask$Sync.innerRun(Unknown Source) 
    at java.util.concurrent.FutureTask.run(Unknown Source) 
    at java.util.concurrent.ThreadPoolExecutor$Worker.runTask(Unknown Source) 
    at java.util.concurrent.ThreadPoolExecutor$Worker.run(Unknown Source) 
    at java.lang.Thread.run(Unknown Source) 
15 Jul, 2012 12:21:13 PM org.apache.catalina.core.StandardContext listenerStart 
SEVERE: Skipped installing application listeners due to previous error(s) 

请注意Ë

Answer 1

在你的web.xml中，你有听众此配置

<listener> 
    <listener-class>AppListener</listener-class> 
</listener> 

类AppListener无法找到，你必须设置的全名（包括包名）：

<listener> 
    <listener-class>com.saral.AppListener</listener-class> 
</listener>