新手刚开始学习JSP与servlet，不知道为什么总是报这个异常
javax.servlet.ServletException: Error instantiating servlet class com.soft.whdx.servlet.LoginSerlvet
下面是详细错误报告：
type Exception report
message Error instantiating servlet class com.soft.whdx.servlet.LoginSerlvet
description The server encountered an internal error that prevented it from fulfilling this request.
exception
javax.servlet.ServletException: Error instantiating servlet class com.soft.whdx.servlet.LoginSerlvet
org.apache.catalina.authenticator.AuthenticatorBase.invoke(AuthenticatorBase.java:501)
org.apache.catalina.valves.ErrorReportValve.invoke(ErrorReportValve.java:98)
org.apache.catalina.valves.AccessLogValve.invoke(AccessLogValve.java:950)
org.apache.catalina.connector.CoyoteAdapter.service(CoyoteAdapter.java:408)
org.apache.coyote.http11.AbstractHttp11Processor.process(AbstractHttp11Processor.java:1040)
org.apache.coyote.AbstractProtocol$AbstractConnectionHandler.process(AbstractProtocol.java:607)
org.apache.tomcat.util.net.AprEndpoint$SocketProcessor.doRun(AprEndpoint.java:2441)
org.apache.tomcat.util.net.AprEndpoint$SocketProcessor.run(AprEndpoint.java:2430)
java.util.concurrent.ThreadPoolExecutor$Worker.runTask(ThreadPoolExecutor.java:886)
java.util.concurrent.ThreadPoolExecutor$Worker.run(ThreadPoolExecutor.java:908)
java.lang.Thread.run(Thread.java:619)
root cause
java.lang.ClassNotFoundException: com.soft.whdx.servlet.LoginSerlvet
org.apache.catalina.loader.WebappClassLoader.loadClass(WebappClassLoader.java:1720)
org.apache.catalina.loader.WebappClassLoader.loadClass(WebappClassLoader.java:1571)
org.apache.catalina.authenticator.AuthenticatorBase.invoke(AuthenticatorBase.java:501)
org.apache.catalina.valves.ErrorReportValve.invoke(ErrorReportValve.java:98)
org.apache.catalina.valves.AccessLogValve.invoke(AccessLogValve.java:950)
org.apache.catalina.connector.CoyoteAdapter.service(CoyoteAdapter.java:408)
org.apache.coyote.http11.AbstractHttp11Processor.process(AbstractHttp11Processor.java:1040)
org.apache.coyote.AbstractProtocol$AbstractConnectionHandler.process(AbstractProtocol.java:607)
org.apache.tomcat.util.net.AprEndpoint$SocketProcessor.doRun(AprEndpoint.java:2441)
org.apache.tomcat.util.net.AprEndpoint$SocketProcessor.run(AprEndpoint.java:2430)
java.util.concurrent.ThreadPoolExecutor$Worker.runTask(ThreadPoolExecutor.java:886)
java.util.concurrent.ThreadPoolExecutor$Worker.run(ThreadPoolExecutor.java:908)
java.lang.Thread.run(Thread.java:619)
note The full stack trace of the root cause is available in the Apache Tomcat/7.0.53 logs.
其中servlet源代码如下：
package com.soft.MyFirstWebProject.servlet;
import java.io.IOException;
import java.io.PrintWriter;
import javax.servlet.ServletException;
import javax.servlet.http.HttpServlet;
import javax.servlet.http.HttpServletRequest;
import javax.servlet.http.HttpServletResponse;
import com.soft.MyFirstWebProject.service.IUserService;
import com.soft.MyFirstWebProject.service.UserServiceImpl;
@SuppressWarnings("serial")
public class LoginSerlvet extends HttpServlet {
private IUserService service=new UserServiceImpl();
public void doGet(HttpServletRequest request, HttpServletResponse response)
throws ServletException, IOException {
doPost(request,response);
}
public void doPost(HttpServletRequest request, HttpServletResponse response)
throws ServletException, IOException {
String uid=request.getParameter("uid");
String pwd=request.getParameter("pwd");
if (service.login(uid, pwd)){
request.getRequestDispatcher("index.jsp").forward(request, response);
}else{
request.getRequestDispatcher("error.jsp").forward(request, response);
}
}
}
servlet调用的login方法如下：
public class UserServiceImpl implements IUserService {
private DbHelperImpl dao=new DbHelperImpl();
public boolean login(String uid, String pwd) {
String sql="select count(*) n from userinfo where userid=? and userpwd=?";
Object[] params={uid,pwd};
Map row=dao.runSelect(sql, params)[0];
int n=Integer.parseInt(row.get("n").toString());
return n==1;
}
}
------解决方案--------------------
java.lang.ClassNotFoundException: com.soft.whdx.servlet.LoginSerlvet
找不到 。看看是否存在或者路径对不。
------解决方案--------------------
如果不存在，就可能是程序那行代码有错，没有编译成功