Topic: jsp+javabean 出错请求帮助

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1.jsp+javabean 出错请求帮助 Copy to clipboard
Posted by: athen
Posted on: 2005-04-18 23:20

我一共有三段代码 UserEntity操作数据库， Cart 逻辑操作，cartform.jsp界面 出现异常为
type Exception report

message

description The server encountered an internal error () that prevented it from fulfilling this request.

exception

org.apache.jasper.JasperException
  at org.apache.jasper.servlet.JspServletWrapper.service(JspServletWrapper.java:254)
  at org.apache.jasper.servlet.JspServlet.serviceJspFile(JspServlet.java:295)
  at org.apache.jasper.servlet.JspServlet.service(JspServlet.java:241)
  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 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.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:2422)
  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:163)
  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:199)
  at org.apache.coyote.http11.Http11Processor.process(Http11Processor.java:828)
  at org.apache.coyote.http11.Http11Protocol$Http11ConnectionHandler.processConnection(Http11Protocol.java:700)
  at org.apache.tomcat.util.net.TcpWorkerThread.runIt(PoolTcpEndpoint.java:584)
  at org.apache.tomcat.util.threads.ThreadPool$ControlRunnable.run(ThreadPool.java:683)
  at java.lang.Thread.run(Thread.java:536)

root cause

java.lang.NullPointerException
  at cart.UserEntity.queryUser(UserEntity.java:40)
  at cart.Cart.checkUser(Cart.java:13)
  at org.apache.jsp.cartform_jsp._jspService(cartform_jsp.java:81)
  at org.apache.jasper.runtime.HttpJspBase.service(HttpJspBase.java:137)
  at javax.servlet.http.HttpServlet.service(HttpServlet.java:853)
  at org.apache.jasper.servlet.JspServletWrapper.service(JspServletWrapper.java:210)
  at org.apache.jasper.servlet.JspServlet.serviceJspFile(JspServlet.java:295)
  at org.apache.jasper.servlet.JspServlet.service(JspServlet.java:241)
  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 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.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:2422)
  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:163)
  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:199)
  at org.apache.coyote.http11.Http11Processor.process(Http11Processor.java:828)
  at org.apache.coyote.http11.Http11Protocol$Http11ConnectionHandler.processConnection(Http11Protocol.java:700)
  at org.apache.tomcat.util.net.TcpWorkerThread.runIt(PoolTcpEndpoint.java:584)
  at org.apache.tomcat.util.threads.ThreadPool$ControlRunnable.run(ThreadPool.java:683)
  at java.lang.Thread.run(Thread.java:536)

原代码
type Exception report

message

description The server encountered an internal error () that prevented it from fulfilling this request.

exception

org.apache.jasper.JasperException
  at org.apache.jasper.servlet.JspServletWrapper.service(JspServletWrapper.java:254)
  at org.apache.jasper.servlet.JspServlet.serviceJspFile(JspServlet.java:295)
  at org.apache.jasper.servlet.JspServlet.service(JspServlet.java:241)
  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 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.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:2422)
  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:163)
  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:199)
  at org.apache.coyote.http11.Http11Processor.process(Http11Processor.java:828)
  at org.apache.coyote.http11.Http11Protocol$Http11ConnectionHandler.processConnection(Http11Protocol.java:700)
  at org.apache.tomcat.util.net.TcpWorkerThread.runIt(PoolTcpEndpoint.java:584)
  at org.apache.tomcat.util.threads.ThreadPool$ControlRunnable.run(ThreadPool.java:683)
  at java.lang.Thread.run(Thread.java:536)

root cause

java.lang.NullPointerException
  at cart.UserEntity.queryUser(UserEntity.java:40)
  at cart.Cart.checkUser(Cart.java:13)
  at org.apache.jsp.cartform_jsp._jspService(cartform_jsp.java:81)
  at org.apache.jasper.runtime.HttpJspBase.service(HttpJspBase.java:137)
  at javax.servlet.http.HttpServlet.service(HttpServlet.java:853)
  at org.apache.jasper.servlet.JspServletWrapper.service(JspServletWrapper.java:210)
  at org.apache.jasper.servlet.JspServlet.serviceJspFile(JspServlet.java:295)
  at org.apache.jasper.servlet.JspServlet.service(JspServlet.java:241)
  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 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.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:2422)
  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:163)
  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:199)
  at org.apache.coyote.http11.Http11Processor.process(Http11Processor.java:828)
  at org.apache.coyote.http11.Http11Protocol$Http11ConnectionHandler.processConnection(Http11Protocol.java:700)
  at org.apache.tomcat.util.net.TcpWorkerThread.runIt(PoolTcpEndpoint.java:584)
  at org.apache.tomcat.util.threads.ThreadPool$ControlRunnable.run(ThreadPool.java:683)
  at java.lang.Thread.run(Thread.java:536)

package cart;
import java.io.*;
import java.sql.*;
import java.math.*;
import java.util.*;
public class Cart {
private String username=new String("");
public Cart(){}
public int checkUser(String username,String userpassword){
int result=1;
UserEntity user=null;
try{
user=UserEntity.queryUser(username);
}catch(SQLException e){e.getMessage();}
if(user==null)
return 0;
String pass=user.getUserPassword();
if(pass.compareTo(userpassword)==0)
{
result=1;
this.username=username;
}
return result;
}

}

<%@ page contentType="text/html;charset=GB2312" %>
<meta http-equiv="Content-Type" content="text/html; charset=gb2312">
<meta name="GENERATOR" content="Microsoft FrontPage 4.0">
<meta name="ProgId" content="FrontPage.Editor.Document">
<%@ page language="java" import="java.util.*" %>
<%@ page import="java.math.*" %>
<%@ page import="java.lang.*" %>
<%@ page import="java.io.*" %>
<%@ page import="cart.*" %>
<html>
<head>
<title>
cartform
</title>
</head>
<jsp:useBean id="bean0" scope="session" class="cart.Cart"/>
<jsp:setProperty name="bean0" property="*" />
<%

String loginInfo="欢迎你";
Cart ct=new Cart();
int result=ct.checkUser(request.getParameter("userName"),request.getParameter("userPassword"));
if(result==1)
      loginInfo="登录成功!欢迎你";
    else
      loginInfo="登录失败!";

%>
<body bgcolor="#ffffff">
<h1>
用户提交实验
</h1>
<form method="POST" action="cartform.jsp">
<br><br>
<tr bgcolor="pink"><td>登录</td></tr>
<tr><td>用户名:<input type="text" name="userName" size="10"></td></tr>
<tr><td>密  码:<input type="text" name="userPassword" size="10"></td></tr>
<input type="submit" name="提交" value="Submit">
<input type="reset" value="重置">
<hr>bean0<br>
<hr><br>
</form>
<%=loginInfo%>
</body>
</html>
2.Re:jsp+javabean 出错请求帮助 [Re: athen] Copy to clipboard
Posted by: athen
Posted on: 2005-04-18 23:21

发错了 一段代码
package cart;
import java.sql.*;
import java.util.*;
import java.math.*;
import java.lang.*;
import com.microsoft.jdbc.sqlserver.*;

public class UserEntity {
private String id;
private String username;
private String userpassword;
public static String Str="com.microsoft.jdbc.sqlserver.SQLServerDriver";
public static String url="jdbc:microsoft:sqlserver://localhost:1433;DatabaseName=tzj";
public static Connection conn=null;
public UserEntity(String id,String username,String userpassword) {

try{
Class.forName(Str);
}catch(java.lang.ClassNotFoundException e){e.getMessage();}

this.id=id;
this.username=username;
this.userpassword=userpassword;
}
public static UserEntity queryUser(String username) throws SQLException{
try{
Class.forName(Str);
}catch(java.lang.ClassNotFoundException e){e.getMessage();}
String sql="select user_id,user_name,user_password from user where user_password=?";
ResultSet rs=null;
try{

conn=DriverManager.getConnection(url);
PreparedStatement prepStmt=conn.prepareStatement(sql);
prepStmt.setString(1,username);
rs=prepStmt.executeQuery();
}catch(SQLException e){e.getMessage();}

UserEntity user=null;
if(rs.next())

user=new UserEntity(rs.getString(1),rs.getString(2),rs.getString(3));
return user;

}
public String getUserPassword(){

return userpassword;
}
public String getUserName(){
return username;
}
}
3.Re:jsp+javabean 出错请求帮助 [Re: athen] Copy to clipboard
Posted by: hh0514
Posted on: 2005-04-21 09:04

你把这里改成这样的看看,我以前经常出现这样的错误

.......
UserEntity user=null;
if(rs.next()) // 改成if( (rs!=null) && (rs.next()) )

user=new UserEntity(rs.getString(1),rs.getString(2),rs.getString(3));
return user;

}
public String getUserPassword(){

return userpassword;
}
public String getUserName(){
return username;
}
}

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