Eclipse+tomcat问题

[xjw_genius]

各位大哥好，用Eclipse写好的JSP程序，通过tomcat发布后，在网页上输入网址后，出现Apache Tomcat/5.0.28 error Report.

HTTP Status 500 -

--------------------------------------------------------------------------------

type Exception report

message

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

exception

org.apache.jasper.JasperException
org.apache.jasper.servlet.JspServletWrapper.service(JspServletWrapper.java:372)
org.apache.jasper.servlet.JspServlet.serviceJspFile(JspServlet.java:292)
org.apache.jasper.servlet.JspServlet.service(JspServlet.java:236)
javax.servlet.http.HttpServlet.service(HttpServlet.java:802)


root cause

java.lang.NullPointerException
until.login.excute(login.java:61)
org.apache.jsp.login_jsp._jspService(login_jsp.java:67)
org.apache.jasper.runtime.HttpJspBase.service(HttpJspBase.java:94)
javax.servlet.http.HttpServlet.service(HttpServlet.java:802)
org.apache.jasper.servlet.JspServletWrapper.service(JspServletWrapper.java:324)
org.apache.jasper.servlet.JspServlet.serviceJspFile(JspServlet.java:292)
org.apache.jasper.servlet.JspServlet.service(JspServlet.java:236)
javax.servlet.http.HttpServlet.service(HttpServlet.java:802)


note The full stack trace of the root cause is available in the Apache Tomcat/5.0.28 logs.

请问这个服务器碰到内部错误的问题一般有哪些，该怎么解决呢，我弄了半天了，谢谢。

[awusoft]

这个是空指针错误.要看你的代码才能判断了

[hello_zhenyu]

你这样给你找不出来问题，把代码贴出来！

[54powerman]

很清楚了。
until.login.excute(login.java:61)

贴出这行

[xjw_genius]

[Quote=引用 3 楼 54powerman 的回复:]
很清楚了。
until.login.excute(login.java:61)

贴出这行
[/Quote]
谢谢，关于login.excute的代码是：
public boolean excute() throws Exception
{
boolean flag = false;
rs = stmt.executeQuery("select * from userInfo where Name='lab' and Password='lab' "); if(rs.next())
{
//if ("tao" == rs.getString("Name"))
flag = true;
}

rs.close();
return flag;
}

[xjw_genius]

这个单元的代码是：
package until;

import java.sql.*;


public class login extends DataBase {
private String username; //登录用户名
private String passwd; //登录密码
private boolean isadmin; //是否管理员登录
private long userid=0; //用户ID号


public login() throws Exception{
super(3);
username = "";
passwd = "";
isadmin = false;
}

public String getUsername() {
return username;
}
public void setUsername(String newusername) {
username = newusername;
}

public String getPasswd() {
return passwd;
}
public void setPasswd(String newpasswd) {
passwd = newpasswd;
}

public boolean getIsadmin() {
return isadmin;
}
public void setIsadmin(boolean newIsadmin) {
isadmin = newIsadmin;
}

public long getUserid() {
return userid;
}

public void setUserid (long uid) {
userid = uid;
}

public String getSql() {
if (isadmin) {
sqlStr = "select * from my_BookAdminuser where adminuser = '" + strFormat.toSql(username) + "' and adminpass = '" + strFormat.toSql(passwd) + "'";
}else {
sqlStr = "select * from my_users where username = '" + strFormat.toSql(username) + "' and password = '" + strFormat.toSql(passwd) + "'";
}
return sqlStr;
}

public boolean excute() throws Exception {
boolean flag = false;
// rs = stmt.executeQuery("select * from userInfo where Name = '" + strFormat.toSql(username) + "' and Password = '" + strFormat.toSql(passwd) + "'");
rs = stmt.executeQuery("select * from userInfo where Name='lab' and Password='lab' ");
if(rs.next())
{
//if ("tao" == rs.getString("Name"))
flag = true;
}

rs.close();
return flag;

}
};

还望各位大哥帮忙解决下。很急，谢谢！

[xjw_genius]

请各位大哥大姐帮帮忙。