HTTP Status 500 - 

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

type Exception report

message 

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

exception 

javax.servlet.ServletException: Servlet.init() for servlet CreateDBServlet threw exception
    org.apache.catalina.valves.ErrorReportValve.invoke(ErrorReportValve.java:118)
    org.apache.coyote.tomcat5.CoyoteAdapter.service(CoyoteAdapter.java:160)
    org.apache.coyote.http11.Http11Processor.process(Http11Processor.java:799)
    org.apache.coyote.http11.Http11Protocol$Http11ConnectionHandler.processConnection(Http11Protocol.java:705)
    org.apache.tomcat.util.net.TcpWorkerThread.runIt(PoolTcpEndpoint.java:577)
    org.apache.tomcat.util.threads.ThreadPool$ControlRunnable.run(ThreadPool.java:683)
    java.lang.Thread.run(Thread.java:595)


root cause 

java.lang.NullPointerException
    java.lang.Class.forName0(Native Method)
    java.lang.Class.forName(Class.java:164)
    org.sunxin.lesson.jsp.bookstore.CreateDBServlet.init(CreateDBServlet.java:22)
    javax.servlet.GenericServlet.init(GenericServlet.java:211)
    org.apache.catalina.valves.ErrorReportValve.invoke(ErrorReportValve.java:118)
    org.apache.coyote.tomcat5.CoyoteAdapter.service(CoyoteAdapter.java:160)
    org.apache.coyote.http11.Http11Processor.process(Http11Processor.java:799)
    org.apache.coyote.http11.Http11Protocol$Http11ConnectionHandler.processConnection(Http11Protocol.java:705)
    org.apache.tomcat.util.net.TcpWorkerThread.runIt(PoolTcpEndpoint.java:577)
    org.apache.tomcat.util.threads.ThreadPool$ControlRunnable.run(ThreadPool.java:683)
    java.lang.Thread.run(Thread.java:595)


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

这是抱的错！

package org.sunxin.lesson.jsp.bookstore;

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

public class CreateDBServlet extends HttpServlet
{
    private String url;
    private String user;
    private String password;
    
    public void init() throws ServletException
    {
        String driverClass=getInitParameter("driverClass");
        url=getInitParameter("url");
        user=getInitParameter("user");
        password=getInitParameter("password");
        try
        {
            Class.forName(driverClass);
        }
        catch(ClassNotFoundException ce)
        {
            throw new UnavailableException("加载数据库驱动失败！");
        }
    }
    
    public void doGet(HttpServletRequest req, HttpServletResponse resp)
               throws ServletException,IOException
    {
        Connection conn=null;
        Statement stmt=null;
        try
        {
            conn=DriverManager.getConnection(url,user,password);
            stmt=conn.createStatement();
            stmt.executeUpdate("create database bookstore");
            stmt.executeUpdate("use bookstore");
            stmt.executeUpdate("create table bookinfo(id INT not null primary key,title VARCHAR(50) not null,author VARCHAR(50) not null,bookconcern VARCHAR(100) not null,publish_date DATE not null,price FLOAT(4,2) not null,amount SMALLINT,remark VARCHAR(200)) ENGINE=InnoDB");
            stmt.addBatch("insert into bookinfo values(1,'Java从入门到精通','张三','张三出版社','2004-6-1',34.00,35,null)");
            stmt.addBatch("insert into bookinfo values(2,'JSP深入编程','李四','李四出版社','2004-10-1',56.00,20,null)");
            stmt.addBatch("insert into bookinfo values(3,'J2EE高级编程','王五','王五出版社','2005-3-1',78.00,10,null)");
            stmt.executeBatch();
            
            PrintWriter out=resp.getWriter();
            out.println("success!");
            out.close();
        }
        catch(SQLException se)
        {
            se.printStackTrace();
        }
        finally
        {
            if(stmt!=null)
            {
                try
                {
                    stmt.close();
                }
                catch(SQLException se)
                {
                    se.printStackTrace();
                }
                stmt=null;
            }
            if(conn!=null)
            {
                try
                {
                    conn.close();
                }
                catch(SQLException se)
                {
                    se.printStackTrace();
                }
                conn=null;
            }
        }
    }
}

这是原程序，我从书上抄下来的，没错！

就是连不了库~！！！！！！！！！！！！

为什么？？？？？？？？？？？？？？？？

兄弟姐妹们快来帮帮忙！！
 
 
 
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