java web开发详解 出错404

搞了4个小时，完全没用，特来求助大家！

Java code:

package les8;

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

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 e) {
throw new UnavailableException("加载数据库驱动失败");
}
}

protected 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,&q