通过读取web.xml文件中的配置参数连接数据库(原)

通过读取web.xml文件中的配置参数连接数据库

1.问题提出

-javax.servlet.ServletException: Servlet.init() for servlet CreateDBServlet threw exception

这个错误是在看孙鑫老师的那本web编程详解，在第八章遇见的，就是第一个例子

但总是运行不成功。仔细观察发现自己犯了两个错误。

(1)CreateDBServlet.java代码

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.execute