[code="java"][/code]我是个Java开发的初学者，最近开始自学Servlet/JSP编程，参考的是孙鑫老师编的《Servlet/Jsp深入详解——基于Tomcat的Web开发》。
在学习“第4章数据库访问”时遇到了问题，我按照书上的代码编写了一个CreateDBServlet.java用于连接数据库，编译是没问题的。进行了部署和配置后，访问时出错了，浏览器显示的错误信息如下：
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: java.sql.SQLException: Access denied for user 'root'@'localhost' (using password: NO)
org.sunxin.ch04.servlet.CreateDBServlet.doGet(CreateDBServlet.java:61)
javax.servlet.http.HttpServlet.service(HttpServlet.java:617)
javax.servlet.http.HttpServlet.service(HttpServlet.java:717)
root cause
java.sql.SQLException: Access denied for user 'root'@'localhost' (using password: NO)
com.mysql.jdbc.SQLError.createSQLException(SQLError.java:1055)
com.mysql.jdbc.SQLError.createSQLException(SQLError.java:956)
com.mysql.jdbc.MysqlIO.checkErrorPacket(MysqlIO.java:3491)
com.mysql.jdbc.MysqlIO.checkErrorPacket(MysqlIO.java:3423)
com.mysql.jdbc.MysqlIO.checkErrorPacket(MysqlIO.java:910)
com.mysql.jdbc.MysqlIO.secureAuth411(MysqlIO.java:3923)
com.mysql.jdbc.MysqlIO.doHandshake(MysqlIO.java:1273)
com.mysql.jdbc.ConnectionImpl.createNewIO(ConnectionImpl.java:2031)
com.mysql.jdbc.ConnectionImpl.(ConnectionImpl.java:718)
com.mysql.jdbc.ConnectionImpl.getInstance(ConnectionImpl.java:298)
com.mysql.jdbc.NonRegisteringDriver.connect(NonRegisteringDriver.java:282)
java.sql.DriverManager.getConnection(DriverManager.java:525)
java.sql.DriverManager.getConnection(DriverManager.java:171)
org.sunxin.ch04.servlet.CreateDBServlet.doGet(CreateDBServlet.java:44)
javax.servlet.http.HttpServlet.service(HttpServlet.java:617)
javax.servlet.http.HttpServlet.service(HttpServlet.java:717)
note The full stack trace of the root cause is available in the Apache Tomcat/6.0.18 logs.
Apache Tomcat/6.0.18
CreateDBServlet代码如下：
[code="java"]package org.sunxin.ch04.servlet;
import java.io.IOException;
import java.io.PrintWriter;
import java.sql.Connection;
import java.sql.DriverManager;
import java.sql.SQLException;
import java.sql.Statement;
import javax.servlet.ServletException;
import javax.servlet.http.HttpServlet;
import javax.servlet.http.HttpServletRequest;
import javax.servlet.http.HttpServletResponse;
public class CreateDBServlet extends HttpServlet
{
private String userUrl;
private String userName;
private String password;
public void init() throws ServletException
{
String driverClass=getInitParameter("driverClass");
userUrl=getInitParameter("userUrl");
userName=getInitParameter("userName");
password=getInitParameter("password");
try
{
Class.forName(driverClass);
}
catch (ClassNotFoundException ce)
{
throw new ServletException("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(userUrl,userName,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(50) 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 Web 详解','孙鑫','电子工业出版社','2006-4-20',99.00,35,null)");
stmt.addBatch("insert into bookinfo values(2,'Struts 2深入详解','孙鑫','电子工业出版社','2008-6-15',79.00,20,null)");
stmt.addBatch("insert into bookinfo values(3,'Servlet/JSP详解','孙鑫','电子工业出版社','2008-7-1',79.00,10,null)");
stmt.executeBatch();
resp.setContentType("text/html;charset=GBK");
PrintWriter out=resp.getWriter();
out.println("数据库创建成功！");
out.close();
}
catch (SQLException se)
{
throw new ServletException(se);
}
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;
}
}
}
}[/code]
web.xml文件如下：
[code="java"]<?xml version="1.0" encoding="gb2312"?>
xmlns="http://java.sun.com/xml/ns/javaee"
xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
xsi:schemaLocation="http://java.sun.com/xml/ns/javaee
http://java.sun.com/xml/ns/javaee/web-app_2_5.xsd">
<servlet>
<servlet-name>createDB</servlet-name>
<servlet-class>org.sunxin.ch04.servlet.CreateDBServlet</servlet-class>
<init-param>
<param-name>driverClass</param-name>
<param-value>com.mysql.jdbc.Driver</param-value>
</init-param>
<init-param>
<param-name>userUrl</param-name>
<param-value>jdbc:mysql://localhost:3306</param-value>
</init-param>
<init-param>
<param-name>userName</param-name>
<param-value>root</param-value>
</init-param>
<init-param>
<param-name>passord</param-name>
<param-value>12345678</param-value>
</init-param>
</servlet>
<servlet-mapping>
<servlet-name>createDB</servlet-name>
<url-pattern>/createdb</url-pattern>
</servlet-mapping>
[/code]
[quote]exception
javax.servlet.ServletException: com.mysql.jdbc.exceptions.MySQLSyntaxErrorException: You have an error in your SQL syntax; check the manual that corresponds to your MySQL server version for the right syntax to use near 'exits bookstore' at line 1 [/quote]
这个是在你写的sql语句中有语法错误。
逻辑是先判断有删除 你的exits用法不对。
[quote]javax.servlet.ServletException: java.sql.SQLException: Access denied for user 'root'@'localhost' (using password: NO)[/quote]
数据库访问被拒了，检查一下帐号密码是否正确？
这个好解决，重新设置密码。
一些设置密码指令：
[url]http://www.debian-administration.org/articles/442[/url]
CreateDbServlet中的从45到52行代码都可以注释掉的。这个不影响你连接数据库的。如果连接不成功的话 它还是会报错的。
或者你直接把连接数据库的那个给写成一个类的一个static方法，在要连接的时候直接用类名去调用就ok了。
不知道我把问题看清楚了没，你看看。。。
exits 拼错了,是exists
建议你还是在数据库里先建好了表,在去操作数据,不要每次都去建库,建表
两处都是平写错误。。。
[quote]passord[/quote]
web.xml里passord拼错了，应该是password
[quote]stmt.executeUpdate("drop database if exits bookstore"); [/quote]
exits拼错了，应该是exists
web.xml里passord拼错了，应该是password