mybatis练习时出的错

[LiuYangBelieve]

下面是运行后报的错误
严重: Servlet.service() for servlet [ListServlet] in context with path [/MicroMessage] threw exception [Servlet execution threw an exception] with root cause
java.lang.ClassNotFoundException: org.apache.ibatis.io.Resources
at org.apache.catalina.loader.WebappClassLoaderBase.loadClass(WebappClassLoaderBase.java:1892)
at org.apache.catalina.loader.WebappClassLoaderBase.loadClass(WebappClassLoaderBase.java:1735)
at com.imooc.db.DBAccess.getSqlSession(DBAccess.java:17)
at com.imooc.dao.MessageDao.queryMessageList(MessageDao.java:30)
at com.imooc.service.ListService.queryMessageList(ListService.java:14)
at com.imooc.servlet.ListServlet.doGet(ListServlet.java:81)
at javax.servlet.http.HttpServlet.service(HttpServlet.java:624)
at javax.servlet.http.HttpServlet.service(HttpServlet.java:731)
at org.apache.catalina.core.ApplicationFilterChain.internalDoFilter(ApplicationFilterChain.java:303)
at org.apache.catalina.core.ApplicationFilterChain.doFilter(ApplicationFilterChain.java:208)
at org.apache.tomcat.websocket.server.WsFilter.doFilter(WsFilter.java:52)
at org.apache.catalina.core.ApplicationFilterChain.internalDoFilter(ApplicationFilterChain.java:241)
at org.apache.catalina.core.ApplicationFilterChain.doFilter(ApplicationFilterChain.java:208)
at org.apache.catalina.core.StandardWrapperValve.invoke(StandardWrapperValve.java:218)
at org.apache.catalina.core.StandardContextValve.invoke(StandardContextValve.java:110)
at org.apache.catalina.authenticator.AuthenticatorBase.invoke(AuthenticatorBase.java:506)
at org.apache.catalina.core.StandardHostValve.invoke(StandardHostValve.java:169)
at org.apache.catalina.valves.ErrorReportValve.invoke(ErrorReportValve.java:103)
at org.apache.catalina.valves.AccessLogValve.invoke(AccessLogValve.java:962)
at org.apache.catalina.core.StandardEngineValve.invoke(StandardEngineValve.java:116)
at org.apache.catalina.connector.CoyoteAdapter.service(CoyoteAdapter.java:445)
at org.apache.coyote.http11.AbstractHttp11Processor.process(AbstractHttp11Processor.java:1087)
at org.apache.coyote.AbstractProtocol$AbstractConnectionHandler.process(AbstractProtocol.java:637)
at org.apache.tomcat.util.net.AprEndpoint$SocketProcessor.doRun(AprEndpoint.java:2536)
at org.apache.tomcat.util.net.AprEndpoint$SocketProcessor.run(AprEndpoint.java:2525)
at java.util.concurrent.ThreadPoolExecutor.runWorker(ThreadPoolExecutor.java:1142)
at java.util.concurrent.ThreadPoolExecutor$Worker.run(ThreadPoolExecutor.java:617)
at org.apache.tomcat.util.threads.TaskThread$WrappingRunnable.run(TaskThread.java:61)
at java.lang.Thread.run(Thread.java:745)

下面是代码
Message.xml
<?xml version="1.0" encoding="UTF-8"?>
<!--

Copyright 2009-2012 the original author or authors.

Licensed under the Apache License, Version 2.0 (the "License");
you may not use this file except in compliance with the License.
You may obtain a copy of the License at

http://www.apache.org/licenses/LICENSE-2.0

Unless required by applicable law or agreed to in writing, software
distributed under the License is distributed on an "AS IS" BASIS,
WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
See the License for the specific language governing permissions and
limitations under the License.

-->

<!DOCTYPE mapper
PUBLIC "-//mybatis.org//DTD Mapper 3.0//EN"
"http://mybatis.org/dtd/mybatis-3-mapper.dtd">

<mapper namespace="Message">

<resultMap type="com.imooc.bean.Message" id="MessageResult">
<id column="ID" jdbcType="INTEGER" property="id"/>
<result column="COMMAND" jdbcType="VARCHAR" property="command"/>
<result column="DESCRIPTION" jdbcType="VARCHAR" property="description"/>
<result column="CONTENT" jdbcType="VARCHAR" property="content"/>
</resultMap>

<select id="queryMessageList" resultMap="MessageResult">
select ID,COMMAND,DESCRIPTION,CONTENT from MESSAGE where 1=1
</select>

</mapper>


下面是DBAccess.java
package com.imooc.db;

import java.io.IOException;
import java.io.Reader;

import org.apache.ibatis.io.Resources;
import org.apache.ibatis.session.SqlSession;
import org.apache.ibatis.session.SqlSessionFactory;
import org.apache.ibatis.session.SqlSessionFactoryBuilder;

/**
* 访问数据库类
*/
public class DBAccess {
public SqlSession getSqlSession() throws IOException {
// 通过配置文件获取数据库连接信息
Reader reader = Resources.getResourceAsReader("com/imooc/config/Configuration.xml");
// 通过配置信息构建一个SqlSessionFactory
SqlSessionFactory sqlSessionFactory = new SqlSessionFactoryBuilder().build(reader);
// 通过sqlSessionFactory打开一个数据库会话
SqlSession sqlSession = sqlSessionFactory.openSession();
return sqlSession;
}
}

下面是Configuration.xml
<?xml version="1.0" encoding="UTF-8" ?>
<!--

Copyright 2009-2012 the original author or authors.

Licensed under the Apache License, Version 2.0 (the "License");
you may not use this file except in compliance with the License.
You may obtain a copy of the License at

http://www.apache.org/licenses/LICENSE-2.0

Unless required by applicable law or agreed to in writing, software
distributed under the License is distributed on an "AS IS" BASIS,
WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
See the License for the specific language governing permissions and
limitations under the License.

-->
<!DOCTYPE configuration
PUBLIC "-//mybatis.org//DTD Config 3.0//EN"
"http://mybatis.org/dtd/mybatis-3-config.dtd">

<configuration>
<!--
<settings>
<setting name="useGeneratedKeys" value="false"/>
<setting name="useColumnLabel" value="true"/>
</settings>

<typeAliases>
<typeAlias alias="UserAlias" type="org.apache.ibatis.submitted.complex_property.User"/>
</typeAliases> -->


<environments default="development">
<environment id="development">
<transactionManager type="JDBC">
<property name="" value=""/>
</transactionManager>
<dataSource type="UNPOOLED">
<property name="driver" value="com.mysql.jdbc.Driver"/>
<property name="url" value="jdbc:mysql://127.0.0.1:3306/micro_message?characterEncoding=utf8"/>
<property name="username" value="root"/>
<property name="password" value="123456"/>
</dataSource>
</environment>
</environments>

<mappers>
<mapper resource="com/imooc/config/sqlxml/Message.xml"/>
</mappers>

</configuration>

下面是MessageDao.java
package com.imooc.dao;

import java.io.IOException;
import java.sql.Connection;
import java.sql.DriverManager;
import java.sql.PreparedStatement;
import java.sql.ResultSet;
import java.sql.SQLException;
import java.util.ArrayList;
import java.util.List;

import org.apache.ibatis.session.SqlSession;

import com.imooc.bean.Message;
import com.imooc.db.DBAccess;

/**
* 和message表相关的数据库操作
*/
public class MessageDao {

/**
* 根据查询条件查询消息列表
*/
public List<Message> queryMessageList(String command,String description){
DBAccess dbAccess = new DBAccess();
List<Message> messageList = new ArrayList<Message>();
SqlSession sqlSession = null;
try {
sqlSession = dbAccess.getSqlSession();
//通过sqlSession执行SQL语句
messageList = sqlSession.selectList("Message.queryMessageList");
} catch (IOException e) {
e.printStackTrace();
}finally{
if(sqlSession != null){
sqlSession.close();
}
}
return messageList;
}

public static void main(String[] args){
MessageDao messageDao = new MessageDao();
messageDao.queryMessageList("", "");
}

}