MyBatis 基本演示

主配置文件

 1 <?xml version="1.0" encoding="UTF-8" ?>
 2 
 3 <!DOCTYPE configuration
 4     PUBLIC "-//mybatis.org//DTD Config 3.0//EN"
 5     "http://mybatis.org/dtd/mybatis-3-config.dtd">
 6 
 7 <configuration>
 8 
 9   <settings>
10     <setting name="useGeneratedKeys" value="false"/>
11     <setting name="useColumnLabel" value="true"/>
12   </settings>
13 
14   <typeAliases>
15     <typeAlias alias="UserAlias" type="org.apache.ibatis.submitted.complex_property.User"/>
16   </typeAliases> -
17   <environments default="development">
18     <environment id="development">
19       <transactionManager type="JDBC">
20         <property name="" value=""/>
21       </transactionManager>
22       <dataSource type="UNPOOLED">
23         <property name="driver" value="com.mysql.jdbc.Driver"/>
24         <property name="url" value="jdbc:mysql://127.0.0.1:3306/micro_message"/>
25         <property name="username" value="root"/>
26         <property name="password" value="root"/>
27       </dataSource>
28     </environment>
29   </environments>
30   
31   <mappers>
32     <mapper resource="com/imooc/config/sqlxml/Message.xml"/>
33   </mappers>
34 
35 </configuration>

映射文件

 1 <?xml version="1.0" encoding="UTF-8"?>
 2 <!DOCTYPE mapper
 3     PUBLIC "-//mybatis.org//DTD Mapper 3.0//EN"
 4     "http://mybatis.org/dtd/mybatis-3-mapper.dtd">
 5 
 6 <mapper namespace="org.zln.domain.Message">
 7 
 8     <resultMap id="messageResult" type="message">
 9         <id property="id" column="ID" jdbcType="INTEGER"/>
10         <result property="command" column="COMMAND" jdbcType="VARCHAR"/>
11         <result property="description" column="DESCRIPTION" jdbcType="VARCHAR"/>
12         <result property="content" column="CONTENT" jdbcType="VARCHAR"/>
13     </resultMap>
14 
15     <select id="queryMessageList" resultMap="messageResult">
16         SELECT id,command,description,content FROM message
17     </select>
18 </mapper>

初始化配置文件

 1 package com.imooc.db;
 2 
 3 import java.io.IOException;
 4 import java.io.Reader;
 5 
 6 import org.apache.ibatis.io.Resources;
 7 import org.apache.ibatis.session.SqlSession;
 8 import org.apache.ibatis.session.SqlSessionFactory;
 9 import org.apache.ibatis.session.SqlSessionFactoryBuilder;
10 
11 /**
12  * 访问数据库类
13  */
14 public class DBAccess {
15     public SqlSession getSqlSession() throws IOException {
16         // 通过配置文件获取数据库连接信息
17         Reader reader = Resources.getResourceAsReader("com/imooc/config/Configuration.xml");
18         // 通过配置信息构建一个SqlSessionFactory
19         SqlSessionFactory sqlSessionFactory = new SqlSessionFactoryBuilder().build(reader);
20         // 通过sqlSessionFactory打开一个数据库会话
21         SqlSession sqlSession = sqlSessionFactory.openSession();
22         return sqlSession;
23     }
24 }

Dao

 1 package org.zln.dao;
 2 
 3 import org.springframework.stereotype.Repository;
 4 import org.zln.domain.Message;
 5 
 6 import java.util.List;
 7 
 8 /**
 9  * Created by sherry on 000006/7/6 19:16.
10  */
11 @Repository
12 public class MessageDao extends BaseDao {
13 
14     public List<Message> queryMessageList(String command,String description){
15         return sqlSessionTemplate.selectList("org.zln.domain.Message.queryMessageList");
16     }
17 }

在MyBatis中，必须使用命名空间，不是在调用sql的时候，没有书写命名空间也能找到对应的id