MyBatis入门学习

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本文主要介绍MyBatis的入门基础，转载博客的原文http://blog.csdn.net/huzheaccp/article/details/7399124

所需要jar包：mybatis-3.x.x.jar 、如果需要和spring整合，还需要加入相关的包

1：看项目目录红颜色不要关心

2：按照步骤：

1：加入jar包

2：创建数据源（configuration.xml）创建数据库（此处省略）

<?xml version="1.0" encoding="UTF-8" ?>   <!DOCTYPE configuration       PUBLIC "-//mybatis.org//DTD Config 3.0//EN"       "http://mybatis.org/dtd/mybatis-3-config.dtd"><configuration><typeAliases><!--给实体类起一个别名 user --><typeAlias type="com.forum.po.User" alias="User" /></typeAliases><!--数据源配置  这块用 BD2数据库 --><environments default="development"><environment id="development"><transactionManager type="jdbc" /><dataSource type="POOLED"><property name="driver" value="com.ibm.db2.jcc.DB2Driver" /><property name="url" value="jdbc:db2://localhost:50000/forum" /><property name="username" value="DB2ADMIN" /><property name="password" value="admin" /></dataSource></environment></environments><mappers><!--userMapper.xml装载进来  同等于把“dao”的实现装载进来 --><mapper resource="myBatis/userMapper.xml" /></mappers></configuration>

3：创建实体类USER

package com.forum.po;/** * 用户类 *  * @author db2admin *  */public class User extends Entity {private String name;private Integer age;public String getName() {return name;}public void setName(String name) {this.name = name;}public Integer getAge() {return age;}public void setAge(Integer age) {this.age = age;}public User() {}}

4：创建dao接口、可以说是Mapper接口：UserMapper

package com.forum.dao;import com.forum.po.User;public interface UserMapper {public User findById(String Id);}

5:创建dao的实现，不同于hibernarte的此处的实现为一个xml文件，也就是userMapper.xml

<?xml version="1.0" encoding="UTF-8" ?><!DOCTYPE mapper PUBLIC     "-//mybatis.org//DTD Mapper 3.0//EN"    "http://mybatis.org/dtd/mybatis-3-mapper.dtd"><!--这块等于dao接口的实现  namespace必须和接口的类路径一样--><mapper namespace="com.forum.dao.UserMapper"><!-- findById必须和接口中的方法名一样  返回一个User  就是刚才的别名  如果不弄别名要连类路径一起写 麻烦--><select id="findById" parameterType="HashMap" resultType="User">select* from butone.student where id=#{id}    </select></mapper>

6:测试类，MyBatisTest

package com.forum.test;import java.io.IOException;import org.apache.ibatis.io.Resources;import org.apache.ibatis.session.SqlSession;import org.apache.ibatis.session.SqlSessionFactory;import org.apache.ibatis.session.SqlSessionFactoryBuilder;import com.forum.dao.UserMapper;import com.forum.po.User;/** * myBatis数据库连接测试 *  * @author db2admin *  */public class MyBatisTest {/** * 获得MyBatis SqlSessionFactory   * SqlSessionFactory负责创建SqlSession，一旦创建成功，就可以用SqlSession实例来执行映射语句，commit，rollback，close等方法。 * @return */private static SqlSessionFactory getSessionFactory() {SqlSessionFactory sessionFactory = null;String resource = "configuration.xml";try {sessionFactory = new SqlSessionFactoryBuilder().build(Resources.getResourceAsReader(resource));} catch (IOException e) {// TODO Auto-generated catch blocke.printStackTrace();}return sessionFactory;}public static void main(String[] args) {SqlSession sqlSession = getSessionFactory().openSession();UserMapper userMapper = sqlSession.getMapper(UserMapper.class);User user = userMapper.findById("1");System.out.println(user.getName());}}

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