MyBatis学习总结[1]-入门

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文档地址http://www.mybatis.org/mybatis-3/zh/index.html

安装

要使用 MyBatis，只需将 mybatis-x.x.x.jar 文件置于 classpath 中即可。还要放所使用的数据库的驱动。
这里写图片描述

配置文件

<?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> <!--注意标签要按以下顺序来(properties?, settings?, typeAliases?, typeHandlers?,objectFactory?, objectWrapperFactory?, reflectorFactory?, plugins?, environments?, databaseIdProvider?, mappers?)-->   <!-- 别名 -->   <typeAliases>      <package name="me.model"/>  </typeAliases>  <environments default="development">    <environment id="development">      <!-- 配置事务管理 -->      <transactionManager type="JDBC"/>      <!-- 配置数据库连接信息 -->      <dataSource type="POOLED">        <property name="driver" value="com.mysql.jdbc.Driver"/>        <property name="url" value="jdbc:mysql://localhost:3306/mybatis"/>        <property name="username" value="root"/>        <property name="password" value="1234"/>      </dataSource>    </environment>     </environments>  <mappers>    <!-- 注册Mapper -->    <mapper resource="me/mapper/UserMapper.xml"/>    <!-- <package name="me.dao"/> -->  </mappers></configuration>

实体类

package me.model;import java.util.List;public class User {    private int id;    private String name;    private String age;    public int getId() {        return id;    }    public void setId(int id) {        this.id = id;    }    public String getName() {        return name;    }    public void setName(String name) {        this.name = name;    }    public String getAge() {        return age;    }    public void setAge(String age) {        this.age = age;    }    @Override    public String toString() {        // TODO Auto-generated method stub        return id+" "+name+" "+age+" ";    }}

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"><mapper namespace="me.dao.UserDao">  <select id="selectById" parameterType="int" resultType="User">    select * from users where id = #{id}  </select></mapper>

Service类

package me.service;import java.io.InputStream;import java.util.List;import me.model.User;import org.apache.ibatis.session.SqlSession;import org.apache.ibatis.session.SqlSessionFactory;import org.apache.ibatis.session.SqlSessionFactoryBuilder;public class UserService {//从 XML 中构建 SqlSessionFactory    String resource = "conf.xml";    InputStream is = UserService.class.getClassLoader().getResourceAsStream(            resource);    SqlSessionFactory sqlSessionFactory = new SqlSessionFactoryBuilder()            .build(is);    SqlSession session = sqlSessionFactory.openSession();    public void selectUserById(int id) {    //me.dao.UerDao.selectById为map文件的xml，namespace+select标签id        User user=session.selectOne("me.dao.UerDao.selectById",id);    }    public void close(){        session.close();    }}

测试类

package me.service;import static org.junit.Assert.*;import org.junit.AfterClass;import org.junit.BeforeClass;import org.junit.Test;public class UserServiceTest {    static UserService s=null;    @BeforeClass    public static void before(){        s=new UserService();    }    @Test    public void test() {        s.selectUserById(2);    }    @AfterClass    public static void after(){        s.close();    }}

结果

语句执行成功，另外这个日志是log4j输出的，配置方法点这里

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