package com.atguigu.mybatis.bean;public class Employee {private Integer id;private String lastName;private String email;private String gender;public Integer getId() {return id;}public void setId(Integer id) {this.id = id;}public String getLastName() {return lastName;}public void setLastName(String lastName) {this.lastName = lastName;}public String getEmail() {return email;}public void setEmail(String email) {this.email = email;}public String getGender() {return gender;}public void setGender(String gender) {this.gender = gender;}@Overridepublic String toString() {return "Employee [id=" + id + ", lastName=" + lastName + ", email=" + email + ", gender=" + gender + "]";}public Employee(Integer id, String lastName, String email, String gender) {super();this.id = id;this.lastName = lastName;this.email = email;this.gender = gender;}public Employee() {super();// TODO Auto-generated constructor stub
    }}

package com.atguigu.mybatis.dao;import java.util.List;
import java.util.Map;import org.apache.ibatis.annotations.MapKey;import com.atguigu.mybatis.bean.Employee;public interface EmployeeMapperPlus {public Employee getEmpById(Integer id);}

package com.atguigu.mybatis.test;import java.io.IOException;
import java.io.InputStream;
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 org.junit.Test;import com.atguigu.mybatis.bean.Employee;
import com.atguigu.mybatis.dao.EmployeeMapperPlus;public class MybatisTest {private SqlSessionFactory getSqlSessionFactory() throws IOException {String resource = "mybatis-config.xml";InputStream inputStream = Resources.getResourceAsStream(resource);return new SqlSessionFactoryBuilder().build(inputStream);}@Testpublic void test05() throws IOException {SqlSessionFactory sqlSessionFactory =getSqlSessionFactory();//1、获取到的SqlSession不会自动提交SqlSession openSession= sqlSessionFactory.openSession();try {/*2.获取接口的实现对象*/EmployeeMapperPlus mapper= openSession.getMapper(EmployeeMapperPlus.class);Employee employee=mapper.getEmpById(1);System.out.println(employee);//3、手动提交
            openSession.commit();} finally {openSession.close();}}}

<?xml version="1.0" encoding="UTF-8" ?>
<!DOCTYPE mapperPUBLIC "-//mybatis.org//DTD Mapper 3.0//EN""http://mybatis.org/dtd/mybatis-3-mapper.dtd">
<mapper namespace="com.atguigu.mybatis.dao.EmployeeMapperPlus"><resultMap type="com.atguigu.mybatis.bean.Employee" id="MyEmp"><!-- 指定主键的封装规则id可以放在result标签内，自定义主键对底层有优化column：指定哪一行property：指定对应的javabean属性--><id column="id" property="id"/><!-- 定义普通列封装规则 ，其他不指定的列会自动封装--><result column="last_name" property="lastName"/></resultMap><!-- public Employee getEmpById(Integer id); --><select id="getEmpById" resultMap="MyEmp">select * from tbl_employee where id=#{id}</select>
</mapper>

<?xml version="1.0" encoding="UTF-8" ?>
<!DOCTYPE log4j:configuration SYSTEM "log4j.dtd">
<log4j:configuration xmlns:log4j="http://jakarta.apache.org/log4j/"><appender name="STDOUT" class="org.apache.log4j.ConsoleAppender"><layout class="org.apache.log4j.PatternLayout"><param name="ConversionPattern" value="%-5p %d{MM-dd HH:mm:ss,SSS} %m (%F:%L) \n" /></layout></appender><logger name="java.sql"><level value="debug" /></logger><logger name="org.apache.ibatis"><level value="debug" /></logger><root><level value="debug" /><appender-ref ref="STDOUT" /></root>
</log4j:configuration>

<?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><environments default="development"><environment id="development"><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="111111" /></dataSource></environment></environments><mappers><!-- 注册userMapper.xml文件， resoure:引用类路径下的sql映射文件 mybatis/mapper/EmployeeMapper.xmlurl:引用网络路径或磁盘下的sql映射文件file:///var/mappers/AuthorMapper.xmlclass：引用注册接口①、有sql配置文件：映射文件名必须和接口同名，并且放在与接口同一目录下②、没有sql映射文件：所有的sql都是利用注解写在接口上③、推荐：比较重要的，复杂的Dao接口，写sql映射文件，便于维护不重要，简单的Dao接口为了开发快速可以写注解package：用于有sql映射文件的接口注册<package name="com.atguigu.mybatis.dao"/>--><mapper resource="com/atguigu/mybatis/dao/EmployeeMapperPlus.xml"/><!-- <package name="com.atguigu.mybatis.dao"/> --></mappers> </configuration>