resultMap1_自定义结果映射规则

1、项目结构

2、Employee.java

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;
    }
    @Override
    public 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
    }
    
    
}

3、EmployeeMapperPlus.java

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);
    
}

4、MybatisTest.java

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);
    }
    
    
    @Test
    public 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();
        }
    }
    
}

5、EmployeeMapperPlus.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="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>

   ①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
②定义普通列封装规则 ，其他不指定的列会自动封装

6、log4j.xml

<?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>

7、mybatis-config.xml

<?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.xml
            url:引用网络路径或磁盘下的sql映射文件
                    file:///var/mappers/AuthorMapper.xml
            class：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>