SpringBoot整合MyBatis_springboot整合mybatis配置文件

一、导包

<!--MySql-->
<dependency>
    <groupId>mysql</groupId>
    <artifactId>mysql-connector-java</artifactId>
    <version>5.1.49</version>
</dependency>
 
<!--Mybatis-->
<dependency>
    <groupId>org.mybatis.spring.boot</groupId>
    <artifactId>mybatis-spring-boot-starter</artifactId>
    <version>2.2.2</version>
</dependency>

二、配置文件

spring:
  datasource:
    driver-class-name: com.mysql.cj.jdbc.Driver
    url: jdbc:mysql://192.168.88.130:3306/ylb?useUnicode=true&characterEncoding=utf8&zeroDateTimeBehavior=convertToNull&useSSL=true&serverTimezone=GMT%2B8
    username: root
    password: root
 
# mybatis
mybatis:
  mapper-locations: classpath:/mapper/**/*.xml
  configuration:
    log-impl: org.apache.ibatis.logging.stdout.StdOutImpl
    map-underscore-to-camel-case: true # 驼峰命名

三、编写Mapper类：

@Mapper
// 也可以在启动类上加上@MapperScan(basePackages = "com.example.dataservice.mapper")注解
public interface UserMapper {
 
    Integer insert(User user);
 
    User findByUserName(String username);
 
    Integer updatePasswordById(User user);
 
    User findByUid(Integer uid);
 
    Integer updateInfoByUid(User user);
 
}

四、编写Mapper.XML文件:

<?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.cy.mapper.UserMapper">
 
    <resultMap id="UserEntityMap" type="com.cy.entity.User">
        <result column="uid" property="uid"></result>
        <result column="is_delete" property="isDelete"></result>
        <result column="created_user" property="createdUser"></result>
        <result column="created_time" property="createdTime"></result>
        <result column="modified_user" property="modifiedUser"></result>
        <result column="modified_time" property="modifiedTime"></result>
    </resultMap>
 
    <!--useGeneratedKeys 主键自增-->
    <!--keyProperty 指明主键-->
    <insert id="insert" useGeneratedKeys="true" keyProperty="uid">
        insert into t_user(username, password, salt, phone, email, gender, avatar, is_delete, created_user,
                           created_time, modified_user, modified_time)
        values (#{username}, #{password}, #{salt}, #{phone}, #{email}, #{gender}, #{avatar}, #{isDelete},
                #{createdUser},
                #{createdTime}, #{modifiedUser}, #{modifiedTime})
    </insert>
 
    <select id="findByUserName" resultMap="UserEntityMap">
        select *
        from t_user
        where username = #{username}
    </select>
 
    <update id="updatePasswordById">
        update t_user
        set password=#{password},
            modified_user=#{modifiedUser},
            modified_time=#{modifiedTime}
        where uid = #{uid}
    </update>
 
    <select id="findByUid" resultMap="UserEntityMap">
        select *
        from t_user
        where uid = #{uid}
    </select>
 
    <update id="updateInfoByUid">
        update t_user
        set
        <if test="phone!=null">phone=#{phone},</if>
        <if test="email!=null">email=#{email},</if>
        <if test="gender!=null">gender=#{gender},</if>
        modified_user=#{modifiedUser},
        modified_time=#{modifiedTime}
        where uid = #{uid}
    </update>
 
</mapper>

五、一些技巧

在MyBatis中多表查询的时候，一张表并不能存得下，我们的解决方案是new一个新的对象，我们称之为VO（Value Object）对象，这个对象专门用来存这次的联表查询；

MyBatis的Mapper.xml中的SQL语句整合<foreach>标签的案例：

# 指定实体类的路径
mybatis.type-aliases-package=com.example.entity