普通项目使用mybatis

<!--在主键是自增的情况下使用keyProperty="id" useGeneratedKeys="true"，添加成功后可以直接使用主键值，其中keyProperty的值是对象的属性值，而不是数据库表中的字段名-->
<insert id="insertSelective" parameterType="com.xxx.entity.UserEntity" keyProperty="id" useGeneratedKeys="true">
....
</insert>

pom.xml

<?xml version="1.0" encoding="UTF-8"?>
<project xmlns="http://maven.apache.org/POM/4.0.0"
         xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
         xsi:schemaLocation="http://maven.apache.org/POM/4.0.0 http://maven.apache.org/xsd/maven-4.0.0.xsd">
    <modelVersion>4.0.0</modelVersion>

    <groupId>com.zsk</groupId>
    <artifactId>mybatis-normal-demo</artifactId>
    <version>1.0-SNAPSHOT</version>
    <dependencies>
        <dependency>
            <groupId>org.mybatis</groupId>
            <artifactId>mybatis</artifactId>
            <version>3.4.5</version>
        </dependency>
        <dependency>
            <groupId>mysql</groupId>
            <artifactId>mysql-connector-java</artifactId>
            <version>8.0.22</version>
        </dependency>
        <dependency>
            <groupId>junit</groupId>
            <artifactId>junit</artifactId>
            <version>4.12</version>
            <scope>test</scope>
        </dependency>
    </dependencies>
</project>

jdbc.properties

db.driver=com.mysql.cj.jdbc.Driver
db.url=jdbc:mysql://127.0.0.1:3306/test_db?useUnicode=true&characterEncoding=utf8&useSSL=false&serverTimezone=Asia/Shanghai
db.username=root
db.password=root

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>
    <!--引入jdbc.propeties文件-->
    <properties resource="jdbc.properties"/>
    <settings>
        <!-- 驼峰映射 -->
        <setting name="mapUnderscoreToCamelCase" value="true" />
    </settings>
    <environments default="development">
        <!-- environment:某一个环境 id:就是这个环境的名称-->
        <environment id="development">
            <!--
                transactionManager:事务管理(ACID)
                    type="JDBC|MANAGED" jdbc:简单jdbc事务 MANAGED：啥都不做
            -->
            <transactionManager type="JDBC"/>
            <!-- 数据源(连接池) POOLED:mybatis内置的连接池 -->
            <dataSource type="POOLED">
                <!--驱动,地址,用户名,密码-->
                <property name="driver" value="${db.driver}"/>
                <property name="url" value="${db.url}"/>
                <property name="username" value="${db.username}"/>
                <property name="password" value="${db.password}"/>
            </dataSource>
        </environment>
    </environments>
    <mappers>
        <!--配置映射xml-->
        <mapper resource="com/zsk/IAttrInfoIDao.xml"/>
    </mappers>
</configuration>

dao/mapper.java

package com.zsk.dao;

import com.zsk.entity.AttrInfo;
import org.apache.ibatis.annotations.Param;

import java.util.List;

public interface IAttrInfoIDao {
    int deleteByPrimaryKey(Long id);

    int insert(AttrInfo record);

    int insertSelective(AttrInfo record);

    AttrInfo selectByPrimaryKey(Long id);

    int updateByPrimaryKeySelective(AttrInfo record);

    int updateByPrimaryKey(AttrInfo record);

    int batchInsert(List<AttrInfo> list);

    List<AttrInfo> findByName(@Param("name") String name);

    int deleteByName(@Param("name") String name);

    boolean existByName(@Param("name") String name);
}

dao/mapper.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.zsk.dao.IAttrInfoIDao">
    <resultMap id="BaseResultMap" type="com.zsk.entity.AttrInfo">
        <id column="id" jdbcType="BIGINT" property="id"/>
        <result column="name" jdbcType="VARCHAR" property="name"/>
        <result column="value" jdbcType="BIGINT" property="value"/>
        <result column="create_time" jdbcType="TIMESTAMP" property="createTime"/>
        <result column="update_time" jdbcType="TIMESTAMP" property="updateTime"/>
    </resultMap>
    <sql id="Base_Column_List">
    id, `name`, `value`, create_time, update_time
    </sql>
    <select id="selectByPrimaryKey" parameterType="java.lang.Long" resultMap="BaseResultMap">
        select
        <include refid="Base_Column_List"/>
        from attr_info
        where id = #{id,jdbcType=BIGINT}
    </select>

    <delete id="deleteByPrimaryKey" parameterType="java.lang.Long">
    delete from attr_info
    where id = #{id,jdbcType=BIGINT}
  </delete>
    <insert id="insert" keyColumn="id" keyProperty="id" parameterType="com.zsk.entity.AttrInfo" useGeneratedKeys="true">
    insert into attr_info (`name`, `value`, create_time, 
      update_time)
    values (#{name,jdbcType=VARCHAR}, #{value,jdbcType=BIGINT}, #{createTime,jdbcType=TIMESTAMP}, 
      #{updateTime,jdbcType=TIMESTAMP})
  </insert>
    <insert id="insertSelective" keyColumn="id" keyProperty="id" parameterType="com.zsk.entity.AttrInfo"
            useGeneratedKeys="true">
        insert into attr_info
        <trim prefix="(" suffix=")" suffixOverrides=",">
            <if test="name != null">
                `name`,
            </if>
            <if test="value != null">
                `value`,
            </if>
            <if test="createTime != null">
                create_time,
            </if>
            <if test="updateTime != null">
                update_time,
            </if>
        </trim>
        <trim prefix="values (" suffix=")" suffixOverrides=",">
            <if test="name != null">
                #{name,jdbcType=VARCHAR},
            </if>
            <if test="value != null">
                #{value,jdbcType=BIGINT},
            </if>
            <if test="createTime != null">
                #{createTime,jdbcType=TIMESTAMP},
            </if>
            <if test="updateTime != null">
                #{updateTime,jdbcType=TIMESTAMP},
            </if>
        </trim>
    </insert>
    <update id="updateByPrimaryKeySelective" parameterType="com.zsk.entity.AttrInfo">
        update attr_info
        <set>
            <if test="name != null">
                `name` = #{name,jdbcType=VARCHAR},
            </if>
            <if test="value != null">
                `value` = #{value,jdbcType=BIGINT},
            </if>
            <if test="createTime != null">
                create_time = #{createTime,jdbcType=TIMESTAMP},
            </if>
            <if test="updateTime != null">
                update_time = #{updateTime,jdbcType=TIMESTAMP},
            </if>
        </set>
        where id = #{id,jdbcType=BIGINT}
    </update>
    <update id="updateByPrimaryKey" parameterType="com.zsk.entity.AttrInfo">
        update attr_info
        set `name` = #{name,jdbcType=VARCHAR},
          `value` = #{value,jdbcType=BIGINT},
          create_time = #{createTime,jdbcType=TIMESTAMP},
          update_time = #{updateTime,jdbcType=TIMESTAMP}
        where id = #{id,jdbcType=BIGINT}
    </update>
    <insert id="batchInsert" parameterType="java.util.List">
        insert into attr_info (`name`, `value`,`id`, create_time, update_time)
        values
        <foreach collection="list" item="item" separator=",">
            (
            #{item.name},
            #{item.value},
            <include refid="common_col_class"/>
            )
        </foreach>
    </insert>

    <sql id="common_col">
        id, create_time, update_time
    </sql>

    <sql id="common_col_class">
        #{item.id}, #{item.createTime},#{item.updateTime}
    </sql>

    <select id="findByName" resultType="com.zsk.entity.AttrInfo">
        select
        name,value,
        <include refid="common_col"/>
        from attr_info where `name` = #{name}
    </select>

    <delete id="deleteByName">
        delete  from attr_info where `name` = #{name}
    </delete>
    <select id="existByName" resultType="boolean">
       SELECT (SELECT COUNT(id) FROM attr_info WHERE name = #{name})>0 as res
    </select>
</mapper>

使用

// 加载 mybatis 全局配置文件
InputStream inputStream = this.getClass().getClassLoader().getResourceAsStream("mybatis-config.xml");
// 构建sqlSession的工厂
SqlSessionFactory sessionFactory = new SqlSessionFactoryBuilder().build(inputStream);
// 根据 sqlSessionFactory 产生 session
SqlSession session = sessionFactory.openSession();
IAttrInfoIDao attrDao = session.getMapper(IAttrInfoIDao.class);

// 如果是insert/update需要提交
session.commit();
session.close();