mbatis 入门

   https://mybatis.org/mybatis-3/zh/index.html#

 idea创建一个Maven工程

设置时间

北京时间 GMT%2B8 ，  默认是UTC    -全球时间

1.

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"/>
            <dataSource type="POOLED">
                <property name="driver" value="com.mysql.cj.jdbc.Driver"/>
                <property name="url" value="jdbc:mysql://localhost:3306/world?useUnicode=true&amp;characterEncoding=utf-8&amp;useSSL=false&amp;serverTimezone=GMT%2B8"/>
                <property name="username" value="root"/>
                <property name="password" value="xxx"/>
            </dataSource>
        </environment>
    </environments>
    <mappers>
        <mapper resource="CityMapper.xml"/>
    </mappers>
</configuration>

2.创建实体类

City

package com.ceshi.entity;

//实体类
public class City {
    private int id;
    private String Name;
    private String Country;
    private String District;

    public int getId() {
        return id;
    }

    public void setId(int id) {
        this.id = id;
    }

    public String getName() {
        return Name;
    }

    public void setName(String name) {
        Name = name;
    }

    public String getCountry() {
        return Country;
    }

    public void setCountry(String country) {
        Country = country;
    }

    public String getDistrict() {
        return District;
    }

    public void setDistrict(String district) {
        District = district;
    }

    public int getPopulation() {
        return Population;
    }

    public void setPopulation(int population) {
        Population = population;
    }

    private int Population;
}

3.创建接口

CityMapper

package com.ceshi.mapper;

import com.ceshi.entity.City;

import java.util.List;

//映射器类
public interface CityMapper {
       List<City> selectCity();
}

4.创建映射文件

CityMapper.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.ceshi.mapper.CityMapper">
    <select id="selectCity" resultType="com.ceshi.entity.City">
    select * from city
  </select>
</mapper>