Mybatis xml配置文件的增删改查初学

代码结构

image.png

Animal为实体类，Main测试方法
Main.java

package com.ly3;

import com.ly3.entity.Animal;
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 java.io.IOException;
import java.io.InputStream;
import java.util.HashMap;
import java.util.Map;
import java.util.Properties;
import java.util.Random;

public class Main {
    public static void main(String[] args) throws IOException {
        Properties properties=new Properties();
        //加载配置文件
        properties.load(Resources.getResourceAsStream("mappings3/sql2.properties"));
        InputStream inputStream= Resources.getResourceAsStream("mappings3/mybatis-config-noresource.xml");
        //创建一个SqlSessionFactory
        SqlSessionFactory sqlSessionFactory=new SqlSessionFactoryBuilder().build(inputStream,properties);
        try(SqlSession sqlSession=sqlSessionFactory.openSession()) {
            Animal animal1=new Animal();
            int id=new Random().nextInt(1000000);
            animal1.setAgeMax("14");
            animal1.setType("兔子");
            //使用xml的数据新增
            sqlSession.insert("com.ly3.entity.AnimalMapper.insertAnimal", animal1);
            animal1.setType(animal1.getType()+"[我被改了]");
            //数据修改
            sqlSession.update("com.ly3.entity.AnimalMapper.updateAnimal",animal1);
            //数据查询
            Animal animal=sqlSession.selectOne("com.ly3.entity.AnimalMapper.selectAnimal",animal1.getId());
            Map<String,Integer> map=new HashMap<>();
            map.put("id",animal1.getId()-1);
            //数据删除
            sqlSession.delete("com.ly3.entity.AnimalMapper.deleteAnimal",map);
            System.out.println(animal);
            //注意这里，增删改都是需要commit才会生效
            sqlSession.commit();
        }
    }
}

mybatis-config-noresource.xml文件

<?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>
    <settings>
        <setting name="mapUnderscoreToCamelCase" value="true"/>
    </settings>
    <environments default="dv">
        <environment id="dv">
            <transactionManager type="JDBC"/>
            <dataSource type="POOLED">
                <property name="url" value="${url}"/>
                <property name="driver" value="${driver}"/>
                <property name="username" value="${username}"/>
                <property name="password" value="${password}"/>
            </dataSource>
        </environment>
    </environments>

    <mappers>
        <mapper resource="mappings3/com/ly3/entity/AnimalMapper.xml" />
    </mappers>
</configuration>

配置文件sql2.properties

url=jdbc:mysql://localhost:3306/test1
driver=com.mysql.cj.jdbc.Driver
username=root
password=test.lwm

AnimalMapper.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.ly3.entity.AnimalMapper">
    <select id="selectAnimal" parameterType="int" resultType="com.ly3.entity.Animal">
        SELECT * FROM animal where id = #{id}
    </select>
    <insert id="insertAnimal" useGeneratedKeys="true" keyColumn="id" keyProperty="id">
        insert into animal(`type`,age_max) values(#{type},#{ageMax})
    </insert>
    <update id="updateAnimal">
        update animal set type = #{type} , age_max = #{ageMax} where id = #{id}
    </update>
    <delete id="deleteAnimal">
        delete from animal where id = #{id}
    </delete>
</mapper>