基础的mybatis学习

　　git：https://gitee.com/juncaoit/xdmybatis

一：普通的jdbc

1.添加pom

        
        <dependency>
            <groupId>org.springframework.bootgroupId>
            <artifactId>spring-boot-starter-jdbcartifactId>
        dependency>
        <dependency>
            <groupId>mysqlgroupId>
            <artifactId>mysql-connector-javaartifactId>
        dependency>

2.jdbc代码

package com.jun.basic.controller;

import com.fasterxml.jackson.core.JsonProcessingException;
import org.junit.Test;

import java.sql.*;

public class JdbcTest {
    /**
     * mysql的jdbc测试
     */
    @Test
    public void test1() throws ClassNotFoundException, SQLException, JsonProcessingException {
        Class.forName("com.mysql.cj.jdbc.Driver");
        String url = "jdbc:mysql://127.0.0.1:3306/center?useUnicode=true&characterEncoding=utf-8&useSSL=false&serverTimezone=GMT";
        String useName = "root";
        String pwd = "123456";
        Connection connection = DriverManager.getConnection(url, useName, pwd);
        Statement statement = connection.createStatement();
        ResultSet resultSet = statement.executeQuery("select  * from video");
        while (resultSet.next()) {
            System.out.println("resultSet=" + resultSet.getString("title"));
        }
        statement.close();
    }
}

二：简单原理

1.pom

        
            org.mybatis
            mybatis
            3.5.9

2.工作流程

3.添加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://127.0.0.1:3306/center?useUnicode=true&characterEncoding=utf-8&useSSL=false&serverTimezone=GMT"/>
                <property name="username" value="root"/>
                <property name="password" value="123456"/>
            dataSource>
        environment>
    environments>

    <mappers>
        <mapper resource="mapper/VideoMapper.xml"/>
    mappers>
configuration>

其中：VideoMapper.xml

存在resultType。

<?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">

其中，VideoMapper.class

package com.jun.xdmybatis.domain;

import com.jun.xdmybatis.dao.Video;
import org.apache.ibatis.annotations.Param;

public interface VideoMapper {
    Video selectById(@Param("id") int id);
}

4.使用

public class XdMybatis {
    public static void main(String[] args) throws IOException {
        String resource = "config/mybatis-config.xml";
        InputStream inputStream = Resources.getResourceAsStream(resource);
        SqlSessionFactory sqlSessionFactory = new SqlSessionFactoryBuilder().build(inputStream);
        try (SqlSession sqlSession = sqlSessionFactory.openSession()) {
            final VideoMapper mapper = sqlSession.getMapper(VideoMapper.class);
            final Video video = mapper.selectById(30);
            log.info("video={}", JsonUtils.toJsonString(video));
        } catch (Exception e) {
            e.printStackTrace();
        }
    }
}

5.入参的说明

　　paramterType的参数类型

　　　　可以是基本类型，如果是一个参数，可以不写，如果是两个，则不好写，也可以不写

　　　　可以是java集合

　　　　可以是对象

三：增删改查

1.表结构

CREATE TABLE `video` (
  `id` int(11) unsigned NOT NULL AUTO_INCREMENT,
  `title` varchar(524) DEFAULT NULL COMMENT '视频标题',
  `summary` varchar(1026) DEFAULT NULL COMMENT '概述',
  `cover_img` varchar(524) DEFAULT NULL COMMENT '封面图',
  `price` int(11) DEFAULT NULL COMMENT '价格,分',
  `create_time` datetime DEFAULT NULL COMMENT '创建时间',
  `point` double(11,2) DEFAULT '8.70' COMMENT '默认8.7，最高10分',
  PRIMARY KEY (`id`)
) ENGINE=InnoDB AUTO_INCREMENT=48 DEFAULT CHARSET=utf8;

2.java

package com.jun.xdmybatis;

import com.jun.xdmybatis.dao.Video;
import com.jun.xdmybatis.domain.VideoMapper;
import com.jun.xdmybatis.utils.JsonUtils;
import lombok.extern.slf4j.Slf4j;
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.springframework.boot.SpringApplication;
import org.springframework.boot.autoconfigure.SpringBootApplication;
import org.springframework.boot.autoconfigure.jdbc.DataSourceAutoConfiguration;

import java.io.IOException;
import java.io.InputStream;
import java.util.*;

/**
 * 主类
 */
//@SpringBootApplication(exclude = {DataSourceAutoConfiguration.class})
@Slf4j
public class XdMybatis {
    public static void main(String[] args) throws IOException {
        String resource = "config/mybatis-config.xml";
        InputStream inputStream = Resources.getResourceAsStream(resource);
        SqlSessionFactory sqlSessionFactory = new SqlSessionFactoryBuilder().build(inputStream);
        try (SqlSession sqlSession = sqlSessionFactory.openSession()) {
            final VideoMapper mapper = sqlSession.getMapper(VideoMapper.class);
            // 查询
            selectById(mapper);
            // 插入
            insert(mapper);
            // 批量插入
            batchInsert(mapper);
            // 更新
            update(mapper);
            // 动态更新
            updateVideoSelective(mapper);
            // 删除
            delete(mapper);
        } catch (Exception e) {
            e.printStackTrace();
        }
    }


    /**
     * 查询
     */
    private static void selectById(VideoMapper mapper) throws com.fasterxml.jackson.core.JsonProcessingException {
        final Video video = mapper.selectById(30);
        log.info("video={}", JsonUtils.toJsonString(video));
    }

    /**
     * 插入
     */
    private static void insert(VideoMapper mapper) {
        //新增一条记录
        Video video = new Video();
        video.setTitle("课堂面试专题900道");
        video.setCoverImg("xdclass.net/aaa.png");
        video.setPoint(9.4);
        video.setCreateTime(new Date());
        video.setPrice(9900);
        video.setSummary("这个是面试专题概要");

        int rows = mapper.add(video);
        System.out.println(rows);
    }

    /**
     * 批量插入
     */
    private static void batchInsert(VideoMapper mapper) {
        //新增一条记录
        Video video1 = new Video();
        video1.setTitle("小滴课堂面试专题900道1111");
        video1.setCoverImg("xdclass.net/aaa.png111");
        video1.setPoint(9.41);
        video1.setCreateTime(new Date());
        video1.setPrice(9911);
        video1.setSummary("这个是面试专题概要11");

        //新增一条记录
        Video video2 = new Video();
        video2.setTitle("小滴课堂面试专题900道2");
        video2.setCoverImg("xdclass.net/aaa.png2");
        video2.setPoint(9.2);
        video2.setCreateTime(new Date());
        video2.setPrice(9922);
        video2.setSummary("这个是面试专题概要22");

        List

3.sql

<?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">


    


    
            keyColumn="id">
        INSERT INTO `video` ( `title`, `summary`, `cover_img`, `price`, `create_time`, `point`)
        VALUES
        (#{title,jdbcType=VARCHAR},#{summary,jdbcType=VARCHAR},#{coverImg,jdbcType=VARCHAR},#{price,jdbcType=INTEGER},
         #{createTime,jdbcType=TIMESTAMP},#{point,jdbcType=DOUBLE});
    


    
    
        INSERT INTO `video` ( `title`, `summary`, `cover_img`, `price`, `create_time`, `point`)
        VALUES
        
            (#{video.title,jdbcType=VARCHAR},#{video.summary,jdbcType=VARCHAR},#{video.coverImg,jdbcType=VARCHAR},
            #{video.price,jdbcType=INTEGER},
            #{video.createTime,jdbcType=TIMESTAMP},#{video.point,jdbcType=DOUBLE})
        
    

    
        update video
        set
        title = #{title,jdbcType=VARCHAR},
        summary = #{summary,jdbcType=VARCHAR},
        cover_img = #{coverImg,jdbcType=VARCHAR},
        price = #{price,jdbcType=INTEGER},
        create_time = #{createTime,jdbcType=TIMESTAMP},
        point = #{point,jdbcType=DOUBLE}
        where
        id = #{id}
    

    
        update video
        
            <if test="title != null "> title = #{title,jdbcType=VARCHAR},if>
            <if test="summary != null "> summary = #{summary,jdbcType=VARCHAR},if>
            <if test="coverImg != null "> cover_img = #{coverImg,jdbcType=VARCHAR},if>
            <if test="price != 0 "> price = #{price,jdbcType=INTEGER},if>
            <if test="createTime !=null "> create_time = #{createTime,jdbcType=TIMESTAMP},if>
            
            <if test="point != null "> point = #{point,jdbcType=DOUBLE},if>
        
        where
        id = #{id}

    


    
    
        delete from video where create_time  ]]> #{createTime} and price = ]]> #{price}

mybatis

基础的mybatis学习

git：https://gitee.com/juncaoit/xdmybatis

一：普通的jdbc

二：简单原理

三：增删改查

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