MyBatis一级缓存的脏数据——MyBatis迷信者，清醒点之二

create database mybatis;
use mybatis;
-- 创建数据表
create table news_inf
(
 news_id integer primary key auto_increment,
 news_title varchar(255),
 news_content varchar(255)
);


insert into news_inf
values (null, '李刚的公众号', '大家可关注李刚老师的公众号：fkbooks');
insert into news_inf
values (null, 'Java 13来了', 'Java 13新增了块字符串，用起来更爽了');

<?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="org.crazyit.app.dao.NewsMapper">
    <!-- 为getNews方法定义SQL语句 -->
    <select id="getNews" resultType="news">
        select news_id id, news_title title,
        news_content content from news_inf
        where news_id=#{id}
    </select>
    <!-- 为updateNews方法定义SQL语句 -->
    <update id="updateNews">
        update news_inf
        set news_title=#{arg0}
        where news_id=#{arg1}
    </update>
</mapper>

public class NewsManager
{
    private static SqlSessionFactory sqlSessionFactory;
    public static void main(String[] args) throws Exception
{
        String resource = "mybatis-config.xml";
        // 使用Resources工具从类加载路径下加载指定文件
        InputStream inputStream = Resources.getResourceAsStream(resource);
        sqlSessionFactory = new SqlSessionFactoryBuilder()
            .build(inputStream);
        new Thread(NewsManager::update).start();   // ①
        cacheTest();   // ②
    }
    public static void cacheTest()
{
        SqlSession sqlSession = sqlSessionFactory.openSession();
        // 获取Mapper对象
        NewsMapper newsMapper = sqlSession.getMapper(NewsMapper.class);
        // 查询id为1的News对象，会执行select语句
        News news = newsMapper.getNews(1);
        System.out.println(news.getTitle());
        try
        {
            // 线程暂停10ms，是为了模拟让另外一条线程在此处获得CPU的情形
            Thread.sleep(10);
        }
        catch (Exception ex){}
        News news2 = newsMapper.getNews(1);
        System.out.println(news2.getTitle());
        // 提交事务
        sqlSession.commit();
        // 关闭资源
        sqlSession.close();
    }
    public static void update()
{
        SqlSession sqlSession = sqlSessionFactory.openSession();
        // 获取Mapper对象
        NewsMapper newsMapper = sqlSession.getMapper(NewsMapper.class);
        // 更新id为1的News对象
        newsMapper.updateNews("测试", 1);
        // 提交事务
        sqlSession.commit();
        // 关闭资源
        sqlSession.close();
    }
}

[java] DEBUG [main] org.crazyit.app.dao.NewsMapper.getNews ==>  Preparing: select news_id id, news_title title, news_content content from news_inf where news_id=?
[java] DEBUG [main] org.crazyit.app.dao.NewsMapper.getNews ==> Parameters: 1(Integer)
[java] 李刚的公众号
[java] DEBUG [Thread-0] org.crazyit.app.dao.NewsMapper.updateNews ==>  Preparing: update news_inf set news_title=? where news_id=?
[java] DEBUG [Thread-0] org.crazyit.app.dao.NewsMapper.updateNews ==> Parameters: 测试(String), 1(Integer)
[java] DEBUG [Thread-0] org.crazyit.app.dao.NewsMapper.updateNews <==    Updates: 1
[java] DEBUG [main] org.crazyit.app.dao.NewsMapper.getNews <==      Total: 1
[java] 李刚的公众号