@Transactional 本地事务提交

@Override
@Transactional
public void testTransactional1() {
    Dict dict=baseMapper.selectOne(new QueryWrapper().eq("d_code", "AAA"));
    dict.setDValue("2");
    baseMapper.updateById(dict);
    try {
        Thread.sleep(10000); // 10 s
    } catch (InterruptedException e) {
        e.printStackTrace();
    }

    Dict dictSS=baseMapper.selectOne(new QueryWrapper().eq("d_code", "AAA"));

    System.out.println("dictSS="+ JSON.toJSonString(dict));
    System.out.println("testTransactional1");
 }

@Override
@Transactional
public void testTransactional2() {
    Dict dict=baseMapper.selectOne(new QueryWrapper().eq("d_code", "AAA"));
    System.out.println("dict="+ JSON.toJSonString(dict));
}

Executor threadPool = Executors.newFixedThreadPool(5);
    threadPool.execute(new Runnable() {
        public void run() {
            dictService.testTransactional1();

        }
    });

threadPool.execute(new Runnable() {
    public void run() {
        dictService.testTransactional2();
    }
});

输出:dict={"createTime":"2021-09-29 10:59:18","dCode":"AAA","dDesc":"测试","dType":1,"dValue":"1","did":5,"updateTime":"2021-09-29 10:59:18"}

dictSS={"createTime":"2021-09-29 10:59:18","dCode":"AAA","dDesc":"测试","dType":1,"dValue":"2","did":5,"updateTime":"2021-09-29 10:59:18"}

总结：操作同一行数据时,同一事务机制下，读取的是预提交的行数据；不同事务读取的是默认机制 iIsolation.REPEATABLE_READ(可重复读)