Spring Boot 事务隔离级别READ_UNCOMMITTED不起作用

问：

我正在尝试在 spring boot 项目的 REST API 中实现隔离级别READ_UNCOMMITTED。以下是控制器和服务。

工单Con.java

@RestController
@RequestMapping("/ticket/book/")
public class TicketCon {
    @Autowired
    private TicketSer ticketSer;
 
    @PostMapping("/1")
    public ResponseEntity<?> bookTicket1(@RequestBody TicketRequestDto ticketRequestDto) throws InterruptedException {
        ticketSer.bookTicket1(ticketRequestDto.getShowSeats());
        return ResponseEntity.ok("");
    }
 
    @PostMapping("/2")
    public ResponseEntity<?> bookTicket2(@RequestBody TicketRequestDto ticketRequestDto) throws InterruptedException {
        ticketSer.bookTicket2(ticketRequestDto.getShowSeats());
        return ResponseEntity.ok("");
    }
}

售票服务.java

@Service
public class TicketSer {
    @Autowired
    private ShowSeatRepository showSeatRepository;
 
    @Transactional(isolation = Isolation.READ_UNCOMMITTED)
    public void bookTicket1(List<Long> showSeatsIds) throws InterruptedException {
        System.out.println("Reading Show Seats.");
        List<ShowSeat> showSeats = showSeatRepository.findAllByIdIn(showSeatsIds);
        showSeats.forEach(System.out::println);
 
        showSeats.forEach(s -> s.setShowSeatStatus(ShowSeatStatus.LOCKED));
        showSeatRepository.saveAll(showSeats);
        System.out.println("Show Seats LOCKED. Not Committed yet.");
        
        Thread.sleep(20000);
        System.out.println("Show Seats LOCKED. Will be Committed.");
    }
 
    @Transactional(isolation = Isolation.READ_UNCOMMITTED)
    public void bookTicket2(List<Long> showSeatsIds) throws InterruptedException {
        System.out.println("Reading Show Seats.");
        List<ShowSeat> showSeats = showSeatRepository.findAllByIdIn(showSeatsIds);
        showSeats.forEach(System.out::println);
    }
}

最初，所有 ShowSeat 实体的数据库中都有 ShowSeatStatus=“AVAILABLE”。

首先，我正在执行 ticket/book/1 API，这将使所有传递的 showSeatsIds 的 ShowSeatStatus=“LOCKED” 进入睡眠状态 20 秒，而无需在数据库中提交。

然后，在 5 秒后（在第一个事务提交之前），我正在执行 ticket/book/2 API，它正在读取传递的相同 showSeatsIds。

我希望第二个 API 的输出将传递的 showSeatIds 的 ShowSeatStatus 打印为“LOCKED”，因为这是脏读（未提交）数据。但这并没有发生。我看到这些showSeatIds的输出为“AVAILABLE”。

我哪里错了？ 请帮忙。