今天写代码的时候有一个service需要用到事务，故使用@Transactional注解

@Transactional
Map<String, Object> joinTeam(Long teamId, Long userId) throws Exception;

这里抛出自己定义的异常来实现事务回滚

接口实现类方法如下

 public Map<String, Object> joinTeam(Long teamId, Long userId) throws Exception {Map<String, Object> result = new HashMap<>();Team team = teamService.getTeamById(teamId);//添加组队成员TeamMember member = new TeamMember();member.setUserId(userId);member.setTeamId(teamId);teamMemberDao.saveTeamMember(member);//更新组队人数team.setCurrentSignup(team.getCurrentSignup() + 1);Long count = teamService.updateTeamCurrentSignup(team);int i = 0;while (count == 0) {if (i >= 3) {throw new BaseException(BaseException.OPTIMISTIC_LOCK);}team = teamService.getTeamById(teamId);team.setCurrentSignup(team.getCurrentSignup() + 1);count = teamService.updateTeamCurrentSignup(team);i++;}result.put("success", true);result.put("message", "加入成功!");throw new Exception(BaseException.OPTIMISTIC_LOCK);}

teamMemberDao.saveTeamMember(member) 与 count = teamService.updateTeamCurrentSignup(team) 两个修改库操作，需要 teamService.updateTeamCurrentSignup(team) 抛异常来控制 teamMemberDao.saveTeamMember(member) 的数据回滚

但是结尾抛异常数据并不回滚，很是糟心。

于是查看Spring的Transactional的API文档，发现下面这段：

If no rules are relevant to the exception, it will be treated like DefaultTransactionAttribute (rolling back onruntime exceptions).

所以Transactional默认异常回滚是runtimeexcetion才回滚

excetion是所有异常的总称。
而runtimeexcetion是具体的某一个异常。

所以得将Transactional设置回滚异常为excetion

故将接口修改如下，这次再抛自定义异常就会回滚了

@Transactional(readOnly = false, propagation = Propagation.REQUIRED, rollbackFor = Exception.class)
Map<String, Object> joinTeam(Long teamId, Long userId) throws Exception;

• 1 天