第一

@Override
public Result<Boolean> register(RegisterBody registerBody) {
    if (sysUserService.checkUserExistByUserName(registerBody.getUsername())) {
        throw new SysException(SystemErrorCode.USERNAME_EXIST);
    }

    SysUser sysUser = buildSysUser(registerBody);

    boolean saved = sysUserService.save(sysUser);
    return Result.success(saved);
}