新公司spring代码疑问

Question

@Service
public class ZcDataJdServiceImpl extends ServiceImpl<ZcDataJdMapper, ZcDataJd> implements IZcDataJdService {

    private final ZcDataLogMapper zcDataLogMapper;

    private final ZcDataMapper zcDataMapper;

    private final SysUserRoleMapper sysUserRoleMapper;

    private final SysRoleMapper sysRoleMapper;

    @Autowired
    public ZcDataJdServiceImpl(ZcDataLogMapper zcDataLogMapper, ZcDataMapper zcDataMapper, SysUserRoleMapper sysUserRoleMapper, SysRoleMapper sysRoleMapper) {
        this.zcDataLogMapper = zcDataLogMapper;
        this.zcDataMapper = zcDataMapper;
        this.sysUserRoleMapper = sysUserRoleMapper;
        this.sysRoleMapper = sysRoleMapper;
    }
}

入职新公司，看项目代码，请问下这里要注入mapper 直接@resource 就好了 ，为啥要这样写，用构造方法，还用final修饰？

Answer 1

总体来说，字段注入和构造器注入的差别不大，毕竟都无法避免循环注入问题。
但@Resource 是java自带的注解，@Autowired 是spring的注解，@Autowired 使用场景更灵活。
使用final修饰可以避免mapper对象被二次赋值，不过我感觉可能是为了消除idea自动检测到的警告。