Spring ioc 注入规范化与优化

[Zsnd]

public class DataReportingServiceImpl implements DataReportingService {
    @Autowired
    private DivisionReportMapper divisionReportMapper;
    @Autowired
    private DivisionReportProgressMapper divisionReportProgressMapper;
    @Autowired
    private ReportMapper reportMapper;
    @Autowired
    private ReportProgressMapper reportProgressMapper;
    @Autowired
    private DivisionService divisionService;
    @Autowired
    private CurrentMonthService currentMonthService;

    //some code
}

可简化为：

import lombok.RequiredArgsConstructor;
@RequiredArgsConstructor
public class DataReportingServiceImpl implements DataReportingService {
    private final @NonNull DivisionReportMapper divisionReportMapper;
    private final @NonNull DivisionReportProgressMapper divisionReportProgressMapper;
    private final @NonNull ReportMapper reportMapper;
    private final @NonNull ReportProgressMapper reportProgressMapper;
    private final @NonNull DivisionService divisionService;
    private final @NonNull CurrentMonthService currentMonthService;

    //some code
}

构造函数注入的优点：

• 语义直观，不会造成客户端的疑惑
• 方便测试
• 提高安全性
• 采用 lombok 显著减少模板代码

• http://olivergierke.de/2013/11/why-field-injection-is-evil/
• https://docs.spring.io/spring/docs/current/spring-framework-reference/htmlsingle/#beans-autowired-annotation

[kid1412621]

https://www.baeldung.com/spring-injection-lombok

[kid1412621]

想我问下 lombok 生成的构造方法是怎么加上 @Autowired 注解的? 还是说是不用加? 懂了, If a bean has one constructor, you can omit the @Autowired .

[kid1412621]

还有, 需要使用 @Qualifier 的时候这种方式适用吗?

[kid1412621]

还有就是相互依赖的时候

[Zsnd]

不行，上述方式本质上只是针对构造函数注入的一种简化形式，不能替代属性注入。