Spring：带有@Autowired(required = false) 参数的构造函数的

Question

我有一个服务类，我想用构造函数参数的不同传入值动态初始化它：@Servicepublic class SomeServiceImpl implements SomeService {    private final SomeProperties someProperties;    private final String url;    private final String password;    private final Logger log = LoggerFactory.getLogger(SomeServiceImpl.class);    @Autowired    public SomeServiceImpl(SomeProperties someProperties,                             @Autowired(required = false) String url,                             @Autowired(required = false) String password) {        this.someProperties = someProperties;        this.url = url;        this.password = password;    }是否可以在运行时@Service使用自己提供的@Autowired(required = false)参数（在本例中为自己的 url 和密码）在另一个 spring 组件类中对其进行初始化？这段代码会是什么样子？

Answer 1

你可以这样做

@Configuration

class SomeConfigClass {

    @Autowired

    SomeProperties someProperties

    @Value("${url1}")

    String url1

    @Value("${password1}")

    String password1

    ..............

     // Do this for other url's and properties or check out @ConfigurationProperties

    ..............

    @Bean("someService1")

    public SomeService() {

        return new SomeService(someProperties, url1, password1);

    }

    @Bean("someService2")

    public SomeService() {

        return new SomeService(someProperties, url2, password2);

    }

    ...............

    ..............

}

创建工厂类

@Configuration //typo corrected

class SomeServiceFactory {

  @Autowired // Spring will Autowire all instances of SomeService with bean name as key

  Map<String, SomeService> someServiceMap;

  public SomeService getSomeServiceByName(String name) {

    return someServiceMap.get(name);

  }

}

然后你可以像这样使用实例

@RestController

class SomeController {

    @Autowired

    SomeServiceFactory someServiceFactory;

    public void someEndpoint() {

     SomeService someService1 = SomeServiceFactory.getSomeServiceByName("someService1"); //You need to decide what argument to pass based on condition

     someService1.someFunction(...); // this will have url1 and password1

   } 

}

Answer 2

用户名和密码从何而来？也许您可以简单地从构造函数中删除它们并使用 @Value 注释从属性文件中读取值？

@Service

public class SomeServiceImpl implements SomeService {

    private final SomeProperties someProperties;

    @Value("${service.url}")

    private String url;

    @Value("${service.password}")

    private String password;

    private final Logger log = LoggerFactory.getLogger(SomeServiceImpl.class);

    @Autowired

    public SomeServiceImpl(SomeProperties someProperties) {

        this.someProperties = someProperties;

    }