代码之家 › 专栏 › 技术社区 › Deniss M.

Spring:@Service类和带有@Autowired(required=false)参数的构造函数:如何用这些参数初始化它?

spring java

Deniss M. · 技术社区 · 6 年前

我有一个要用构造函数参数的不同传入值动态初始化的服务类:

@Service
public 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;
    }

是否可以在运行时初始化 @Service @Autowired(required = false) 参数(在本例中是自己的url和密码)?这段代码看起来怎么样?

2 回复 | 直到 6 年前

Harry Cotte 5 年前

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);
  }
}

然后您可以使用这样的实例

@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
   } 
}

Reno 6 年前

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;
    }