1.問題

當(dāng)一個(gè)接口有2個(gè)不同實(shí)現(xiàn)時(shí),使用@Autowired注解時(shí)會(huì)報(bào)org.springframework.beans.factory.NoUniqueBeanDefinitionException異常信息

2.方案1-@Qualifier

使用Qualifier注解，選擇一個(gè)對(duì)象的名稱,通常比較常用

3. 方案2-@Primary

Primary可以理解為默認(rèn)優(yōu)先選擇,同時(shí)不可以同時(shí)設(shè)置多個(gè),
內(nèi)部實(shí)質(zhì)是設(shè)置BeanDefinition的primary屬性

示例

@Component("metalSinger") // 加注解，讓spring識(shí)別
public class MetalSinger implements Singer{

    @Override
    public String sing(String lyrics) {
        return "I am singing with DIO voice: "+lyrics;
    }
}

@Primary
@Component("operaSinger")
public class OperaSinger implements Singer {
    @Override
    public String sing(String lyrics) {
        return "I am singing in Bocelli voice: "+lyrics;
    }
}

public interface Singer {
    String sing(String lyrics);
}

@Component
public class SingerService {
    private static final Logger logger = LoggerFactory.getLogger(SingerService.class);
    @Autowired
    @Qualifier
    private Singer singer;
    public String sing(){
        return singer.sing("song lyrics");
    }

    public static void main(String[] args) {

        ApplicationContext context = new AnnotationConfigApplicationContext("context.annotation.primary");
        SingerService singerService = context.getBean(SingerService.class);
        System.out.println(singerService.sing());
    }

}

參考:
http://blog.csdn.net/qq_16055765/article/details/7883326