Spring实现一个接口多个实现自动注入

最近项目遇到了一个问题，Spring一个接口怎么多实现？方法有很多，总结了下，有两种方法：

1. @Primary注解指定一个主的实现，使用@Autowired就能实现自动注入

需要实现的接口

public interface HelloService {
    public BizPo sayHi(String id);
}

接口实现1

@Service
@Primary
public class HelloHangZhouServiceImpl implements HelloService {

    @Override
    public BizPo sayHi(String id) {
        System.out.println(list);
        if (id.equals("1")) {
            System.out.println("数据源1");
        } else if (id.equals("2")) {
            System.out.println("数据源2");
        }
        System.out.println("默认数据源");
        return new BizPo(id,"hangzhou");
    }
}

接口实现2

@Service
public class HelloGuangZhouServiceImpl implements HelloService {
    @Override
    public BizPo sayHi(String id) {
        return new BizPo(id,"guangzhou");
    }
}

Controller层

@RestController
public class HelloController {
	//这里会自动注入加了@Primary注解的那个接口实现类
    @Autowired
    private HelloService helloService;
    
    //自动注入实现了HelloService接口的实现类
    @Autowired
    private List<HelloService> list;
    
    @GetMapping("/{id}")
    public @ResponseBody BizPo getById(@PathVariable String id){
        System.out.println("id ==> "+id);
        BizPo b = helloService.sayHi(id);
        System.out.println(b);
        return b;
    }
}

想要拿到所有的接口实现类怎么办？可以通过下面这个方式。

	@Autowired
    private List<HelloService> list;

那么如果我想拿到某个指定的bean怎么办？看方法2

2. @Service（“XXXX”）命名实现的名称+@Qualifier(“helloGuangZhouService”)&&@Resource指定需要注入的bean。

接口

public interface HelloService {
    public BizPo sayHi(String id);
}

实现1

@Service("helloGuangZhouService")
public class HelloGuangZhouServiceImpl implements HelloService {
    @Override
    public BizPo sayHi(String id) {
        return new BizPo(id,"guangzhou");
    }
}

实现2

@Service("helloHangZhouService")
public class HelloHangZhouServiceImpl implements HelloService {

    @Override
    public BizPo sayHi(String id) {
        System.out.println(list);
        if (id.equals("1")) {
            System.out.println("数据源1");
        } else if (id.equals("2")) {
            System.out.println("数据源2");
        }
        System.out.println("默认数据源");
        return new BizPo(id,"hangzhou");
    }
}

controller

@RestController
public class HelloController {

    @Qualifier("helloGuangZhouService")
    @Resource
    private HelloService guangzhouservice;

    @Qualifier("helloHangZhouService")
    @Resource
    private HelloService hangzhouservice;
    
    @GetMapping("/{id}")
    public @ResponseBody BizPo getById(@PathVariable String id){
        System.out.println("id ==> "+id);
        BizPo b = guangzhouservice.sayHi(id);
        System.out.println(b);
        return b;
    }
}