【教程】微服务使用Feign接口进行远程调用的步骤

Sample

以 finance 模块调用 exchange 模块的 MarketService 为例。

Steps

服务提供者（exchange）：搭建接口

在 exchange-api 下，新建 MarketDto 和 MarketServiceFeign。并在 exchange-service 下使用 MapStruct 进行映射。

在 dto 包，

@Data
@ApiModel(value = "Market RPC数据的传输对象")
public class MarketDto {// ……（一些属性）
}

在 feign 包，

@FeignClient(name = "exchange-service", configuration = OAuth2FeignConfig.class, path = "/markets")
public interface MarketServiceFeign {@GetMapping("/getMarket")MarketDto findByCoinId(Long sellCoinId, Long buyCoinId);
}

在 mappers 包，

// MapStruct 会自动生成实现类
@Mapper(componentModel = "spring")
public interface MarketDtoMappers {MarketDtoMappers INSTANCE = Mappers.getMapper(MarketDtoMappers.class);MarketDto entity2Dto(Market market);Market dto2Entity(MarketDto marketDto);List<MarketDto> entity2Dto(List<Market> market);List<Market> dto2Entity(List<MarketDto> marketDto);
}

在 exchange-service 的 MarketController 下实现 MarketServiceFeign，

@RestController
@RequestMapping("/markets")
@Api(tags = "交易市场的控制器")
public class MarketController implements MarketServiceFeign {// ……（其他controller）@Overridepublic MarketDto findByCoinId(Long sellCoinId, Long buyCoinId) {MarketDto marketDto = marketService.findByCoinId(buyCoinId, sellCoinId);return marketDto;}

服务消费者（finance）：调用接口

在 finance-service 的对应实现类注入 MarketServiceFeign 并调用方法，

@Service
public class AccountServiceImpl extends ServiceImpl<AccountMapper, Account> implements AccountService{@Autowiredprivate MarketServiceFeign marketServiceFeign;@Overridepublic UserTotalAccountVo getUserTotalAccount(Long userId) {// ……（业务逻辑）// 调用 Feign 远程接口MarketDto marketDto = marketServiceFeign.findByCoinId(basicCoinId, coinId);// ……}