1.場景還原

     在多模組開發的過程中，為了避免一些重複的“硬程式碼”的編寫，我們可以在A模組中定義一個實現類，然後在B模組中遠端呼叫，這樣減少了程式碼冗餘及業務硬程式碼的重複編寫

2.實現方案

這裡以筆者專案的訂單模組遠端呼叫狀態機模組介面為例，僅供參考

①訂單模組的pom依賴

<dependency>
   <groupId>io.github.openfeign</groupId>
   <artifactId>feign-core</artifactId>
   <version>9.5.0</version>
</dependency>
 
<dependency>
   <groupId>io.github.openfeign</groupId>
   <artifactId>feign-slf4j</artifactId>
   <version>9.5.0</version>
</dependency>
<dependency>
   <groupId>io.github.openfeign</groupId>
   <artifactId>feign-hystrix</artifactId>
 
   <version>9.5.0</version>
</dependency>
<dependency>
   <groupId>io.github.openfeign</groupId>
   <artifactId>feign-jackson</artifactId>
   <version>9.5.0</version>
</dependency>

②訂單模組中狀態機ip的配置conf.yml

fsm:
  url: http://localhost:8072/

③遠端url的控制元件申明

@ConfigurationProperties(prefix = "fsm")
@PropertySource(value = "classpath:conf.yml")
@Component
@Data
public class SelfConf {

    @Value("${url}")
    private String url;
}

④狀態機模組定義一個查詢訂單詳情的controller

@RestController
@Slf4j
@RequestMapping("/v1.0/dispatch/fsm")
public class DispatchFsmController {

    @Autowired
private YiViDispatchOrderMapper yiViDispatchOrderMapper;
@GetMapping(value = "/feign")
    public YiViDispatchOrder feign(){
        return yiViDispatchOrderMapper.selectByPrimaryKey("10efe91d-8379-11e8-b461-ecebb8d1d4af");
}}

⑤訂單模組實現遠端呼叫的client

首先定義service

public interface DispatchOrderFsmService {

    @Headers({"Content-Type: application/json"})
    @RequestLine("GET /v1.0/dispatch/fsm/feign")
    public YiViDispatchOrder feign();
}

然後實現client

@Service
public class DispatchOrderFsmClient {

    @Autowired
private SelfConf selfConf;
    private DispatchOrderFsmService init()
    {
        return Feign.builder()
                    .decoder(new JacksonDecoder())
                    .encoder(new JacksonEncoder())
                    .target(DispatchOrderFsmService.class, this.selfConf.getUrl());
}

    public YiViDispatchOrder feign()
    {
        DispatchOrderFsmService orderFsmService = init();
        return orderFsmService.feign();
}

}

⑥訂單模組client的controller

@RestController
@RequestMapping("/v1.0/dispatch/order")
public class DispatchOrderController {
@Autowired
private DispatchOrderFsmClient dispatchOrderFsmClient;
//測試
@RequestMapping(value = "/feign", method = RequestMethod.GET)
    @ResponseBody
public YiViDispatchOrder feign() throws Exception {

        return  dispatchOrderFsmClient.feign();
}}

3.測試用例

①狀態機模組訂單詳情介面的訪問

②訂單模組client的訪問

這樣通過訪問訂單模組的介面間接訪問到了狀態機模組介面；

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