本文目錄
4.1 方案一：擴大註解 @EnableFeignClients掃描的包的範圍
4.2 方案二：在註解@EnableFeignClients指定clients
一、背景描述
微服務項目，spring boot (v2.1.5.RELEASE) ，今天在ServiceA微服務裏添加一個功能，通過FeignClient調用ServiceB的接口。
在本項目裏通過@Autowired自動注入方式注入客戶端接口
@Autowired
private ScreenSaverClient screenSaverClient;
然後啓動項目，結果就報 APPLICATION FAILED TO START 項目啓動失敗。
二、報錯信息
報錯內容如下圖所示：
三、錯誤原因
報這個錯，是因爲啓動類裏的註解 @EnableFeignClients沒有掃描到這個包，在本項目裏是沒有掃描到com.iot.basic.iotsmarthome.api.client.screensaver.ScreenSaverClient這個。
以下是本項目的錯誤的啓動類代碼：
@SpringBootApplication(exclude = {DataSourceAutoConfiguration.class})
@EnableDiscoveryClient
@ComponentScan(basePackages = {"com.uiotsoft.back","com.uiotsoft.framework"})
@EnableFeignClients(basePackages = {"com.uiotsoft.back.operation.facade.feign"})
@ServletComponentScan(basePackages ={"com.uiotsoft.back.operation.config"} )
@EnableSwagger2
@EnableHystrix
@EnableConfigurationProperties
public class OperationApplication {
public static void main(String[] args) throws Exception {
SpringApplication.run(OperationApplication.class, args);
}
}
四、解決方案
方案有多種，這裏先寫兩種，以後再更新：
4.1 方案一：擴大註解 @EnableFeignClients掃描的包的範圍
@SpringBootApplication(exclude = {DataSourceAutoConfiguration.class})
@EnableDiscoveryClient
@ComponentScan(basePackages = {"com.uiotsoft.back","com.uiotsoft.framework"})
@EnableFeignClients(basePackages = {"com.uiotsoft"})
@ServletComponentScan(basePackages ={"com.uiotsoft.back.operation.config"} )
@EnableSwagger2
@EnableHystrix
@EnableConfigurationProperties
public class OperationApplication {
public static void main(String[] args) throws Exception {
SpringApplication.run(OperationApplication.class, args);
}
}
網上有說“將 FeignClient 這個 bean 放在和 Application 啓動類同級目錄”，其道理和作用是和方案一相同的。
4.2 方案二：在註解@EnableFeignClients指定clients
@SpringBootApplication(exclude = {DataSourceAutoConfiguration.class})
@EnableDiscoveryClient
@ComponentScan(basePackages = {"com.uiotsoft.back","com.uiotsoft.framework"})
@EnableFeignClients(basePackages = {"com.uiotsoft.back.operation.facade.feign"}, clients = ScreenSaverClient.class)
@ServletComponentScan(basePackages ={"com.uiotsoft.back.operation.config"} )
@EnableSwagger2
@EnableHystrix
@EnableConfigurationProperties
public class OperationApplication {
public static void main(String[] args) throws Exception {
SpringApplication.run(OperationApplication.class, args);
}
}
當然方案二有個弊端，就是項目裏存在多個clients（需要調用很多其他的服務時）的時候，就需要指定很多個，所以如果通過FeignClient調用多個服務的時候，用方案一比較合適。
完結！
以下不用看，只是方便被搜索到
***************************
APPLICATION FAILED TO START
***************************Description:
Parameter 0 of constructor in com.uiotsoft.back.operation.facade.service.impl.ScreenSaverClientServiceImpl required a bean of type 'com.uiotsoft.basic.iotsmarthome.api.client.screensaver.ScreenSaverClient' that could not be found.
The injection point has the following annotations:
- @org.springframework.beans.factory.annotation.Autowired(required=true)
Action:Consider defining a bean of type 'com.uiotsoft.basic.iotsmarthome.api.client.screensaver.ScreenSaverClient' in your configuration.