【Java异常】Spring boot启动失败@org.springframework.beans.factory.annotation.Autowired(required=true)

太过爱你忘了你带给我的痛 2023-02-18 11:56 12阅读 0赞

**本文目录**

一、背景描述

二、报错信息

三、错误原因

四、解决方案

4.1 方案一：扩大注解 @EnableFeignClients扫描的包的范围

4.2 方案二：在注解@EnableFeignClients指定clients

--------------------

# 一、背景描述 #

微服务项目，spring boot (v2.1.5.RELEASE) ，今天在ServiceA微服务里添加一个功能，通过FeignClient调用ServiceB的接口。

在本项目里通过@Autowired自动注入方式注入客户端接口

@Autowired
    private ScreenSaverClient screenSaverClient;

然后启动项目，结果就报 **APPLICATION FAILED TO START** 项目启动失败。

# 二、报错信息 #

报错内容如下图所示：

![watermark_type_ZmFuZ3poZW5naGVpdGk_shadow_10_text_aHR0cHM6Ly9ibG9nLmNzZG4ubmV0L3dlaXhpbl80NDI5OTAyNw_size_16_color_FFFFFF_t_70][]

# 三、错误原因 #

报这个错，是因为启动类里的**注解 @EnableFeignClients**没有扫描到这个包，在本项目里是没有扫描到com.iot.basic.iotsmarthome.api.client.screensaver.ScreenSaverClient这个。

以下是本项目的错误的启动类代码：

@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、解决方案 #

方案有多种，这里先写两种，以后再更新：

## 4.1 方案一：**扩大注解 @EnableFeignClients扫描的包的范围** ##

@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);
    	}
    	
    }

网上有说“将 **FeignClient** 这个 bean 放在和 Application 启动类同级目录”，其道理和作用是和方案一相同的。

## 4.2 方案二：在注解@EnableFeignClients指定clients ##

![watermark_type_ZmFuZ3poZW5naGVpdGk_shadow_10_text_aHR0cHM6Ly9ibG9nLmNzZG4ubmV0L3dlaXhpbl80NDI5OTAyNw_size_16_color_FFFFFF_t_70 1][]

@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);
    	}
    	
    }

当然方案二有个弊端，就是项目里存在多个clients（需要调用很多其他的服务时）的时候，就需要指定很多个，所以如果通过**FeignClient**调用多个服务的时候，用方案一比较合适。

完结！

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.

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[watermark_type_ZmFuZ3poZW5naGVpdGk_shadow_10_text_aHR0cHM6Ly9ibG9nLmNzZG4ubmV0L3dlaXhpbl80NDI5OTAyNw_size_16_color_FFFFFF_t_70 1]: https://img-blog.csdnimg.cn/2020061718053483.png?x-oss-process=image/watermark,type_ZmFuZ3poZW5naGVpdGk,shadow_10,text_aHR0cHM6Ly9ibG9nLmNzZG4ubmV0L3dlaXhpbl80NDI5OTAyNw==,size_16,color_FFFFFF,t_70