Springboot 整合 SpringCloud组件-Config 配置中心 ConfigClient (七)

青旅半醒 2021-12-15 05:15 373阅读 0赞

在上一篇[https://blog.csdn.net/qq\_35387940/article/details/94616604][https_blog.csdn.net_qq_35387940_article_details_94616604] 我们已经将配置中心 ConfigServer成功完成整合，也和github打通，那么这篇我们将实现ConfigClient ，通过 ConfigServer去读取github里的相关值。

大致流程如下图：

![Azure (2).png][Azure _2_.png]

不多说，我们开始整合，创建一个springboot项目，起名config-client:

![watermark_type_ZmFuZ3poZW5naGVpdGk_shadow_10_text_aHR0cHM6Ly9ibG9nLmNzZG4ubmV0L3FxXzM1Mzg3OTQw_size_16_color_FFFFFF_t_70][]

pom.xml:

<?xml version="1.0" encoding="UTF-8"?>
    <project xmlns="http://maven.apache.org/POM/4.0.0" xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
    	xsi:schemaLocation="http://maven.apache.org/POM/4.0.0 http://maven.apache.org/xsd/maven-4.0.0.xsd">
    	<modelVersion>4.0.0</modelVersion>
    	<parent>
    		<groupId>org.springframework.boot</groupId>
    		<artifactId>spring-boot-starter-parent</artifactId>
    		<version>2.1.6.RELEASE</version>
    		<relativePath/> 
    	</parent>
    	<groupId>com.cloud</groupId>
    	<artifactId>config-client</artifactId>
    	<version>0.0.1-SNAPSHOT</version>
    	<name>config-client</name>
    	<description>Demo project for Spring Boot</description>
    
    	<properties>
    		<java.version>1.8</java.version>
    		<spring-cloud.version>Finchley.RELEASE</spring-cloud.version>
    	</properties>
    
    	<dependencies>
    		<dependency>
    			<groupId>org.springframework.cloud</groupId>
    			<artifactId>spring-cloud-starter-config</artifactId>
    		</dependency>
    		<dependency>
    			<groupId>org.springframework.boot</groupId>
    			<artifactId>spring-boot-starter-web</artifactId>
    		</dependency>
    		<dependency>
    			<groupId>org.springframework.cloud</groupId>
    			<artifactId>spring-cloud-starter-netflix-eureka-client</artifactId>
    		</dependency>
    		<dependency>
    			<groupId>org.springframework.boot</groupId>
    			<artifactId>spring-boot-starter-test</artifactId>
    			<scope>test</scope>
    		</dependency>
    	</dependencies>
    
    	<dependencyManagement>
    		<dependencies>
    			<dependency>
    				<groupId>org.springframework.cloud</groupId>
    				<artifactId>spring-cloud-dependencies</artifactId>
    				<version>${spring-cloud.version}</version>
    				<type>pom</type>
    				<scope>import</scope>
    			</dependency>
    		</dependencies>
    	</dependencyManagement>
    
    	<build>
    		<plugins>
    			<plugin>
    				<groupId>org.springframework.boot</groupId>
    				<artifactId>spring-boot-maven-plugin</artifactId>
    			</plugin>
    		</plugins>
    	</build>
    
    </project>

接着我们写一个controller， 写一个接口来测试读取GitHub的配置文件值，ConfigClientController.java：

import org.springframework.beans.factory.annotation.Value;
    import org.springframework.web.bind.annotation.RequestMapping;
    import org.springframework.web.bind.annotation.RestController;
    
    @RestController
    public class ConfigClientController {
    
    
        @Value("${testValue}")
        String testValue;
        @RequestMapping(value = "/getTestValue")
        public String getTestValue(){
    
            return "获取到的配置文件值为："+testValue;
        }
    
    }

然后是配置文件，这里我们需要创建一个bootstrap.yml (或者bootstrap.properties)：

eureka:
      instance:
    #以IP地址注册到服务中心，相互注册使用IP地址
        preferIpAddress: true
        instance-id: ${spring.cloud.client.ip-address}:${server.port}
      client:
        serviceUrl:
          defaultZone: http://localhost:8761/eureka/
    spring:
      application:
    #和git里的文件名（application）对应
        name: config-client
      cloud:
        config:
    #分支
          label: master
    #环境值
          profile: dev
    #config-server的地址
          uri: http://localhost:8888/
    server:
      port: 8881

在启动类加上注解，也将这个服务注册到Eureka注册中心去：

import org.springframework.boot.SpringApplication;
    import org.springframework.boot.autoconfigure.SpringBootApplication;
    import org.springframework.cloud.netflix.eureka.EnableEurekaClient;
    
    @EnableEurekaClient
    @SpringBootApplication
    public class ConfigClientApplication {
    
    	public static void main(String[] args) {
    		SpringApplication.run(ConfigClientApplication.class, args);
    	}
    
    }

OK，到这里已经准备完毕，将config-client服务也跑起来，

访问[http://localhost:8881/getTestValue][http_localhost_8881_getTestValue]  ：

![watermark_type_ZmFuZ3poZW5naGVpdGk_shadow_10_text_aHR0cHM6Ly9ibG9nLmNzZG4ubmV0L3FxXzM1Mzg3OTQw_size_16_color_FFFFFF_t_70 1][]

OK，git上面的配置值成功获取。

PS： 补充2个错误，项目无法正常运行

一、如果你在运行项目出现以下这类错误：

org.springframework.beans.factory.BeanCreationException: Error creating bean with name 'configClientController': Injection of autowired dependencies failed; nested exception is java.lang.IllegalArgumentException: Could not resolve placeholder 'testValue' in value "${testValue}"

不用想，你的config-client 已经在项目跑起来尝试地去访问config-server，然后尝试读取git里面的值，发现找不到才报的错。

那么怎么解决， 1.请对比配置文件里面有没有这个配置项的key 2.请对照好git里面配置文件的名字 是不是跟我们这个项目里的服务名一致. 3.config-server服务有没有正常运行，端口是不是对应起来了 4.这个服务用的配置文件是bootstrap.yml，优先级大于application.yml，有没有配置信息搞乱了。

二、如果你在运行项目出现以下这类错误：

2019-07-04 15:36:46.738  INFO 16380 --- [      Thread-15] com.netflix.discovery.DiscoveryClient    : Shutting down DiscoveryClient ...
    2019-07-04 15:36:46.752  INFO 16380 --- [nfoReplicator-0] com.netflix.discovery.DiscoveryClient    : DiscoveryClient_CLIENT-TEST/192.168.2.246:8881 - registration status: 204
    2019-07-04 15:36:46.753  INFO 16380 --- [nfoReplicator-0] com.netflix.discovery.DiscoveryClient    : DiscoveryClient_CLIENT-TEST/192.168.2.246:8881: registering service...
    2019-07-04 15:36:46.756  INFO 16380 --- [nfoReplicator-0] com.netflix.discovery.DiscoveryClient    : DiscoveryClient_CLIENT-TEST/192.168.2.246:8881 - registration status: 204
    2019-07-04 15:36:46.756  INFO 16380 --- [      Thread-15] com.netflix.discovery.DiscoveryClient    : Unregistering ...
    2019-07-04 15:36:46.761  INFO 16380 --- [      Thread-15] com.netflix.discovery.DiscoveryClient    : DiscoveryClient_CLIENT-TEST/192.168.2.246:8881 - deregister  status: 200
    2019-07-04 15:36:46.769  INFO 16380 --- [      Thread-15] com.netflix.discovery.DiscoveryClient    : Completed shut down of DiscoveryClient

不用想，这多半是pom.xml里面忘记导入spring-boot-starter-web依赖了，添加依赖即可。

[https_blog.csdn.net_qq_35387940_article_details_94616604]: https://blog.csdn.net/qq_35387940/article/details/94616604
[Azure _2_.png]: /images/20211214/90bd1169c7c84e7993071a6925488350.png
[watermark_type_ZmFuZ3poZW5naGVpdGk_shadow_10_text_aHR0cHM6Ly9ibG9nLmNzZG4ubmV0L3FxXzM1Mzg3OTQw_size_16_color_FFFFFF_t_70]: /images/20211214/c27b8027f7334d01b29aef2663aa43c2.png
[http_localhost_8881_getTestValue]: http://localhost:8881/getTestValue
[watermark_type_ZmFuZ3poZW5naGVpdGk_shadow_10_text_aHR0cHM6Ly9ibG9nLmNzZG4ubmV0L3FxXzM1Mzg3OTQw_size_16_color_FFFFFF_t_70 1]: /images/20211214/3fec09d9acc04c63911a4449a2d162bf.png