配置中心入门案例以及出现Could not resolve placeholder 'XXX' in value "${XXX}"的解决方式

编写配置中心的服务端

建立项目

修改 pom 文件添加 config-server 坐标

<?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 https://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>2.1.11.RELEASE</version>
        <relativePath/> <!-- lookup parent from repository -->
    </parent>
    <groupId>com.bjsxt</groupId>
    <artifactId>config-server</artifactId>
    <version>0.0.1-SNAPSHOT</version>
    <name>config-server</name>
    <description>config-server</description>

    <properties>
        <java.version>1.8</java.version>
        <spring-cloud.version>Greenwich.SR4</spring-cloud.version>
    </properties>

    <dependencies>
        <dependency>
            <groupId>org.springframework.boot</groupId>
            <artifactId>spring-boot-starter-web</artifactId>
        </dependency>
        <dependency>
            <groupId>org.springframework.cloud</groupId>
            <artifactId>spring-cloud-config-server</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>

修改配置文件添加 Git 地址（将配置文件上传到gitee上）

spring.application.name=yxf-config-server server.port=9010 eureka.client.service-url.defaultZone=http://admin:1234@192.168.41.242:5050/eureka/,http://admin:1234@192.168.41.242:5051/eureka/
 #Git配置 spring.cloud.config.server.git.uri=https://gitee.com/sakurayxf/config
#spring.cloud.config.server.git.username= #spring.cloud.config.server.git.password=

修改启动类

package com.bjsxt; import org.springframework.boot.SpringApplication; import org.springframework.boot.autoconfigure.SpringBootApplication; import org.springframework.cloud.config.server.EnableConfigServer; import org.springframework.cloud.netflix.eureka.EnableEurekaClient; @SpringBootApplication @EnableEurekaClient @EnableConfigServer public class ConfigServerApplication { public static void main(String[] args) { SpringApplication.run(ConfigServerApplication.class, args); } }

建立四个临时配置文件

注意命令规则html

经过配置中心访问配置文件

编写配置中心的客户端

修改 pom 文件添加配置中心客户端坐标

<?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 https://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>2.1.11.RELEASE</version>
        <relativePath/> <!-- lookup parent from repository -->
    </parent>
    <groupId>com.bjsxt</groupId>
    <artifactId>config-client</artifactId>
    <version>0.0.1-SNAPSHOT</version>
    <name>config-client</name>
    <description>config-client</description>

    <properties>
        <java.version>1.8</java.version>
        <spring-cloud.version>Greenwich.SR4</spring-cloud.version>
    </properties>

    <dependencies>
        <dependency>
            <groupId>org.springframework.boot</groupId>
            <artifactId>spring-boot-starter-web</artifactId>
        </dependency>
        <dependency>
            <groupId>org.springframework.cloud</groupId>
            <artifactId>spring-cloud-starter-config</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>

修改启动类

package com.bjsxt; import org.springframework.boot.SpringApplication; import org.springframework.boot.autoconfigure.SpringBootApplication; import org.springframework.cloud.netflix.eureka.EnableEurekaClient; import org.springframework.context.annotation.Bean; import org.springframework.context.support.PropertySourcesPlaceholderConfigurer; @SpringBootApplication @EnableEurekaClient public class ConfigClientApplication { public static void main(String[] args) { SpringApplication.run(ConfigClientApplication.class, args); } }

修改配置文件

修改配置文件的名称。客户端配置文件名称必须为 bootstrap.properties

spring.application.name=config-client server.port=9011 eureka.client.service-url.defaultZone=http://admin:1234@192.168.41.242:5050/eureka/,http://admin:1234@192.168.41.242:5051/eureka/
 #默认 false,这里设置 true,表示开启读取配置中心的配置 spring.cloud.config.discovery.enabled=true #对应 eureka 中的配置中心 serviceId，默认是 configserver spring.cloud.config.discovery.service-id=yxf-config-server #指定环境 spring.cloud.config.profile=dev #git 标签 spring.cloud.config.label=master

编写测试代码

package com.bjsxt.controller; import org.springframework.beans.factory.annotation.Value; import org.springframework.web.bind.annotation.RequestMapping; import org.springframework.web.bind.annotation.RestController; @RestController public class ShowController { @Value("${e-book}") private String msg; @RequestMapping("/msg") public String Msg(){ return msg; } }

在写这个的过程当中，实验了好几回都会出现这样的问题java

度娘也说了几种解决方法：git

1.就是配置文件必须是bootstrap.properties/ymlweb

2.就是spring

去找注册中心中的服务必须名称正确。apache

3.就是我遇到的这种，bootstrap

客户端的名称必须是config-client，不会就读取不到值。app

总之这个问题花费了我很长时间，最后仍是老师过来帮我解决的，问题也是不容易发现。maven

原文出处：https://www.cnblogs.com/sakura-yxf/p/12037074.htmlspring-boot