使用环境变量的Spring Boot配置

Question

我有一个Spring Boot应用程序，它与DB交互，使用spring data REST提供资源。我想从环境变量中获得配置。下面是我的属性文件。

spring.datasource.url=${mysql.url}
spring.datasource.username=${mysql.user}
spring.datasource.password=${mysql.password}

我的环境变量在图像https://ibb.co/cyxsnc中

我甚至还尝试了下面的配置

spring.datasource.url=${MySQL_Url}
spring.datasource.username=${MySQL_User}
spring.datasource.password=${MySQL_Password}

org.springframework.beans.factory.UnsatisfiedDependencyException: Error creating bean with name 'org.springframework.boot.autoconfigure.orm.jpa.HibernateJpaAutoConfiguration': Unsatisfied dependency expressed through constructor parameter 0; nested exception is org.springframework.beans.factory.BeanCreationException: Error creating bean with name 'dataSource' defined in class path resource [org/springframework/boot/autoconfigure/jdbc/DataSourceConfiguration$Tomcat.class]: Bean instantiation via factory method failed; nested exception is org.springframework.beans.BeanInstantiationException: Failed to instantiate [org.apache.tomcat.jdbc.pool.DataSource]: Factory method 'dataSource' threw exception; nested exception is java.lang.IllegalArgumentException: URL must start with 'jdbc'

Project
|-- src/main/java
    |-- com.example.app
        |-- DemoApplication.java
|-- src/main/resources
    |-- application.properties

注意：如果设置如下所示的值，配置工作正常

spring.datasource.url=jdbc:mysql://localhost:3306/ex_man
spring.datasource.username=root
spring.datasource.password=root

我错过了什么？

Answer 1

请查看以下文档：https://docs.spring.io/spring-boot/docs/current/reference/html/boot-features-external-config.html

尝试命名您的环境变量：

spring_datasource_url

spring_datasource_username

spring_datasource_password

更新：

package com.example.environment_vars;

import org.springframework.beans.factory.annotation.Value;
import org.springframework.boot.CommandLineRunner;
import org.springframework.boot.SpringApplication;
import org.springframework.boot.autoconfigure.SpringBootApplication;
import org.springframework.context.annotation.Bean;

@SpringBootApplication
public class EnvironmentVarsApplication {

    @Value("${env.var}")
    private String envVar;

    @Bean
    public CommandLineRunner commandLineRunner() {
        return new CommandLineRunner() {
            @Override
            public void run(String[] arg0) throws Exception {
                System.out.println(envVar);
            }
        };
    }

    public static void main(String[] args) {
        SpringApplication.run(EnvironmentVarsApplication.class, args);
    }
}