应用程序属性中占位符的春季启动用法 [英] spring boot usage of placeholder in application properties

问题描述

我已经编写了一个使用mysql(5.7版)的简单的Spring Boot应用程序(版本springboot 2.0).

I have written a simple spring boot application(version springboot 2.0) which uses mysql(version 5.7).

application.properties 代码段

spring.datasource.url = jdbc:mysql://localhost:3306/test?useSSL=false
spring.datasource.username = testuser
spring.datasource.password = testpassword
spring.datasource.driver-class-name=com.mysql.jdbc.Driver

当我在本地运行它时，它工作正常. 如果我想在docker中运行此春季启动应用程序，则可以更改

When I run it locally, it works fine. If I want to run this spring boot application in docker then I can change

spring.datasource.url = jdbc:mysql://mysql-container:3306/test?useSSL=false

mysql-container使用dockerhub上的mysql:5.7镜像运行.

但是，我想从某些占位符属性文件中更改主机的值.这样看起来像:

However I want to change value of host from some placeholder properties file. so that this looks something like:

spring.datasource.url = jdbc:mysql://${MYSQL_HOST}:3306/test?useSSL=false

注意:我不确定占位符格式.是$ {MYSQL_HOST}还是@ MYSQL_HOST @吗?

note: I am not sure about placeholder format. Is it ${MYSQL_HOST} or @MYSQL_HOST@ ?

您可以将此占位符文件命名为 placeholder.properties 或 placeholder.conf 或 .env 或其他任何名称.该文件的内容应类似于:

you can name this placeholder file as placeholder.properties or placeholder.conf or .env or anything. The content of that file should be something like:

MYSQL_HOST=localhost

或

MYSQL_HOST=some ip address

我可以创建.env或.env.test或.env.prod，并且可以根据要在其中运行应用程序的位置来引用该env文件.

I can create .env or .env.test or .env.prod and I can refer that env file based on where I want to run application.

更新-

我有两个问题:

1. 我应该在哪里保存placeholder.properties?是在/config/下还是在某些特定目录下?

1. Where should I keep placeholder.properties? Is it under /config/ or under some specific directory?

如何在application.properties中调用占位符?

how to invoke placeholder inside application.properties ?

有人可以建议吗?

推荐答案

感谢@Raheela Aslam和@ paulsm4的回答，还有更多研究发现了这个问题.

Thanks to answers by @Raheela Aslam and @paulsm4 and some more research found the issue.

我想要实现的目标:

1. 在docker中部署springboot应用程序，然后将其部署到kubernetes.
2. 我正在使用minikube进行本地测试，并希望将minikube ip传递到数据源url.

我如何修复它:

我分别为mysql_user，mysql_password和mysql_host创建了configmap.

I created configmap for mysql_user, mysql_password, mysql_host with respective values.

kubectl create configmap mysql-config \
--from-literal=mysql_user=testuser \
--from-literal=mysql_password=testuserpass \
--from-literal=mysql_user=$(minikube ip) 

并在application.properties中使用了以下内容

and used these inside application.properties something like below

spring.datasource.url = jdbc:mysql://${MYSQL_HOST}:3306/test?useSSL=false
spring.datasource.username = ${MYSQL_USER}
spring.datasource.password = ${MYSQL_PASSWORD}
spring.datasource.driver-class-name=com.mysql.jdbc.Driver

，然后在Deployment.yaml中将configmap值用于kubernetes. 然后开始部署服务.

and then used configmap values in deployment.yaml for kubernetes. Then did start service for deployment.

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