Why cannot I obtain the placeholder from the configuration file

[robben009]

  <dependency>
      <groupId>org.apache.shardingsphere</groupId>
      <artifactId>shardingsphere-jdbc</artifactId>
     <version>5.5.0</version>
</dependency>

l hava a application.yml config file. file have a config content is

dbPwd: 1234556

spring:
  datasource:
    driver-class-name: org.apache.shardingsphere.driver.ShardingSphereDriver
    url: jdbc:shardingsphere:classpath:sharding-dev.yml?placeholder-type=system_props

and l hava a sharding-dev.yml file，config content is

dataSources:
  ds_0:
    dataSourceClassName: com.zaxxer.hikari.HikariDataSource
    driverClassName: com.mysql.cj.jdbc.Driver
    jdbcUrl: ***
    username: ***
    password: $${dbPwd::}

why $${dbPwd::} is not effect？

[linghengqian]

Obviously, it's because you haven't set the system property of dbPwd. The content in application.yml will not be automatically set as system properties.

[robben009]

Obviously, it's because you haven't set the system property of dbPwd. The content in application.yml will not be automatically set as system properties.

Is there support for getting properties from application.properties instead of placeholders

[linghengqian]

• In this case, you need to actively implement the spi of the shardingsphere jdbc driver to read the application.yml on the classpath.

• You cannot put the spi implementation class of shardingsphere into the life cycle of spring context, because shardingsphere jdbc datasource allows multiple instances, and the spi implementation class is easily created and used by internal classes. For spring boot, you can directly regard spring context as a single instance such as jaas.

• I would say you can feel free to consult the spring boot documentation to understand why the spring context's internal map itself is not suitable for storing metadata.

[linghengqian]

By the way, you can create a spring bean of applicationrunner to initialize a bunch of system properties.

[robben009]

ok l get, thanks