spring-boot camel case nested property as environment variable

问题

I have a spring boot application and want to set, though environment variables, in a class annotated with @ConfigurationProperties a second level nested property which is camel case. Here is an example of the class:

@SpringBootApplication
@EnableConfigurationProperties(SpringApp.Props.class)
@RestController
public class SpringApp {

  private Props props;

  @ConfigurationProperties("app")
  public static class Props {
    private String prop;
    private Props nestedProps;

    public String getProp() {
      return prop;
    }

    public void setProp(String prop) {
      this.prop = prop;
    }

    public Props getNestedProps() {
      return nestedProps;
    }

    public void setNestedProps(Props nestedProps) {
      this.nestedProps = nestedProps;
    }

  }

  @Autowired
  public void setProps(Props props) {
    this.props = props;
  }

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

  @RequestMapping("/")
  Props getProps() {
    return props;
  }

}

when I try to run the application with following environment variables:

APP_PROP=val1
APP_NESTED_PROPS_PROP=val2
APP_NESTED_PROPS_NESTED_PROPS_PROP=val3

I'm getting following response from the service:

{
  "prop": "val1",
  "nestedProps": {
    "prop": "val2",
    "nestedProps": null
  }
}

Is this the expected behavior? I was expecting something like this:

{
  "prop": "val1",
  "nestedProps": {
    "prop": "val2",
    "nestedProps": {
      "prop": "val3",
      "nestedProps": null
    }
  }
}

When I am setting the properties through application parameters (eg: --app.prop=val1 --app.nestedProps.prop=val2 --app.nestedProps.nestedProps.prop=val3), I'm getting expected response.

Is there any workaround using environment variables and without modifying the code to get the expected behavior?

Note: I did some debugging and seems the problem is originated in org.springframework.boot.bind.RelaxedNames not generating candidates for this cases. Here is a test I did to demonstrate it (it fails):

@Test
public void shouldGenerateRelaxedNameForCamelCaseNestedPropertyFromEnvironmentVariableName() {
  assertThat(new RelaxedNames("NESTED_NESTED_PROPS_PROP"), hasItem("nested.nestedProps.prop"));
}

回答1:

I would try with the NESTED_NESTEDPROPS_PROP, bcs 'nestedProps' is one property

The _ delimiter must not be used within a property name. i.e. database-platform must be written as DATABASEPLATFORM and not DATABASE_PLATFORM.

source: https://github.com/spring-projects/spring-boot/wiki/Relaxed-Binding-2.0

来源：https://stackoverflow.com/questions/31729516/spring-boot-camel-case-nested-property-as-environment-variable

标签

java

spring-boot

environment-variables