Escaping a dot in a Map key in Yaml in Spring Boot

问题:

I have a following yml config:

foo:
  bar.com:
    a: b
  baz.com:
    a: c

With a following class Spring tries to inject map with keys 'bar' and 'baz', treating dots as separator:

public class JavaBean {
    private Map<String, AnotherBean> foo;
(...)
}

I have tried quoting the key (i.e. 'bar.com' or "bar.com") but to no avail - still the same problem. Is there a way around this?

回答1:

A slight revision of @fivetenwill's answer, which works for me on Spring Boot 1.4.3.RELEASE:

foo:
  "[bar.com]":
    a: b
  "[baz.com]":
    a: c

You need the brackets to be inside quotes, otherwise the YAML parser basically discards them before they get to Spring, and they don't make it into the property name.

回答2:

This is not possible if you want automatic mapping of yaml keys to Java bean attributes. Reason being, Spring first convert YAML into properties format. See section 24.6.1 of link below:

https://docs.spring.io/spring-boot/docs/current/reference/html/boot-features-external-config.html

So, your YAML is converted to:

foo.bar.com.a=b
foo.baz.com.a=c

Above keys are parsed as standard properties.

As a work around, you can use Spring's YamlMapFactoryBean to create a Yaml Map as it is. Then, you can use that map to create Java beans by your own.

@Configuration
public class Config {

    private Map<String, Object> foo;

    @Bean
    public Map<String, Object> setup() {
        foo = yamlFactory().getObject();
        System.out.println(foo); //Prints {foo={bar.com={a=b}, baz.com={a=c}}}
        return foo;
    }

    @Bean
    public YamlMapFactoryBean yamlFactory() {
        YamlMapFactoryBean factory = new YamlMapFactoryBean();
        factory.setResources(resource());
        return factory;
    }

    public Resource resource() {
        return new ClassPathResource("a.yaml"); //a.yaml contains your yaml config in question
    }

}

回答3:

This should work:

foo:
  ["bar.com"]:
    a: b
  ["baz.com"]:
    a: c

Inspired from Spring Boot Configuration Binding Wiki