Does Spring Support JSON Configuration?

Question

Does anyone know if Spring has any extensions that allow for configuring its ApplicationContext via JSON (or really any other format) rather than XML? I couldn't find anything in the official docs, but I was wondering if there were any other open source extensions that could allow this.

Just to be clear, I'm not talking about configuring SpringMVC to set up a RESTful JSON-based web service or anything like that, just if it's possible to do Spring app configuration via JSON instead of XML.

Answer 1

As far as I know there is no project to support JSON as configuration source. It should be relatively easy to kick-start, (Spring container has no dependency on XML, it is just a way to construct bean definitions). However it is much more work than you might think.

Note that Spring provides xml-schema to assist you in writing correct XML. You won't get that much in JSON. Also many DSLs were built on top of Spring XML and custom namespaces support (spring-integration, mule-esb and others use it).

If you hate XML (many do), try out Java Configuration, available since 3.0 and improved in 3.1:

@Configuration
public class MyBeans {

    @Bean
    public Foo foo() {
        return new Foo();
    }

    @Bean
    public Bar bar() {
        return new Bar(foo());
    }

    @Bean
    public Buzz buzz() {
        Buzz buzz = new Buzz();
        buzz.setFoo(foo());
        return buzz;
    }

}

Interesting fact: thanks to some fancy proxying, foo() is called exactly once here, even though referenced twice.

Answer 2

Try JSConf library available on maven central, it's support Properties, HOCON and JSON format.

You can inject values from external file to your service and more !

Sample usage of JavaConfig :

You data stored on file app.conf

{ 
"root":{
"simpleConf":{
    "url":"Hello World",
    "port":12,
    "aMap":{
        "key1":"value1",
        "key2":"value2"
    },
    "aList":[
        "value1",
        "value2"
    ]
}}

You service where your configuration must be inject

@Service("service")
public class Service {
    @Autowired
    private ConfigBean configBean;
}

Declare a interface to access your configuration values from your service

@ConfigurationProperties("root/simpleConf")
public interface ConfigBean {
    String getUrl();
    int getPort();
    Map getAMap();
    List getAList();
}

And your Spring configuration bean :

@Configuration
public class ContextConfiguration {
    @Bean
    public static ConfigurationFactory configurationFactory() {
        return new ConfigurationFactory().withResourceName("app.conf") //
                .withScanPackage("org.jsconf.core.sample.bean");
    }
}