wildfly: reading properties from configuration dir

问题:

I'm trying to read deployment specific information from a properties file in my wildfly configuration folder. I tried this:

@Singleton
@Startup
public class DeploymentConfiguration {

  protected Properties props;

  @PostConstruct
  public void readConfig() {

    props = new Properties();
    try {
      props.load(getClass().getClassLoader().getResourceAsStream("my.properties"));
    } catch (IOException e) {
      // ... whatever
    }
  }

But apparently this is not working since the configuration folder is not in the classpath anymore. Now I can't find an easy way to do it. My favorite would be something like this:

@InjectProperties("my.properties")
protected Properties props;

The only solution I found on the web so far involves making my own OSGi module, but I believe there must be an easier way to do it (one without OSGi!). Can anyone show me how?

回答1:

If you want to explicitly read a file from the configuration directory (e.g. $WILDFLY_HOME/standalone/configuration or domain/configuration) there's a system property with the path in it. Simply do System.getProperty("jboss.server.config.dir"); and append your file name to that to get the file.

You wouldn't read it as a resource though, so...

String fileName = System.getProperty("jboss.server.config.dir") + "/my.properties";
try(FileInputStream fis = new FileInputStream(fileName)) {
  properties.load(fis);
}

Then the file would be loaded for you.

Also, since WildFly doesn't ship with OSGi support anymore, I don't know how creating an OSGi module would help you here.

回答2:

Here is a full example using just CDI, taken from this site.

1. Create and populate a properties file inside the WildFly configuration folder

   $ echo 'docs.dir=/var/documents' >> .standalone/configuration/application.properties
   

2. Add a system property to the WildFly configuration file.

   $ ./bin/jboss-cli.sh --connect
   [standalone@localhost:9990 /] /system-property=application.properties:add(value=${jboss.server.config.dir}/application.properties)
   

This will add the following to your server configuration file (standalone.xml or domain.xml):

<system-properties>
    <property name="application.properties" value="${jboss.server.config.dir}/application.properties"/>
</system-properties>

3. Create the singleton session bean that loads and stores the application wide properties

   import java.io.File;
   import java.io.FileInputStream;
   import java.io.IOException;
   import java.util.HashMap;
   import java.util.Map;
   import java.util.Properties;
   
   import javax.annotation.PostConstruct;
   import javax.ejb.Singleton;
   
   @Singleton
   public class PropertyFileResolver {
   
       private Logger logger = Logger.getLogger(PropertyFileResolver.class);
       private String properties = new HashMap<>();
   
       @PostConstruct
       private void init() throws IOException {
   
           //matches the property name as defined in the system-properties element in WildFly
           String propertyFile = System.getProperty("application.properties");
           File file = new File(propertyFile);
           Properties properties = new Properties();
   
           try {
               properties.load(new FileInputStream(file));
           } catch (IOException e) {
               logger.error("Unable to load properties file", e);
           }
   
           HashMap hashMap = new HashMap<>(properties);
           this.properties.putAll(hashMap);
       }
   
       public String getProperty(String key) {
           return properties.get(key);
       }
   }
   

4. Create the CDI Qualifier. We will use this annotation on the Java variables we wish to inject into.

   import java.lang.annotation.ElementType;
   import java.lang.annotation.Retention;
   import java.lang.annotation.RetentionPolicy;
   import java.lang.annotation.Target;
   
   import javax.inject.Qualifier;
   
   @Qualifier
   @Retention(RetentionPolicy.RUNTIME)
   @Target({ ElementType.METHOD, ElementType.FIELD, ElementType.CONSTRUCTOR })
   public @interface ApplicationProperty {
   
       // no default meaning a value is mandatory
       @Nonbinding
       String name();
   }
   

5. Create the producer method; this generates the object to be injected

   import javax.enterprise.inject.Produces;
   import javax.enterprise.inject.spi.InjectionPoint;
   import javax.inject.Inject;
   
   public class ApplicaitonPropertyProducer {
   
       @Inject
       private PropertyFileResolver fileResolver;
   
       @Produces
       @ApplicationProperty(name = "")
       public String getPropertyAsString(InjectionPoint injectionPoint) {
   
           String propertyName = injectionPoint.getAnnotated().getAnnotation(ApplicationProperty.class).name();
           String value = fileResolver.getProperty(propertyName);
   
           if (value == null || propertyName.trim().length() == 0) {
               throw new IllegalArgumentException("No property found with name " + value);
           }
           return value;
       }
   
       @Produces
       @ApplicationProperty(name="")
       public Integer getPropertyAsInteger(InjectionPoint injectionPoint) {
   
           String value = getPropertyAsString(injectionPoint);
           return value == null ? null : Integer.valueOf(value);
       }
   }
   

6. Lastly inject the property into one of your CDI beans

   import javax.ejb.Stateless;
   import javax.inject.Inject;
   
   @Stateless
   public class MySimpleEJB {
   
       @Inject
       @ApplicationProperty(name = "docs.dir")
       private String myProperty;
   
       public String getProperty() {
           return myProperty;
       }
   }
   

回答3:

The simplest thing you can do is to run standalone.sh with a -P option referencing your properties file (you need a URL file:/path/to/my.properties, or put the file in $WILDFLY_HOME/bin).

Then all properties from the file will be loaded as system properties.

For injecting configuration properties into your application classes, have a look at DeltaSpike Configuration, which supports different property sources like system properties, environment variables, JNDI entries and hides the specific source from your application.

Alternatively, to avoid setting system properties (which will be global in the sense of being visible to all applications deployed to your WildFly instance), you can also define a custom property source for DeltaSpike reading a properties file from any given location, and these properties will be local to your application.

回答4:

It sounds like the problem you are trying to solve is managing different (but probably similar) configuration files for running your application in different environments (ie, Production, QA, or even different customers). If that is the case, take a look at Jfig http://jfig.sourceforge.net/ . It would obviate the need for storing property files outside your classpath (but you still could).

What is needed is a hierarchical approach to configuration files. The ninety percent of configuration values that do not change can be maintained in a base file. The other ten percent (or less) may be maintained in their own distinct configuration file. At run time, the files are layered on top of each other to provide a flexible, manageable configuration. For example, in a development environment myhost.config.xml combines with dev.config.xml and base.config.xml to form my unique configuration.

Each configuration file may then be maintained in version control as they have unique names. Only the base files need to be modified when base values change, and it is easy to see the difference between versions. Another major benefit is that changes to the base configuration file will be exhaustively tested before deployment.

回答5:

InputStream in = null;
File confDir = new File(System.getProperty("jboss.server.config.dir"));
File fileProp = new File(confDir, "my.properties");

try{
    //teste fileProp.exists etc.

    in = new FileInputStream(fileProp);
    Properties properties = new Properties();
    properties.load(in);

    //You should throws or handle FileNotFoundException and IOException
}finally{
    try{
        in.close();
    }catch(Exception ignored){
    }
}

回答6:

To avoid this kind of problem the issue is to set the jboss.server.config.dir in VM arguments like that :

-Djboss.server.config.dir="[jboss_repository]/server/[default-all-standard-standalone]/conf" –server

回答7:

If you have in standalone.xml property:

<property name="my.properties" value="propertyValue"/>

you can wasily read it with:

static final String MY_PROPERTY = System.getProperty("my.properties");

Or if you specify context param in web.xml like:

<context-param>
    <param-name>MyProperty</param-name>
    <param-value>MyPropertyValue</param-value>
</context-param>

You can read it in Java bean:

String myProperty= getServletContext().getInitParameter("MyProperty");