- Given a java application, We would like to read the property file defined in HOCON (Human-Optimized Config Object Notation.) or JSON format.
- The property files use the suffix .conf e.g. application.conf, reference.conf.
- We are performing following operations:
- Reading the JSON property file defined in reference.conf file.
- Substituting environment variable in reference conf file.
- java_directory = ${?JAVA_HOME}
- We have created runnable jar to invoke main method of jar.
- We are logging the properties using slf4j-log4j12.
TypeSafe Config Maven dependency:
<dependency> <groupId>com.typesafe</groupId> <artifactId>config</artifactId> <version>1.3.0</version> </dependency>
Property file in HOCON/JSON format (reference.conf file)
userInfo { name=Mike age = 30 roles = [ guest read-only ] } database { user=admin password=admin } //Read environment variable java_directory = ${?JAVA_HOME}
Program to read HOCON or JSON property file in java
We are loading reference.conf using ConfigFactory.load()
package org.learn.application; import org.slf4j.Logger; import org.slf4j.LoggerFactory; import com.typesafe.config.Config; import com.typesafe.config.ConfigFactory; public class Application { private static final Logger logger = LoggerFactory.getLogger(Application.class); private static final Config config = ConfigFactory.load(); public static void main(String[] args) { logger.info("Start Reading HOCON file:"); logger.info("UserName={}",config.getString("userInfo.name")); logger.info("age={}",config.getInt("userInfo.age")); logger.info("Array of roles={}",config.getStringList("userInfo.roles")); logger.info("Database userName={}",config.getString("database.user")); logger.info("Database password={}",config.getString("database.password")); //Read environment variable if(config.hasPath("java_directory")) { logger.info("Java installed directory={}",config.getString("java_directory")); } logger.info("End reading HOCON file"); } }
Output – Read HOCON or JSON config file in java
2016-07-06 21:09:58,754 [INFO] org.learn.application.Application [main] Start Reading HOCON file: 2016-07-06 21:09:58,759 [INFO] org.learn.application.Application [main] UserName=Mike 2016-07-06 21:09:58,760 [INFO] org.learn.application.Application [main] age=30 2016-07-06 21:09:58,761 [INFO] org.learn.application.Application [main] Array of roles=[guest, read-only] 2016-07-06 21:09:58,761 [INFO] org.learn.application.Application [main] Database userName=admin 2016-07-06 21:09:58,761 [INFO] org.learn.application.Application [main] Database password=admin 2016-07-06 21:09:58,761 [INFO] org.learn.application.Application [main] Java installed directory=C:\Program Files\Java\jdk1.8.0_60 2016-07-06 21:09:58,761 [INFO] org.learn.application.Application [main] End reading HOCON file
Download Code – TypeSafe/Config HOCON Java Application