You know what is MongoDB and what is Spring Framework and want to use the first inside the second? Here's short plain and simple integration between the two:

• Properties file with server and database details (resides in classpath in this example):

db.host=localhostdb.port=27017app.db.name=app

• If you don't use Java-based container configuration (you should start using it!):

1. application-config.xml (or whatever you call it):
   

   <beans xmlns="http://www.springframework.org/schema/beans"       xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"       xmlns:context="http://www.springframework.org/schema/context"       xsi:schemaLocation="http://www.springframework.org/schema/beans           http://www.springframework.org/schema/beans/spring-beans-3.0.xsd           http://www.springframework.org/schema/context           http://www.springframework.org/schema/context/spring-context-3.0.xsd">    <context:property-placeholder                 location="classpath:db.properties"/>    <bean id="mongo" class="com.mongodb.Mongo">       <constructor-arg value="${db.host}"/>       <constructor-arg value="${db.port}"/>   </bean>   <bean id="db"       class="com.mongodb.spring.config.DbFactoryBean">       <property name="mongo" ref="mongo"/>       <property name="name" value="${app.db.name}"/>   </bean></beans>

2. The com.mongodb.spring.config.DbFactoryBean class:
   

    public class DbFactoryBean implements FactoryBean<DB> {            private Mongo mongo;        private String name;            @Override        public DB getObject() throws Exception {            Assert.notNull(mongo);            Assert.notNull(name);            return mongo.getDB(name);        }          @Override       public Class<?> getObjectType() {           return DB.class;       }          @Override       public boolean isSingleton() {           return true;       }          @Required       public void setMongo(Mongo mongo) {           this.mongo = mongo;       }       @Required          public void setName(String name) {           this.name = name;       } }

• If you do use Java-based container configuration - here's your @Configuration class:

    @Configuration    public class ApplicationConfiguration {            @Value("${app.db.name}")        private String appDbName;            @Value("${db.host}")        private String dbHost;           @Value("${db.port}")       private int dbPort;             @Bean       public DB db() throws UnknownHostException {           return mongo().getDB(appDbName);       }          @Bean       public Mongo mongo() throws UnknownHostException {           return new Mongo(dbHost, dbPort);       }   }

That's, actually, it - enjoy. If you feel some part of the puzzle is missing, please leave a comment.

This post was originally posted in my blog - http://jbaruch.wordpress.com