Plain Simple MongoDB Spring Integration

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=localhost
db.port=27017
app.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