Its very easy to integrate the MongoDB with a java driver …
Download Java Driver
Once downloaded the connection to the mongodb is made using configServer() and other methods are self explanatory.
public class MongoDB {
private String hostname ="localhost";
private int port = 27017;
private String dbStore = "myFirstApplication";
private DB database;
private DBCollection collection;
public MongoDB(){
configServer();
}
/**
* doing the configuration. By default the collection is set to testing.
*/
private void configServer() {
try {
Mongo mongo = new Mongo(hostname,port);
database = mongo.getDB(dbStore);
collection = database.getCollection("testing");
} catch (UnknownHostException e) {
e.printStackTrace();
} catch (MongoException e) {
e.printStackTrace();
}
}
/**
* Insert the json object to DB
* @param jsonString
*/
public void insert(String jsonString){
DBObject dbobject = (DBObject) JSON.parse(jsonString);
collection.insert(dbobject);
}
/**
* find the json object using the key.. Not very efficient though
* @param key
* @param value
* @return
*/
public DBObject find(String key,String value){
BasicDBObject query = new BasicDBObject(key,value);
DBObject dbObject = collection.findOne(query);
return dbObject;
}
/**
* find an object with the unique object id.
* This throws IllegalArgumentException if the object id doesnt exist
* @param objectId
* @return
*/
public DBObject find(ObjectId objectId) {
BasicDBObject query = new BasicDBObject("_id",objectId);
return collection.findOne(query);
}
/**
* delete the json on the basis of key
* @param key
* @param value
*/
public void delete (String key,String value){
BasicDBObject query = new BasicDBObject(key,value);
collection.remove(query);
}
/**
* delete by the uniqied id given by mongo
* @param objectId
*/
public void deleteById(ObjectId objectId){
BasicDBObject query = new BasicDBObject("_id",objectId);
collection.remove(query);
}
/*
* update the value of key in json string. First the object is found using "_id"
*/
public boolean update(String key,String value,ObjectId objectId){
BasicDBObject query = new BasicDBObject("_id",objectId);
DBObject dbObject = collection.findOne(query);
if(dbObject != null){
DBObject newObject = new BasicDBObject(key, value);
DBObject oldObject = (DBObject) dbObject.get(key);
if(oldObject != null){
collection.update(dbObject,new BasicDBObject("$set",new BasicDBObject(key,value)));
return true;
}
}
return false;
}
}
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