I was trying to get all the documents from a collection in mongoDB , I am using spring.
MongoTemplate mongoOperation = SpringMongoConfig1.mongoTemplate()
Here in monngoOperation I did not find any method which returns all the docs from a collection .
can anyone help in this ?
If you want to find all the documents of JavaDocumentName(any collection name in java)
List<JavaDocumentName> listRes = mongoOperation.findAll(JavaDocumentName.class);
You can do like this:
//If you don't need connection's configures. i.e. your mongo is in you localhost at 127.0.0.1:27017
MongoClient cliente = new MongoClient(); //to connect into a mongo DB
MongoDatabase mongoDb = client.getDatabase("DBname"); //get database, where DBname is the name of your database
MongoCollection<Document> robosCollection = mongoDb.getCollection("collectionName"); //get the name of the collection that you want
MongoCursor<Document> cursor = robosCollection.find().cursor();//Mongo Cursor interface implementing the iterator protocol
cursor.forEachRemaining(System.out::println); //print all documents in Collection using method reference
Related
I am trying to pass a hint on an aggregate in MongoDB Java Driver 3.6.3. The aggregate API allows for adding a hint as in:
MongoCollection<Document> coll = database.getCollection("myCollection")
ArrayList<BasicDBObject> docList = new ArrayList<BasicDBObject>();
BasicDBObject hint = new BasicDBObject("$hint","reportjob_customerId_1_siiDocumentAttributes.deleted_1");
MongoCursor<Document> cursor = coll.aggregate(docList).hint(hint).allowDiskUse(batchContext.isAllowDiskUse()).iterator();
I've tried with $hint and hint, but Mongo always returns Command failed with error -1: 'unrecognized field 'hint'
How do I properly send the hint on the aggregate call?
Looks like there is no support to pass the index name directly to hint. So you have pass the index creation document to the hint which you can get by name and use key to get the index document.
MongoCollection<Document> coll = database.getCollection("myCollection");
Bson index = coll.listIndexes().into(new ArrayList<>()).stream().filter(item -> item.getString("name").equals("reportjob_customerId_1_siiDocumentAttributes.deleted_1")).findFirst().get().getString("key");
List<BasicDBObject> docList = new ArrayList<BasicDBObject>();
MongoCursor<Document> cursor = coll.aggregate(docList).hint(index).allowDiskUse(batchContext.isAllowDiskUse()).iterator();
Legacy driver had support for both index name and document.
MongoClient client = new MongoClient();
DB database = client.getDB("myDatabase");
DBCollection coll = database.getCollection("myCollection");
List<BasicDBObject> docList = new ArrayList<BasicDBObject>();
AggregationOptions options = AggregationOptions.builder().allowDiskUse(batchContext.isAllowDiskUse()).build();
DBCursor dbCursor = ((DBCursor) coll.aggregate(docList, options)).hint("reportjob_customerId_1_siiDocumentAttributes.deleted_1");
You can create a jira to have the option to pass index name in the new driver here
I want to add data in right collection considering by name. The code below is defining well. collection(db,name) returns the name of collection. But when I want to save the collection name via rightCollection = collections(db, name) and inserting it as db.rightCollection.insert({"1" : "Righ collection"}). Pymongo is creating the collection under name rightCollection not Peter. I want to insert data in Peter. Why is it so? Can I resolve it?
from pymongo import MongoClient
def collections(db,name):
if(name is 'Peter'):
return db.Peter
client = MongoClient()
db = client.myDB
name="Peter"
rightCollection = collections(db, name)
db.rightCollection.insert({"1" : "Righ collection"})
Using pymongo 3.2.2, you don't need the collections function, you can just use the collection name directly:
from pymongo import MongoClient
client = MongoClient()
db = client.myDB
db.Peter.insert_one({'1': 'Right collection'})
That should insert the document {'1': 'Right collection} into collection Peter under database myDB. To verify that the data is inserted correctly, you can use the mongo shell:
> use myDB
> db.Peter.find()
{ "_id": ObjectId("57df7a4f98e914c98d540992"), "1": "Right collection" }
Or, if you need the name Peter to be defined in a variable, you can do:
from pymongo import MongoClient
client = MongoClient()
db = client.myDB
coll_name = 'Peter'
db[coll_name].insert_one({'1': 'Right collection'})
I want to copy the contents from one collection to another.
in mongod this can be done:
db.tempMongoItem.find().forEach( function(x){db.mongoItem.insert(x)} )
Using Java Mongo Driver, I try:
DB db = mongoClient.getDB("mydb")
CommandResult result = db.command("db.tempMongoItem.find().forEach( function(x){db.mongoItem.insert(x)} )")
But I get:
result = [serverUsed:localhost:27017, ok:0.0, errmsg:no such cmd: db.tempMongoItem.find().forEach( function(x){db.mongoItem.insert(x)} ), code:59, bad cmd:[db.tempMongoItem.find().forEach( function(x){db.mongoItem.insert(x)} ):true]]
Any ideas?
You need to emulate the same thing JS is doing in Java, which means getting a cursor and iterating over it, inserting each document into new collection.
Something like this (coll is current, coll2 is new collection):
DBCursor cursor = coll.find();
try {
while(cursor.hasNext()) {
coll2.insert(cursor.next());
}
} finally {
cursor.close();
}
Both coll and coll2 are assumed to be DBCollection type.
Since it appears you are copying within the same DB, there is another way to do this if you are using 2.6 MongoDB using aggregation framework $out stage:
db.collection.aggregate({"$out":"newCollection"});
Note that this is limited to outputting into the same DB that original collection is in.
The following JAVA code will copy the collection from source to destination for a given database name (using mongodb-driver 3.0.4)
/** Clone a collection.
*
* #param fromCollectionName - The name of collection to be cloned
* #param toCollectionName - The name of the cloned collection
* #param dbName - The name of the database
*/
public void cloneCollection(String fromCollectionName, String toCollectionName, String dbName) throws MongoException {
MongoCollection toCol = this.getCollection(toCollectionName, dbName);
if (toCol != null) {
throw new MongoException("The destination collection already exists.");
}
List<Document> ops = new ArrayList<>();
ops.add(new Document("$out",toCollectionName));
MongoCollection sourceCollection = this.getCollection(fromCollectionName, dbName);
sourceCollection.aggregate(ops);
}
public MongoCollection getCollection(String collection, String dbName) {
MongoClient mongo = new MongoClient(new ServerAddress("localhost", Integer.parseInt(port)));
MongoDatabase database = mongo.getDatabase(dbName);
return curdb.getCollection(collection);
}
Please note that this will not copy over the indices that you have created in source collection. You will have to copy the indices seperately
Following up on Asya's response, you can use Java 8 Lambda functions to do:
collSource.find().forEach((Block<Document>) collTarget::insertOne);
I am creating a collection in MongoDB in the following way and I want to create a 2dsphere index on location field of this collection from Java code. But I am not able to do so.
collection.ensureIndex() method expects a DBObject as a parameter but I cannot pass location to it.
How do I create collection.ensureIndex({"location" : "2dsphere"}) in Java code?
MongoDB allows me to do so in command prompt. But, I want to index it through code written in Java.
BasicDBObject doc = new BasicDBObject("attr1", nextLine[0])
.append("attr2", nextLine[1])
.append("edge-metro-code", nextLine[6])
.append("location", new BasicDBObject("type", "Point")
.append("coordinates",latLong))
.append("attr3", nextLine[9])
.append("attr4", nextLine[10])
ensureIndex() has been deprecated now. You should use createIndex() instead:
MongoClient mongoClient = new MongoClient();
DBCollection test = mongoClient.getDB("testdb").getCollection("test");
test.createIndex(new BasicDBObject("location","2dsphere"));
You should construct a new DBObject that represents your index. See the code bellow:
DBObject index2d = BasicDBObjectBuilder.start("location", "2dsphere").get();
DBCollection collection = new Mongo().getDB("yourdb").getCollection("yourcollection");
collection.ensureIndex(index2d);
This is my java class that will connect to Mongo DB and fetch the Data .
public class Test
{
public static void main(String args[])
{
DBCursor cursor = null;
DBCollection coll = null;
BasicDBObject query = new BasicDBObject();
String symbol = args[0];
query.put("symbol", "" + symbol);
cursor = coll.find(query);
int count = coll.find(query).count();
}
}
My question is , is it possible to know how many queries are made to the Mongo DB through this program ??
What i want to know is that whether two calls are made to the Mongo DB with this below statements
cursor = coll.find(query);
int count = coll.find(query).count();
Is it possible to know if two calls are amde to the Mongo DB with the above ??
You can use the MongoDB profiling to see the queries that are executed against the server. See the MongoDB documentation for further information: http://docs.mongodb.org/manual/reference/method/db.setProfilingLevel/
In short words: Execute db.setProfilingLevel(2) in your shell and look into the system.profile collection on your server.
If that is the only program connecting to MongoDB you can turn on profiling: http://docs.mongodb.org/manual/tutorial/manage-the-database-profiler/
You would turn profiling upto its max level (2), however if this is just one application of many then there might be (as in PHP) a MongoLog class ( http://php.net/manual/en/class.mongolog.php ) you could use.