Example usage for com.mongodb DBCollection findOne

Introduction

In this page you can find the example usage for com.mongodb DBCollection findOne.

Prototype

@Nullable
public DBObject findOne(final Object id)

Source Link

Document

Get a single document from collection by '_id'.

Usage

From source file:teste.mongo.example.QuickTourAdmin.java

License:Apache License

public static void main(String[] args) throws Exception {

    // connect to the local database server 
    MongoClient mongoClient = new MongoClient();

    /*//from  w w w  .j  a  v  a  2s .c  om
    // Authenticate - optional
    MongoCredential credential = MongoCredential.createMongoCRCredential(userName, database, password);
    MongoClient mongoClient = new MongoClient(new ServerAddress(), Arrays.asList(credential));
    */

    System.out.println("##### DataBaseInitial");
    // get db names
    for (String s : mongoClient.getDatabaseNames()) {
        System.out.println(s);
    }

    // get a db
    DB db = mongoClient.getDB("mydb");

    System.out.println("##### With new DataBase MYDB");
    // do an insert so that the db will really be created.  Calling getDB() doesn't really take any
    // action with the server 
    db.getCollection("testcollection").insert(new BasicDBObject("i", 1));
    for (String s : mongoClient.getDatabaseNames()) {
        System.out.println(s);
    }

    // drop a database
    mongoClient.dropDatabase("mydb");

    System.out.println("##### DataBase drop MYDB");
    for (String s : mongoClient.getDatabaseNames()) {
        System.out.println(s);
    }

    // create a collection
    db = mongoClient.getDB("mydb");
    db.createCollection("testCollection", new BasicDBObject("capped", true).append("size", 1048576));

    System.out.println("##### ListAllCollection MYDB");
    // List all collections
    for (String s : db.getCollectionNames()) {
        System.out.println(s);
    }

    // Dropping a collection
    DBCollection testCollection = db.getCollection("testCollection");
    testCollection.drop();
    System.out.println("##### ListAllCollection MYDB - Drop testCollection");
    System.out.println(db.getCollectionNames());

    /* Indexes */
    // get a collection object to work with
    DBCollection coll = db.getCollection("testCollection");

    // drop all the data in it
    coll.drop();

    // create an index on the "i" field
    coll.createIndex(new BasicDBObject("i", 1));

    // Geospatial query
    coll.createIndex(new BasicDBObject("loc", "2dsphere"));

    BasicDBList coordinates = new BasicDBList();
    coordinates.put(0, -73.97);
    coordinates.put(1, 40.77);
    coll.insert(new BasicDBObject("name", "Central Park")
            .append("loc", new BasicDBObject("type", "Point").append("coordinates", coordinates))
            .append("category", "Parks"));

    coordinates.put(0, -73.88);
    coordinates.put(1, 40.78);
    coll.insert(new BasicDBObject("name", "La Guardia Airport")
            .append("loc", new BasicDBObject("type", "Point").append("coordinates", coordinates))
            .append("category", "Airport"));

    // Find whats within 500m of my location
    BasicDBList myLocation = new BasicDBList();
    myLocation.put(0, -73.965);
    myLocation.put(1, 40.769);
    DBObject myDoc = coll.findOne(new BasicDBObject("loc", new BasicDBObject("$near",
            new BasicDBObject("$geometry", new BasicDBObject("type", "Point").append("coordinates", myLocation))
                    .append("$maxDistance", 500))));
    System.out.println(myDoc.get("name"));

    // create a text index on the "content" field
    coll.createIndex(new BasicDBObject("content", "text"));

    coll.insert(new BasicDBObject("_id", 0).append("content", "textual content"));
    coll.insert(new BasicDBObject("_id", 1).append("content", "additional content"));
    coll.insert(new BasicDBObject("_id", 2).append("content", "irrelevant content"));

    // Find using the text index
    BasicDBObject search = new BasicDBObject("$search", "textual content -irrelevant");
    BasicDBObject textSearch = new BasicDBObject("$text", search);
    int matchCount = coll.find(textSearch).count();
    System.out.println("Text search matches: " + matchCount);

    // Find using the $language operator
    textSearch = new BasicDBObject("$text", search.append("$language", "english"));
    matchCount = coll.find(textSearch).count();
    System.out.println("Text search matches (english): " + matchCount);

    // Find the highest scoring match
    BasicDBObject projection = new BasicDBObject("score", new BasicDBObject("$meta", "textScore"));
    myDoc = coll.findOne(textSearch, projection);
    System.out.println("Highest scoring document: " + myDoc);

    // list the indexes on the collection
    List<DBObject> list = coll.getIndexInfo();
    for (final DBObject o : list) {
        System.out.println(o);
    }

    // clean up
    mongoClient.dropDatabase("mydb");
    mongoClient.close();
}