Example usage for com.mongodb.client MongoCollection countDocuments

Introduction

In this page you can find the example usage for com.mongodb.client MongoCollection countDocuments.

Prototype

long countDocuments();

Source Link

Document

Counts the number of documents in the collection.

Usage

From source file:tour.PojoQuickTour.java

License:Apache License

/**
 * Run this main method to see the output of this quick example.
 *
 * @param args takes an optional single argument for the connection string
 *///  ww  w  .  j  a v  a 2 s.  com
public static void main(final String[] args) {
    MongoClient mongoClient;

    if (args.length == 0) {
        // connect to the local database server
        mongoClient = MongoClients.create();
    } else {
        mongoClient = MongoClients.create(args[0]);
    }

    // create codec registry for POJOs
    CodecRegistry pojoCodecRegistry = fromRegistries(MongoClientSettings.getDefaultCodecRegistry(),
            fromProviders(PojoCodecProvider.builder().automatic(true).build()));

    // get handle to "mydb" database
    MongoDatabase database = mongoClient.getDatabase("mydb").withCodecRegistry(pojoCodecRegistry);

    // get a handle to the "people" collection
    MongoCollection<Person> collection = database.getCollection("people", Person.class);

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

    // make a document and insert it
    Person ada = new Person("Ada Byron", 20, new Address("St James Square", "London", "W1"));
    System.out.println("Original Person Model: " + ada);
    collection.insertOne(ada);

    // Person will now have an ObjectId
    System.out.println("Mutated Person Model: " + ada);

    // get it (since it's the only one in there since we dropped the rest earlier on)
    Person somebody = collection.find().first();
    System.out.println(somebody);

    // now, lets add some more people so we can explore queries and cursors
    List<Person> people = asList(
            new Person("Charles Babbage", 45, new Address("5 Devonshire Street", "London", "W11")),
            new Person("Alan Turing", 28, new Address("Bletchley Hall", "Bletchley Park", "MK12")),
            new Person("Timothy Berners-Lee", 61, new Address("Colehill", "Wimborne", null)));

    collection.insertMany(people);
    System.out.println("total # of people " + collection.countDocuments());

    System.out.println("");
    // lets get all the documents in the collection and print them out
    Block<Person> printBlock = new Block<Person>() {
        @Override
        public void apply(final Person person) {
            System.out.println(person);
        }
    };

    collection.find().forEach(printBlock);

    System.out.println("");
    // now use a query to get 1 document out
    somebody = collection.find(eq("address.city", "Wimborne")).first();
    System.out.println(somebody);

    System.out.println("");
    // now lets find every over 30
    collection.find(gt("age", 30)).forEach(printBlock);

    System.out.println("");
    // Update One
    collection.updateOne(eq("name", "Ada Byron"), combine(set("age", 23), set("name", "Ada Lovelace")));

    System.out.println("");
    // Update Many
    UpdateResult updateResult = collection.updateMany(not(eq("zip", null)), set("zip", null));
    System.out.println(updateResult.getModifiedCount());

    System.out.println("");
    // Replace One
    updateResult = collection.replaceOne(eq("name", "Ada Lovelace"), ada);
    System.out.println(updateResult.getModifiedCount());

    // Delete One
    collection.deleteOne(eq("address.city", "Wimborne"));

    // Delete Many
    DeleteResult deleteResult = collection.deleteMany(eq("address.city", "London"));
    System.out.println(deleteResult.getDeletedCount());

    // Clean up
    database.drop();

    // release resources
    mongoClient.close();
}

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