I want to delete all documents in a collection in java. Here is my code:
MongoClient client = new MongoClient("10.0.2.113" , 27017); MongoDatabase db = client.getDatabase("maindb"); db.getCollection("mainCollection").deleteMany(new Document()); Is this the correct way to do this?
I am using MongoDB 3.0.2
Using API >= 3.0:
MongoClient mongoClient = new MongoClient("127.0.0.1" , 27017); MongoDatabase db = mongoClient.getDatabase("maindb"); db.getCollection("mainCollection").deleteMany(new Document()); To drop the collection (documents and indexes) you still can use:
db.getCollection("mainCollection").drop(); see https://docs.mongodb.org/getting-started/java/remove/#remove-all-documents
To remove all documents use the BasicDBObject or DBCursor as follows:
MongoClient client = new MongoClient("10.0.2.113" , 27017); MongoDatabase db = client.getDatabase("maindb"); MongoCollection collection = db.getCollection("mainCollection") BasicDBObject document = new BasicDBObject(); // Delete All documents from collection Using blank BasicDBObject collection.deleteMany(document); // Delete All documents from collection using DBCursor DBCursor cursor = collection.find(); while (cursor.hasNext()) { collection.remove(cursor.next()); } 
If you want to remove all documents in collection then used below code :
db.getCollection("mainCollection").remove(new BasicDBObject()); Or If you want to drop whole collection then used this :
db.getCollection("mainCollection").drop(); 
For newer mongodb drivers you can use FindIterable to remove all documents in collection.
FindIterable<Document> findIterable = collection.find(); for (Document document : findIterable) { collection.deleteMany(document); } 