import com.mongodb.Mongo; import com.mongodb.DBCollection; import com.mongodb.BasicDBObject; import com.mongodb.DBObject; import com.mongodb.DBCursor; import com.mongodb.MongoAdmin; Mongo db = new Mongo(“mydb”); Mongo db = new Mongo(“localhost”, “mydb”); Mongo db = new Mongo(“localhost”, 27017, “mydb”); boolean auth = db.authenticate(userName, password); //每个数据库都存在零个或多个集合 Set colls = db.getCollectionNames(); for(String s : colls){ System.out.println(s); } //查询 BasicDBObject query = new BasicDBObject(); query.put(“i”, new BasicDBObject(“$gt”, 20).append(“$lte”, 30)); cur = coll.find(query); while(cur.hasNext()){ System.out.println(cur.next()); }