mongodb学习(java操作mongodb)

在mysql，sqlserver和orcale中都提供了java的驱动，为我们封装好了很多的接口，在java层调用起来了是很方便的。在mongodb中同样为我们提供了这样的驱动。和mysql一样，我们只需将下载好的mongo.jar进行buildPath即可，就可以调用其为我们封装的接口了。

查询已有的数据 try {//建立一个mongo的连接数据库的对象Mongo mongo = new Mongo(“127.0.0.1:27017”);//查询所有数据库的明后才能List<String>dataBases = mongo.getDatabaseNames();DB db = mongo.getDB(“mydb”);//查询mydb中所有的集合名称Set<String>set = db.getCollectionNames();DBCollection dbCollection = db.getCollection(“students”);DBCursor dbCursor = dbCollection.find();//将该cursor序列化成json对象System.out.println(JSON.serialize(dbCursor));} catch (UnknownHostException e) {e.printStackTrace();} catch (MongoException e) {e.printStackTrace();}新建一个”mongnew”数据库，并且插入一条数据//建立一个mongo的连接数据库的对象Mongo mongo = new Mongo(“127.0.0.1:27017”);//创建一个mongonew数据库DB db = mongo.getDB(“mongonew”);//创建一个集合，，并且插入一条记录DBObject dbObject = new BasicDBObject();dbObject.put(“age”,22);dbObject.put(“name”,”张三”);fruits = new ArrayList<>();fruits.add(“orange”);fruits.add(“apple”);fruits.add(“water”);dbObject.put(“fruits”,fruits);DBCollection teacherCollection =db.getCollection(“teachers”);//得到teacher集合teacherCollection.insert(dbObject);//插入dbObject批量插入数据List<DBObject>dbList = new ArrayList<>();DBObject object = null;for (int i = 1; i < 4; i++) {object = new BasicDBObject();object.put(“age”,i);object.put(“name”,”aName”+i);dbList.add(object);}DBCollection teacherCollection2 = db.getCollection(“teachers”);//得到teacher集合teacherCollection2.insert(dbList);//批量插入dbObject，参数是一个list集合根据条件删除数据

删除age=3的数据

DBCollection dbCollection3 = db.getCollection(“teachers”);dbCollection3.remove(new BasicDBObject(“age”,3));给集合批量增加属性DBCollection dbCollection4 = db.getCollection(“teachers”);DBObject updateObject = new BasicDBObject();updateObject.put(“$set”,new BasicDBObject(“passworld”,”123″));dbCollection4.update(new BasicDBObject(),updateObject,false,true);只查询某些字段DBCollection dbCollection5 = db.getCollection(“teachers”);DBObject keys = new BasicDBObject();keys.put(“_id”,false);keys.put(“name”,true);keys.put(“passworld”,true);DBCursor dbCursor = dbCollection5.find(null,keys);DBObject dbObjec = null;while (dbCursor.hasNext()) {dbObjec = dbCursor.next();System.out.println(JSON.serialize(dbObjec));}分页查询//分页查询DBCollection dbCollection6 = db.getCollection(“teachers”);DBCursor cursor = dbCollection6.find().limit(2).skip(0);DBObject dbObject = null;while (cursor.hasNext()) {dbObject = cursor.next();System.out.println(JSON.serialize(dbObject));}分页查询指定的键DBCollection dbCollection6 = db.getCollection(“teachers”);DBObject keys = new BasicDBObject();keys.put(“_id”,false);keys.put(“name”,true);keys.put(“passworld”,true);DBCursor cursor = dbCollection6.find(null,keys).limit(2).skip(0);DBObject dbObject = null;while (cursor.hasNext()) {dbObject = cursor.next();System.out.println(JSON.serialize(dbObject));}

源码下载

勇敢的冷静的理智的去接受失败，有时不但是必要的，而且是很有必要的。