mongodb学习(java操作mongodb)

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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();//          for (String name : dataBases) {//              System.out.println(name);//          }            //创建连接数据库(mydb)的连接            DB db =  mongo.getDB("mydb");            //查询mydb中所有的集合名称            Set<String>set =  db.getCollectionNames();//          for (String collectionName : set) {//              System.out.println(collectionName);//          }            //查询students集合中的所有数据            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));//          while (dbCursor.hasNext()) {//              DBObject object =  dbCursor.next();//              System.out.println(object.get("name"));//得到name字段的值//          }        } 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");List<String>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

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