mongodb學習(java操作mongodb)

mongodb學習(java操作mongodb)

在mysql，sqlserver和orcale中都提供了java的驅動，為我們封裝好了很多的接口，在java層調用起來了是很方便的。在mongodb中同樣為我們提供了這樣的驅動。和mysql一樣，我們只需將下載好的mongo.jar進行buildPath即可，就可以調用其為我們封裝的接口了。

查詢已有的數據

    try {
            //建立一個mongo的連接數據庫的對象
            Mongo mongo = new Mongo("127.0.0.1:27017");
            //查詢所有數據庫的明後才能
            ListdataBases = mongo.getDatabaseNames();
//          for (String name : dataBases) {
//              System.out.println(name);
//          }
            //創建連接數據庫(mydb)的連接
            DB db =  mongo.getDB("mydb");
            //查詢mydb中所有的集合名稱
            Setset =  db.getCollectionNames();
//          for (String collectionName : set) {
//              System.out.println(collectionName);
//          }
            //查詢students集合中的所有數據
            DBCollection dbCollection = db.getCollection("students");
            DBCursor dbCursor = dbCollection.find();
            //將該cursor序列化成json對象
            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();
        }

新建一個”mongnew”數據庫，並且插入一條數據

//建立一個mongo的連接數據庫的對象
Mongo mongo = new Mongo("127.0.0.1:27017");
//創建一個mongonew數據庫
DB db = mongo.getDB("mongonew");
//創建一個集合，並且插入一條記錄
DBObject dbObject = new BasicDBObject();
dbObject.put("age",22);
dbObject.put("name","張三");
Listfruits = 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

批量插入數據

ListdbList = 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，參數是一個list集合

根據條件刪除數據

刪除age=3的數據

DBCollection dbCollection3 = db.getCollection("teachers");
dbCollection3.remove(new BasicDBObject("age",3));

給集合批量增加屬性

DBCollection dbCollection4 = db.getCollection("teachers");
DBObject updateObject = new BasicDBObject();
updateObject.put("$set",new BasicDBObject("passworld","123"));
dbCollection4.update(new BasicDBObject(),updateObject,false,true);

只查詢某些字段

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));
}

分頁查詢

//分頁查詢
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));
}

分頁查詢指定的鍵

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));
}