JAVA对mongodb的基本操作

public class test3 {
//连接数据库(不需要验证，用于测试连接本地的mongodb)
    public static MongoDatabase getDatabase(String DbName){
        MongoClient mongoClient = new MongoClient("localhost",27017);
        MongoDatabase mongoDatabase = mongoClient.getDatabase(DbName);
return mongoDatabase;
    }
//连接数据库（需要密码验证，没写）
    public static MongoDatabase getDatabase(String DbName,String UserName,String PassWord){
return null;
    }
public static void insertDemo(){
        MongoCollection col = getDatabase("mydb1").getCollection("test");
//准备数据，将数据插入存入文档中
        Document doc1 = new Document();
        doc1.append("name","yj");
        doc1.append("age","12");
//将文档插入到mongodb中
        col.insertOne(doc1);
//插入多个数据
        List<Document> DocList = new ArrayList<>();
for(int i =0 ; i<10 ; i++){
            Document document = new Document();
            document.append("name","yj");
            document.append("age",i);
            DocList.add(document);
        }
        col.insertMany(DocList);
    }
public static void deleteDemo(){
        MongoCollection col = getDatabase("mydb1").getCollection("test");
//删除条件
        Bson filter = Filters.eq("name","yj9");
//删除单个文档
//        col.deleteOne(filter);
        //删除满足条件的所有文档
        col.deleteMany(filter);
    }
public static void updateDemo(){
        MongoCollection col = getDatabase("mydb1").getCollection("test");
        Bson filter = Filters.eq("name","yj1");
//$set修改器
        Document document = new Document("$set",new Document("name","yyyyy"));
//        col.updateOne(filter,document);
        col.updateMany(filter,document);
    }
public static void selectDemo(){
        MongoCollection col = getDatabase("mydb1").getCollection("test");
        FindIterable findIterable = col.find();
        MongoCursor cursor = findIterable.iterator();
while(cursor.hasNext()){
             Document document = (Document) cursor.next();
            System.out.println(document.getString("name")+ " is "+document.get("age"));
        }
    }
public static void selectDemo2(){
/**
         * 1.多个条件查询
         * 2.根据ObjectId()大小查询
         */
        BasicDBObject obj = new BasicDBObject();
//第一个用put，后面的都有append，防止被覆盖
        obj.put("name","yj");
//$gt 大于  ； $lte  小于
        obj.append("_id",new BasicDBObject("$gt",new ObjectId("5c9c8a0f232b2e0de002a02d")));
        MongoCollection col = getDatabase("mydb1").getCollection("test");
        FindIterable findIterable = col.find(obj).limit(5);
        MongoCursor<Document> mongoCursor = findIterable.iterator();
while(mongoCursor.hasNext()){
            Document document = mongoCursor.next();
            System.out.println(document.getString("name")+ " is "+document.get("age"));
        }
    }
public static void main(String[] args){
    }
}