在連結前，需要啟動mongoDB服務端，並在java專案中匯入fastjson和mongo-java-driver包

package com.mwc.test;
import java.net.UnknownHostException;
import java.util.ArrayList;
import java.util.List;
import com.alibaba.fastjson.JSON;
import com.mongodb.BasicDBObject;
import com.mongodb.DB;
import com.mongodb.DBCollection;
import com.mongodb.DBCursor;
import com.mongodb.DBObject;
import com.mongodb.MongoClient;
public class Mongoooo {
	public static DBCollection utill(String dbname,String colname) {
		try {
			//獲得連結物件
			MongoClient mongoClient=new MongoClient("127.0.0.1",27017);
			//獲得資料庫物件
			DB db=mongoClient.getDB(dbname);
			//獲取集合名
			DBCollection dbCollection=db.getCollection(colname);
			return dbCollection;
		} catch (UnknownHostException e) {
			e.printStackTrace();
			return null;
		}
		
	}
	/**
	 * 查詢集合
	 * @param collname 集合名
	 */
	public void selectt(String collname) {
		DBCollection db1=utill("qly", collname);
		DBObject dbObject=new BasicDBObject();
		DBCursor dbCursor=db1.find();
		List<User> ll=new ArrayList<User>();
		for(DBObject dbObject2:dbCursor) {
			//轉化為json串
			String ss=JSON.toJSONString(dbObject2);
			//轉化為user物件
			User user=JSON.parseObject(ss,User.class);
			ll.add(user);
			System.out.println(user);
		}
	}
	/**
	 * 新增
	 * @param collname  集合名
	 * @param dbObject  資料
	 * @return
	 */
	public void insertt(String collname,DBObject dbObject) {
		DBCollection db2=utill("qly", collname);
		db2.insert(dbObject);
		System.out.println("新增成功！");
	}
	/**
	 * 修改
	 * @param collname 集合名
	 * @param dbObject1  條件
	 * @param dbObject2  修改的資料
	 */
	public void updatee(String collname,DBObject dbObject1,DBObject dbObject2) {
		DBCollection db3=utill("qly", collname);
		db3.update(dbObject1, dbObject2, false, true);
		System.out.println("修改成功！");
	}
	/**
	 * 刪除
	 * @param collname 集合名
	 * @param dbObject 條件
	 */
	public void deletee(String collname,DBObject dbObject) {
		DBCollection db4=utill("qly", collname);
		db4.remove(dbObject);
		System.out.println("修改成功!");
	}
	public static void main(String[] args) {
		DBObject dbb1=new BasicDBObject();
		DBObject dbb2=new BasicDBObject();
		Mongoooo mongoooo=new Mongoooo();
		//查詢user集合
		mongoooo.selectt("user");
		//新增資料到user集合中
		dbb1.put("name", "qly");
		dbb1.put("age", 22);
		mongoooo.insertt("user", dbb1);
		//刪除一條資料
		dbb2.put("name", "qly1");
		mongoooo.deletee("user", dbb2);
		//修改一條資料
		DBObject dbb4=new BasicDBObject();
		DBObject dbb5=new BasicDBObject();
		dbb4.put("name", "qly");
		DBObject dbb3=new BasicDBObject();
		dbb3.put("age", 10);
		dbb5.put("$set", dbb3);
		mongoooo.updatee("user", dbb4, dbb5);
		
	}
}