mongoDB与java简单链接

在链接前，需要启动mongoDB服务端，并在java项目中导入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 {
			//获得链接对象
			MongoClient mongoClient=new MongoClient("127.0.0.1",27017);
			//获得数据库对象
			DB db=mongoClient.getDB(dbname);
			//获取集合名
			DBCollection dbCollection=db.getCollection(colname);
			return dbCollection;
		} catch (UnknownHostException e) {
			e.printStackTrace();
			return null;
		}
		
	}
	/**
	 * 查询集合
	 * @param collname 集合名
	 */
	public void selectt(String collname) {
		DBCollection db1=utill("qly", collname);
		DBObject dbObject=new BasicDBObject();
		DBCursor dbCursor=db1.find();
		List ll=new ArrayList();
		for(DBObject dbObject2:dbCursor) {
			//转化为json串
			String ss=JSON.toJSONString(dbObject2);
			//转化为user对象
			User user=JSON.parseObject(ss,User.class);
			ll.add(user);
			System.out.println(user);
		}
	}
	/**
	 * 添加
	 * @param collname  集合名
	 * @param dbObject  数据
	 * @return
	 */
	public void insertt(String collname,DBObject dbObject) {
		DBCollection db2=utill("qly", collname);
		db2.insert(dbObject);
		System.out.println("添加成功！");
	}
	/**
	 * 修改
	 * @param collname 集合名
	 * @param dbObject1  条件
	 * @param dbObject2  修改的数据
	 */
	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！");
	}
	/**
	 * 删除
	 * @param collname 集合名
	 * @param dbObject 条件
	 */
	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();
		//查询user集合
		mongoooo.selectt("user");
		//添加数据到user集合中
		dbb1.put("name", "qly");
		dbb1.put("age", 22);
		mongoooo.insertt("user", dbb1);
		//删除一条数据
		dbb2.put("name", "qly1");
		mongoooo.deletee("user", dbb2);
		//修改一条数据
		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);
		
	}
}