首先添加mongodb的驱动包

并开启了mongodb的服务

package com.zzq.test;

import java.net.UnknownHostException;

import com.mongodb.DB;
import com.mongodb.DBCollection;
import com.mongodb.DBCursor;
import com.mongodb.Mongo;
import com.mongodb.MongoException;
import com.mongodb.util.JSON;

public class MongDBTest {
public static void main(String[] args) throws UnknownHostException, MongoException {
 
  Mongo mg = new Mongo("localhost", 27017);
     //查询所有的Database
     for (String name : mg.getDatabaseNames()) {
         System.out.println("dbName: " + name);
     }
    
     DB db = mg.getDB("mircroblog");
     //查询所有的聚集集合
     for (String name : db.getCollectionNames()) {
         System.out.println("collectionName: " + name);
     }
    
     DBCollection users = db.getCollection("citizens");
    
     //查询所有的数据
     DBCursor cur = users.find();
     while (cur.hasNext()) {
         System.out.println(cur.next());
     }
     System.out.println(cur.count());
     System.out.println(cur.getCursorId());
     System.out.println(JSON.serialize(cur));

   }

}