package mongo;import java.net.UnknownHostException;import com.mongodb.BasicDBObject;import com.mongodb.DB;import com.mongodb.DBCollection;import com.mongodb.DBCursor;import com.mongodb.Mongo;import com.mongodb.MongoException;public class connection {	public static void main(String[] args){		try{			Mongo m = new Mongo("localhost", 27017);			DB db = m.getDB("company");			DBCollection collection = db.getCollection("employees");			BasicDBObject employee = new BasicDBObject();			employee.put("name", "Hannah");			employee.put("no", 2);			collection.insert(employee);			BasicDBObject searchEmployee = new BasicDBObject();			searchEmployee.put("no", 2);			DBCursor cursor = collection.find(searchEmployee);			while(cursor.hasNext()){				System.out.println(cursor.next());			}			System.out.println("The Search Query has Executed!"); 		}catch(UnknownHostException e){			e.printStackTrace();		}catch(MongoException e){			e.printStackTrace();		}	}}

import java.net.UnknownHostException;  import java.util.Set;    import com.mongodb.BasicDBObject;  import com.mongodb.DB;  import com.mongodb.DBCollection;  import com.mongodb.DBCursor;  import com.mongodb.DBObject;  import com.mongodb.Mongo;  import com.mongodb.MongoException;    public class Test {        /**      * @author gaogao      * @param args      * @throws MongoException      * @throws UnknownHostException      */      public static void main(String[] args) throws UnknownHostException,              MongoException {          // TODO Auto-generated method stub          // 连接本地数据库          Mongo m = new Mongo();          // 创建名为new_test_db的数据库          DB db = m.getDB("new_test_db");          // 获取new_test_db中的集合（类似于获取关系数据库中的表）          Set<String> cols = db.getCollectionNames();          // 打印出new_test_db中的集合，这里应当为null          for (String s : cols) {              System.out.println(s);          }          // 创建一个叫做"new_test_col"的集合          DBCollection collection = db.getCollection("new_test_col");          // 初始化一个基本DB对象，最终插入数据库的就是这个DB对象          BasicDBObject obj = new BasicDBObject();          // 放入几个键值对          obj.put("from", "搞搞");          obj.put("to", "宝宝");          obj.put("subject", "狗子爱宝子");          //插入对象          collection.insert(obj);          //查看一条记录，findOne()=find().limit(1);          DBObject dbobj=collection.findOne();          //打印出刚才插入的数据          System.out.println(dbobj);          //现在我们来插入9条{ranking:i}的数据          for(int i=0;i<9;i++){              collection.insert(new BasicDBObject().append("ranking", i));          }          //打印集合中的数据总数，这里应当输出10          System.out.println(collection.getCount());          //下面我们来遍历集合，find()方法返回的是一个游标(cursor)，这里的概念和关系数据库很相似          DBCursor cursor=collection.find();          //然后我们使用这个游标来遍历集合          while(cursor.hasNext()){              System.out.println(cursor.next());          }          //下面来看一些略复杂一点的查询技巧，第一个，简单的条件查询，查询ranking为1的记录          BasicDBObject query=new BasicDBObject();          query.put("ranking", 1);          cursor=collection.find(query);          while(cursor.hasNext()){              System.out.println(cursor.next());          }          //下面是更复杂的条件查询，查询ranking大于5小于9的记录          query=new BasicDBObject();          query.put("ranking", new BasicDBObject("$gt", 5).append("$lt", 9));          cursor=collection.find(query);          while(cursor.hasNext()){              System.out.println(cursor.next());          }          //最后删除我们的测试数据库          m.dropDatabase("new_test_db");      }  }