mongoDB用java实现增删改查

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();
		}
	}
}

{ "_id" : { "$oid" : "5454fa4458404d12637d418c"} , "name" : "Hannah" , "no" : 2}
The Search Query has Executed!

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");
    }
}