Java操作MongoDB例子—增删改查

import java.net.UnknownHostException;
import java.util.Iterator;
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 MongoMain {
	
	static DB db = null;
	static DBCollection coll = null;
	
	static {
		 Mongo m = null;
		try {
			//m = new Mongo();//默认本地
			//m = new Mongo("127.0.0.1");//默认端口
			m = new Mongo("127.0.0.1",27017);
		} catch (UnknownHostException e) {
			e.printStackTrace();
		} catch (MongoException e) {
			e.printStackTrace();
		}
		
		//获取名为 test 的数据库，不存在的情况下创建
		db = m.getDB("test");
		
		//登录数据库（用户名:test，密码:test）
		boolean auth = db.authenticate("test", "test".toCharArray());
		if(auth){
			//只有admin中的用户才有此权限(show dbs)
			//获取所有数据库，不显示无collection的db
			//System.out.println("所有数据库名："+m.getDatabaseNames());
			
			//获取名为 user 的collection(相当于表)，不存在的情况下创建
			coll = db.getCollection("user");
		}else{
			System.out.println("登录失败!");
		}
	}
	
	public static void main(String[] args) {
		MongoMain test = new MongoMain();
		if(coll!=null){
			test.saveData();
			test.searchData();
			test.updateData();
			test.deleteData();
		}
	}

	/**
	 * 保存数据
	 */
	public void saveData(){
		//录入学生1的信息
		BasicDBObject stu1 = new BasicDBObject();
		stu1.put("name", "jack");
		stu1.put("age", "25");
		BasicDBObject sight1 = new BasicDBObject();
		sight1.put("left", 1.5);
		sight1.put("right", 1.2);
		stu1.put("sight", sight1);
		
		//录入学生2的信息
		BasicDBObject stu2 = new BasicDBObject();
		stu2.put("name", "lucy");
		stu2.put("age", "22");
		BasicDBObject sight2 = new BasicDBObject();
		sight2.put("left", 1.0);
		sight2.put("right", 1.3);
		stu2.put("sight", sight2);
		
		//注意：不能直接对sight赋值{left:1.0,right:1.3}
		
		coll.insert(stu1);
		coll.insert(stu2);
	}
	
	/**
	 * 查询数据
	 */
	public void searchData(){
		System.out.println("=======================");
		//show collections
		//获取数据库下所有的collection，不显示无数据的collection
		Set<String> colls = db.getCollectionNames();
		showData(colls);
		
		System.out.println("=======================");
		
		//查询coll中全部记录 
		DBCursor ite = coll.find();  
		showData(ite);
		
		System.out.println("=======================");
		
		//获取第一条记录
		DBObject o = coll.findOne();
		System.out.println(o);
		
		System.out.println("=======================");
		
		//统计colletion的数据条数
		System.out.println(coll.getCount());
		
		System.out.println("=======================");
		
		//查询 name为jack的对象 
		BasicDBObject query = new BasicDBObject();
		query.put("name", "jack");
		DBCursor it = coll.find(query);  
		showData(it);
		
		System.out.println("=======================");
		
		//查询age小于30，age不等于20的对象 
		BasicDBObject query2 = new BasicDBObject();
		query2.put("age", new BasicDBObject("$lt", 30));
		query2.put("age", new BasicDBObject("$ne", 20));
		DBCursor it2 = coll.find(query2);  
		showData(it2);
	}
	
	/**
	 * 修改数据
	 */
	public void updateData(){
		BasicDBObject query = new BasicDBObject();
		query.put("name", "lucy");
		//这里的new_info对象一定要是find出的而不是new的，否则多字段的情况下就会丢失其它字段信息
		DBObject new_info = coll.findOne(query);
		
		//方法一（缺点，必须把2个值都put进去）
		BasicDBObject sight = new BasicDBObject();
		sight.put("left", 1.3);
		sight.put("right", 1.3);
		new_info.put("sight", sight);
		
		//方法二（优点，只需设置要修改的字段的值）
		DBObject obj = (DBObject)new_info.get("sight");
		obj.put("right", 1.5);
		
		coll.update(query, new_info);
	}
	
	/**
	 * 删除数据
	 */
	public void deleteData(){
		BasicDBObject data = new BasicDBObject();
		//删除名称为lucy的记录
		data.put("name", "lucy");
		//传入[空实例]删除所有
		coll.remove(data);
	}
	
	/**
	 * 遍历显示结果
	 * @param result
	 */
	@SuppressWarnings("rawtypes") 
	public void showData(Iterable result){
		Iterator it = result.iterator(); 
		while(it.hasNext())  
		{  
			System.out.println(it.next());  
		}  
    }  
}

 

 Java操作MongoDB，下面是一个完整的例子。本实例需导入mongo-2.5.3.jar