java操作Mongodb数据库

1. 首先，从MongoDB的官方网站获取java的驱动mongo-2.7.2.jar，并把它放入工程的classpath中。

2. 如果是连接到本地数据库，可以采用如下三种方式：

    Mongo mongo = new Mongo();

    Mongo m = new Mongo( "localhost" );
    Mongo m = new Mongo( "localhost" , 27017 );
3.获取数据库，如果不存在该数据库，将会被自动创建。
   DB db = mongo.getDB("localdb");

4.代码示例：

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 TestConnect {

	public static void main(String[] args) throws UnknownHostException, MongoException {
		Mongo mongo = new Mongo();
		DB db = mongo.getDB("localdb");
		// boolean auth = db.authenticate("", "");
		
		// 获取集合名称列表
		Set<String> collections = db.getCollectionNames();
		for (String collc : collections)
		{
			System.out.println(collc);
		}
		
		// 获取指定集合
		DBCollection coll = db.getCollection("user");
		BasicDBObject obj = new BasicDBObject();
		obj.put("name", "lisi");
		obj.put("age", "20");
		coll.insert(obj);
		
		// 查找对象
		DBObject object = coll.findOne();
		System.out.println(object);
		
		// 批量插入
		for (int i=0; i<5; i++)
		{
			coll.insert(new BasicDBObject().append("name", "name" + i).append("age", i));
		}
		
		// 统计数据
		System.out.println(coll.getCount());
		
		// 查询并迭代所有对象
		DBCursor cursor = coll.find();
		while (cursor.hasNext())
		{
			System.out.println(cursor.next());
		}
		
		// 查询子集
		BasicDBObject query = new BasicDBObject();
		query.put("name", "lisi");
		DBCursor queryResult = coll.find(query);
		while (queryResult.hasNext())
		{
			System.out.println(queryResult.next());
		}
	}
}