通过读取配置文件，启动mongodb

　　在实际的项目中，经常利用mongodb数据库做缓存，mongodb的并发性比较高，所以对于快速存储、读取信息有很多优点。在项目中对于第一次的数据请求会直接访问数据库，而对于获得的信息通常都会在此时刻存入到mongodb中，下一次请求就不会再访问数据库而是直接在mongodb中进行增删改查。

　　而通常的mongodb我们一般利用配置文件的形式来设置，这对于后期的交付也特别有利。一般就是以下几个步骤：

　　1.写配置文件mongodb.properties

#mongodb的ip和端口号
ipandport=127.0.0.1:27017
#数据库名字
dbname=mongodbTest

　　2.写得到mongodb的ip和端口号的类及方法GetMongoDBIpAndPort.java

package org.fkit.B2118.util;

import java.io.IOException;
import java.io.InputStream;
import java.util.Properties;

public class GetMongoDBIpAndPort {
        //ip与端口号
	private String ipAndPort;
        //数据库名字
	private String dbname;
        //构造方法
	public void getMongoDBIpAndPort(){

		InputStream inputStream = this.getClass().getClassLoader().getResourceAsStream("mongodb.properties");
				Properties p = new Properties();
				try {
					p.load(inputStream);
					this.ipAndPort = p.getProperty("ipandport");//获取配置文件的值
					this.dbname = p.getProperty("dbname");//获取配置文件的值
				} catch (IOException e) {
					e.printStackTrace();
				}
	}

//setter,getter方法
	public String getIpAndPort() {
		return ipAndPort;
	}
	public void setIpAndPort(String ipAndPort) {
		this.ipAndPort = ipAndPort;
	}
	public String getDbname() {
		return dbname;
	}
	public void setDbname(String dbname) {
		this.dbname = dbname;
	}

}

　　3.写数据库的dao层，对数据库经行操作MongoDb.java

package org.fkit.B2118.dao;

import java.net.UnknownHostException;
import java.util.ArrayList;
import java.util.Date;
import java.util.List;
import org.bson.types.ObjectId;
import org.fkit.B2118.controller.BuyTicketController;
import org.fkit.B2118.domain.B2118ticket;
import org.fkit.B2118.mapper.B2118ticketMapper;
import org.fkit.B2118.service.TicketService;
import org.fkit.B2118.service.TicketServiceImpl;
import org.fkit.B2118.util.GetMongoDBIpAndPort;
import org.springframework.beans.factory.annotation.Autowired;
import org.springframework.beans.factory.annotation.Qualifier;
import org.springframework.stereotype.Controller;
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;
import com.sun.swing.internal.plaf.basic.resources.basic;

public class MongoDb {

	public static Mongo connection = null;
	public static DB database = null;
	public static DBCollection collection;

	public static MongoDb db ;

	@Autowired
	@Qualifier("ticketService")
	public TicketService ticketService;
	public B2118ticketMapper ticketMapper;
	public DBObject dbs = new BasicDBObject();
	/*
	 * 创建一个数据库集合Connection
	 */
	public void createConnection(String name)  throws UnknownHostException, MongoException{
　　　　　　　　　　//利用配置文件及其方法来创建链接
		GetMongoDBIpAndPort getMongoDBIpAndPort= new GetMongoDBIpAndPort();
		getMongoDBIpAndPort.getMongoDBIpAndPort();//构造方法
		String ipandport= getMongoDBIpAndPort.getIpAndPort();//得到ip与port
		String dbname = getMongoDBIpAndPort.getDbname();//得到数据库名字

		//建立一个Mongo的数据库连接对象
		Mongo con = new Mongo(ipandport);
		//创建相关数据库的连接
		DB db = con.getDB(dbname);
		db.createCollection(name, dbs);
	}

　　　　　/*
	 * 打开一个数据库集合Connection
	 */

	public static void openConnection(String name) throws UnknownHostException, MongoException{
		GetMongoDBIpAndPort getMongoDBIpAndPort= new GetMongoDBIpAndPort();
		getMongoDBIpAndPort.getMongoDBIpAndPort();
		String ipandport= getMongoDBIpAndPort.getIpAndPort();
		String dbname = getMongoDBIpAndPort.getDbname();
		System.out.println(ipandport);
		connection = new Mongo(ipandport);
		database = connection.getDB(dbname);
		collection=database.getCollection(name);
	}
	

　　　　　/*
	 * 关闭一个数据库集合Connection
	 */

	public static void closeConnection(String name) {
		connection.close();
	}

	/*
	 * 查询数据
	 */
	public List<B2118ticket> queryTicket() throws UnknownHostException, MongoException {
		//实例化
		try {
			openConnection("ticket");
		} catch (UnknownHostException e) {
			e.printStackTrace();
		} catch (MongoException e) {
			e.printStackTrace();
		}

		List<B2118ticket> b2118ticketlist=new ArrayList<B2118ticket>();
		DBCursor cur = collection.find();
        while (cur.hasNext()) {
        	DBObject object = cur.next();
        	B2118ticket b2118ticket = new B2118ticket();
        		b2118ticket.setTid(String.valueOf(object.get("tid")));
        		b2118ticket.setTrain(String.valueOf(object.get("train")));
        		b2118ticket.setTnum(String.valueOf(object.get("tnum")));
        		b2118ticket.setTtime((Date) object.get("ttime"));
        		b2118ticket.setTtotle(String.valueOf(object.get("ttotle")));
        		b2118ticket.setStart(String.valueOf(object.get("start")));
        		b2118ticket.setStarttime(String.valueOf(object.get("starttime")));
        		b2118ticket.setEnd(String.valueOf(object.get("end")));
        		b2118ticket.setEndtime(String.valueOf(object.get("endtime")));
        		b2118ticket.setPrice(String.valueOf(object.get("price")));
        		b2118ticketlist.add(b2118ticket);
        }
        System.out.println(b2118ticketlist);
        closeConnection("ticket");
        return b2118ticketlist;
	}
	public static int deleteAll(String collName){
		//1.得到集合
		DBCollection coll = database.getCollection(collName);
		DBObject dbs = new BasicDBObject();
		int count = coll.remove(dbs).getN();
		return count;
	}
}