mogodb连接测试

–$in

db.Student.find({"_id":{"$in":[1001,1002,1]}})

–$or

db.Student.find({"$or":[{"_id":99},{"pageViews":2}]})

–and and or

db.Student.find({"pageViews":2,"$or":[{"_id":99}]})

游标控制

for(i=0;i<10;i++){
    db.Student.insert({"_id":i});
}

var cursor=db.Student.find();
cursor.forEach(function(x){
    print(x);
});

–分页查询

db.Student.find().limit(3)
db.Student.find().limit(3).skip(3)

–排序

db.Student.find().sort({"_id":-1})      --1为升序，-1为降序
db.Student.find().sort({"_id":-1,"pageView":1})  --前面如果相同就按后面pageView的升序来排序

DBHelper:

package com.yc.link;

import java.net.UnknownHostException;

import com.mongodb.DB;
import com.mongodb.DBCollection;
import com.mongodb.Mongo;
import com.mongodb.MongoException;

public class DBHelper {
        private static Mongo mongo=null;
        private DB db=null;
        static{
            try {
                mongo=new Mongo(Mypro.getInstance().getProperty("ip"),Integer.parseInt(Mypro.getInstance().getProperty("port")));
            } catch (NumberFormatException e) {
                e.printStackTrace();
            } catch (UnknownHostException e) {
                e.printStackTrace();
            } catch (MongoException e) {
                // TODO Auto-generated catch block
                e.printStackTrace();
            }
        }
        public boolean getDB(String dbName,String name,String pwd){
            mongo.getDB(dbName);
            if(name!=null&&!"".equals(name)&&pwd!=null&&!"".equals(pwd)){
                if(db.authenticate(name, pwd.toCharArray())){
                    return true;
                }else{
                    return false;
                }
            }else{//查看配置文件中是否给定用户名和密码
                String uname=Mypro.getInstance().getProperty("uname");
                String pwds=Mypro.getInstance().getProperty("password");
                if(name!=null&&!"".equals(name)&&pwd!=null&&!"".equals(pwd)){
                    if(db.authenticate(name, pwd.toCharArray())){
                    return true;
                }else{
                    return false;
                }
            }
        }
        return true;
}
        /**
         * 关闭链接
         * */
public void closeAll(Mongo mongo){
    if(mongo!=null){
        mongo.close();
    }
}
/**
 * 获取指定的集合
 * collectionName要链接的集合
 * dbName集合所在的数据库
 * 链接数据的用户名
 * 链接数据库的密码
 *
 * */
public DBCollection getDBCollection(String collectionName,String dbName){
    DBCollection dbCollection=null;
    if(getDB(dbName,null,null)){
        db.requestStart();
        if(collectionName==null){//如果为空则冲配置文件中加载
            collectionName=Mypro.getInstance().getProperty(collectionName);
        }
        dbCollection= db.getCollection(collectionName);
    }else{
        throw new RuntimeException("数据库连接失败.....");
    }
    return dbCollection;
}

public DBCollection getDBCollection(String collectionName,String dbName,String name,String password){
    DBCollection dbCollection=null;
    if(getDB(dbName,name,password)){
        db.requestStart();
        if(collectionName==null){//如果为空则冲配置文件中加载
            collectionName=Mypro.getInstance().getProperty(collectionName);
        }
        dbCollection= db.getCollection(collectionName);
    }else{
        throw new RuntimeException("数据库连接失败.....");
    }
    return dbCollection;
}
}

Mypro:单例

package com.yc.link;

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

public class Mypro extends Properties {
        private static Mypro instance=new Mypro();
        private Mypro(){
            InputStream is=Mypro.class.getResourceAsStream("/db.properties");
            try {
                this.load(is);
            } catch (IOException e) {
                e.printStackTrace();
            }finally{
                if(is!=null){
                    try {
                        is.close();
                    } catch (IOException e) {
                        e.printStackTrace();
                    }
                }
            }
        }
        public static Mypro getInstance(){
            return instance;
        }
}

package com.yc.link;

public class Test {
    public static void main(String[] args) {
            DBHelper db=new DBHelper();
            System.out.println(db);
    }

}

db.properties

ip=127.0.0.1

port=27017

dbName=

uname=

password=

collectionName=

DBHelper里应该要多封装一些常用方法，大家可以到网上慢慢收集

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