1----Node.js封装mongodb增删改查
2----调用封装好的增删改查

const  MongoClient = require("mongodb"). MongoClient;

const url="mongodb://localhost:27017";
//增 删 改 查
function connect(callback){
    MongoClient.connect(url,(err,db)=>{
        if(err) throw err;
        callback(db)
    })
}
//增
module.exports.insert=(dbname,colname,obj,callback)=>{
    connect((db)=>{
            if(!(obj instanceof Array)){
                obj=[obj]
            }
            db.db(dbname).collection(colname).insertMany(obj,(err,result)=>{
                if(err) throw err;
                console.log("插入数据成功");
                db.close();
               
              callback(result);
            })
    })
}
//删
module.exports.del=(dbname,colname,obj,callback)=>{
    connect((db)=>{
        db.db(dbname).collection(colname).deleteMany(obj,(err,result)=>{
            if(err) throw err;
            console.log("删除");
            db.close();
          callback(result)
        })
    })

}
//改
module.exports.update=(dbname,colname,obj,ob,callback)=>{
    connect((db)=>{
        db.db(dbname).collection(colname).updateMany(obj,{$set:ob},(err,result)=>{
            if(err) throw err;
            console.log("改");
            db.close();
            callback(result);
        })
    })
}

//查
module.exports.find=(dbname,colname,obj,callback)=>{
    connect((db)=>{
        db.db(dbname).collection(colname).find(obj).toArray((err,result)=>{
            if(err) throw err;
            console.log("查询成功");
            callback(result);
        })
    })
}

2----调用封装好的增删改查

const express=require('express');
const app=express();
const dao=require("./feng.js");
//增
app.use('/insert',(req,res)=>{
    dao.insert("teacher","class",[{age:"123",address:"北京"}],(a)=>{
        if(a) res.send("插入成功")
    })
})
//查
app.use("/find",(req,res)=>{
    dao.find("teacher",'class',{age:"123"},(a)=>{
        if(a) res.send(a)
    })
})
//改
app.use("/update",(req,res)=>{
    dao.update("teacher",'class',{age:"123"},{age:"11111"},(a)=>{
        if(a) res.send("修改成功")
    })
})
//删
app.use('/del',(req,res)=>{
    dao.del("teacher","class",{address:"北京"},(a)=>{
        if(a) res.send("删除成功")
    })
})

app.listen('8989')