Java crud for MongoDB

Driver package download: https://github.com/mongodb/mongo-java-driver/downloads
I downloaded mongo-2.8.0.jar-
Version 2.8.0
Open Mongo shell -- create database test -- (use test)
Open eclipse new project, import JUnit, mongo-2.8.0.jar.
The new test class is as follows:

Package COM. DB; import java.net. unknownhostexception; import Java. util. arraylist; import Java. util. list; import Org. bson. types. objectid; import Org. JUnit. after; import Org. JUnit. test; 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. except exception; public class dbutils {Private Static Mongo; Private Static dB; static {try {Mongo = new Mongo ("localhost", 27017);} catch (unknownhostexception e) {e. printstacktrace ();} catch (except exception e) {e. printstacktrace ();} dB = Mongo. getdb ("test") ;}@ after public void output () {// after the test, all dbcollection DBS = dB is displayed. getcollection ("user"); dbcursor cursor = DBC. find (); While (cursor. hasnext () {// cursor. next is One line of record (one document) system. out. println (cursor. next () ;}@ test public void testinsert () throws exception {dbcollection DBC = dB. getcollection ("user"); dbobject object = new basicdbobject (); object. put ("username", "zdw"); object. put ("password", "123"); // a person has a position // database JSON format: {Username: "zdw", password: "123", position: {name: "engineer"} basicdbobject o = new basicdbobject (); O. put ("name", "manager"); object. put ("POS Ition ", O); DBC. insert (object); object = new basicdbobject (); object. put ("username", "zhangjun"); object. put ("password", "456"); // one person has multiple positions (one document contains multiple documents) // database JSON format: {Username: "zhangjun ", password: "456", position: [{name: "engineer" },{ name: "designer"}]} List <Object> List = new arraylist <Object> (); O = new basicdbobject (); O. put ("name", "engineer"); list. add (o); O = new basicdbobject (); O. put ("name", "designer"); list. add (O); object. put ("position", list); DBC. insert (object) ;}// Delete the specified @ test public void testremoveone () throws exception {dbcollection DBC = dB. getcollection ("user"); dbobject o = new basicdbobject (); O. put ("username", "zhangjun"); DBC. remove (o) ;}@ test public void testmodify () throws exception {dbcollection DBC = dB. getcollection ("user"); // you need to add $ set to change the password Based on the ID. Otherwise, the password of all records will be modified and other fields will be deleted. Int result = DBC. update (New basicdbobject ("_ id", new objectid ("4ff8eaa65dbc67340278a07c"), new basicdbobject ("$ set", new basicdbobject ("password ", "4444 "))). getn (); system. out. println (result) ;}@ test public void testremove () throws exception {dbcollection DBC = dB. getcollection ("user"); // Delete All dbrs. drop () ;}// query specified @ test public void testfindone () throws exception {dbcollection DBC = dB. getcollection ("user"); dbobject o = new basicdbobject (); O. put ("username", "zdw"); dbobject OBJ = DBC. findone (o); system. out. println (OBJ );}}

This key-value storage method facilitates operations.
Source code download