"MongoDB for Java" Java Operation MongoDB

Development environment:

System:windows

Ide:eclipse, MyEclipse 8

Database:mongodb

Developing dependent libraries:

JavaEE5, Mongo-2.5.3.jar, Junit-4.8.2.jar

Email:[email protected]

Blog:http://blog.csdn.net/ibm_hoojo

http://hoojo.cnblogs.com/

First, the preparatory work

1. First, download MongoDB support for Java driver package

Drive Pack: Https://github.com/mongodb/mongo-java-driver/downloads

MongoDB support for Java, technology: Http://www.mongodb.org/display/DOCS/Java+Language+Center

Drive Source Download: Https://download.github.com/mongodb-mongo-java-driver-r2.6.1-7-g6037357.zip

Online View Source: Https://github.com/mongodb/mongo-java-driver

2. Build a Javaproject project below and import the downloaded driver package. You can use MongoDB in Java with the following directory:

Second, Java operation MongoDB Example

Before this example you need to start the Mongod.exe service, the following program can be executed successfully after startup;

1, establish Simpletest.java, complete the simple MongoDB database operation

Mongo Mongo = new Mongo ();

This creates a MongoDB database connection object, which is connected by default to the current machine's localhost address, and the port is 27017.

DB db = Mongo.getdb ("test");

This will get a test database, if MongoDB does not create this database can also run normally. If you read the previous article, you know that MongoDB can do the data addition without creating the database. When added, without this library, MongoDB will automatically create the current database.

Get the db, next we want to get a "aggregation set dbcollection", through the DB object GetCollection method to complete.

Dbcollection users = db.getcollection ("users");

This gives you a dbcollection, which is equivalent to the "table" of our database.

Querying all data

Dbcursor cur = users.find ();

while (Cur.hasnext ()) {

System.out.println (Cur.next ());

}

Full source

Package com.hoo.test;

Import java.net.UnknownHostException;

Import Com.mongodb.DB;

Import com.mongodb.DBCollection;

Import Com.mongodb.DBCursor;

Import Com.mongodb.Mongo;

Import com.mongodb.MongoException;

Import Com.mongodb.util.JSON;

/**

* <b>function:</b>mongodb Simple Example

* @author Hoojo

* @createDate 2011-5-24 02:42:29

* @file Simpletest.java

* @package Com.hoo.test

* @project MongoDB

* @blog Http://blog.csdn.net/IBM_hoojo

* @email [email protected]

* @version 1.0

*/

public class SimpleTest {

    public static void Main (string[] args) throws Unknownhostexception, Mongoexception {

        Mongo mg = new Mongo ();

        Query all the database

        For (String name:mg.getDatabaseNames ()) {

            System.out.println ("DbName:" + name);

        }

        DB db = Mg.getdb ("test");

        Querying all the aggregation collections

        For (String name:db.getCollectionNames ()) {

            System.out.println ("CollectionName:" + name);

        }

        Dbcollection users = db.getcollection ("users");

        Querying all the data

        Dbcursor cur = users.find ();

        while (Cur.hasnext ()) {

            System.out.println (Cur.next ());

        }

        System.out.println (Cur.count ());

        System.out.println (Cur.getcursorid ());

        System.out.println (json.serialize (cur));

    }

}

2, complete the crud operation, first set up a Mongodb4crudtest.java, the basic test code is as follows:

Package com.hoo.test;

Import java.net.UnknownHostException;

Import java.util.ArrayList;

Import java.util.List;

Import Org.bson.types.ObjectId;

Import Org.junit.After;

Import Org.junit.Before;

Import Org.junit.Test;

Import Com.mongodb.BasicDBObject;

Import com.mongodb.Bytes;

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.mongodb.QueryOperators;

Import Com.mongodb.util.JSON;

/**

* <b>function:</b> to implement MONGODB CRUD operations

* @author Hoojo

* @createDate 2011-6-2 03:21:23

* @file Mongodb4crudtest.java

* @package Com.hoo.test

* @project MongoDB

* @blog Http://blog.csdn.net/IBM_hoojo

* @email [email protected]

* @version 1.0

*/

public class Mongodb4crudtest {

    Private Mongo mg = null;

    private DB DB;

    Private dbcollection users;

    @Before

    public void init () {

        try {

            MG = new Mongo ();

            MG = new Mongo ("localhost", 27017);

        } catch (Unknownhostexception e) {

            E.printstacktrace ();

        } catch (Mongoexception e) {

            E.printstacktrace ();

        }

        Gets the temp DB; if not created by default, MongoDB automatically creates

        db = Mg.getdb ("temp");

        Get users dbcollection; if not created by default, MongoDB will automatically create

        Users = Db.getcollection ("users");

    }

    @After

    public void Destory () {

        if (mg! = null)

            Mg.close ();

        MG = null;

        db = null;

        users = null;

        System.GC ();

    }

    public void print (Object o) {

        System.out.println (o);

    }

}

3. Add operation

Before adding the operation, we need to write a query method to query all the data. The code is as follows:

/**

* <b>function:</b> Search all data

* @author Hoojo

* @createDate 2011-6-2 03:22:40

*/

private void Queryall () {

    Print ("Query all data from users:");

    DB cursors

    Dbcursor cur = users.find ();

    while (Cur.hasnext ()) {

        Print (Cur.next ());

    }

}

@Test

public void Add () {

    Query all data First

    Queryall ();

    Print ("Count:" + users.count ());

    DBObject user = new Basicdbobject ();

    User.put ("name", "Hoojo");

    User.put ("Age", 24);

    Users.save (user) Save, GETN () Gets the number of rows affected

    Print (Users.save (user). GETN ());

    Expand Fields, add fields as you wish, without affecting existing data

    User.put ("Sex", "male");

    Print (Users.save (user). GETN ());

    Add multiple data, pass array object

    Print (Users.insert (user, new Basicdbobject ("name", "Tom")). GETN ());

    Add List Collection

    list<dbobject> list = new arraylist<dbobject> ();

    List.add (user);

    DBObject user2 = new Basicdbobject ("name", "Lucy");

    User.put ("Age", 22);

    List.add (User2);

    Add List Collection

    Print (Users.insert (list). GETN ());

    Query the data to see if the add succeeds

    Print ("Count:" + users.count ());

    Queryall ();

}

4. Delete data

@Test

public void Remove () {

    Queryall ();

    Print ("Delete id = 4de73f7acd812d61b4626a77:" + users.remove (New Basicdbobject ("_id", New ObjectId (" 4de73f7acd812d61b4626a77 ")). GETN ());

    Print ("Remove Age >=:" + users.remove (New Basicdbobject (' age ', New Basicdbobject ("$gte")). GETN ());

}

5. Modify the data

@Test

public void Modify () {

    Print ("Modify:" + users.update (New Basicdbobject ("_id", New ObjectId ("4dde25d06be7c53ffbd70906")), New Basicdbobject ("Age ). GETN ());

    Print ("Modify:" + users.update (

            New Basicdbobject ("age", 121),

            true,//If the database does not exist, whether to add

            false//Multiple Modifications

            ). GETN ());

    Print ("Modify:" + users.update (

            New Basicdbobject ("name", "Dingding"),

            true,//If the database does not exist, whether to add

            True//false only change the first day, true if there are more than one, do not modify

            ). GETN ());

    Do not modify or add data when the database does not exist, when multiple data is not modified

    Print ("Modify multiple:" + coll.updatemulti (New Basicdbobject ("_id", New ObjectId ("4dde23616be7c19df07db42c"), new Basicdbobject ("Name", "199"));

}

6. Query data

@Test

public void query () {

    Query all

    Queryall ();

    Query id = 4de73f7acd812d61b4626a77

    Print ("Find id = 4de73f7acd812d61b4626a77:" + users.find (New Basicdbobject ("_id", New ObjectId (" 4de73f7acd812d61b4626a77 ")). ToArray ());

    Query age = 24

    Print ("Find age =:" + users.find (New Basicdbobject ("Age",)). ToArray ());

    Query Age >= 24

    Print ("Find age >=:" + users.find (New Basicdbobject ("Age", New Basicdbobject ("$gte")). ToArray ());

    Print ("Find age <=:" + users.find (New Basicdbobject ("Age", New Basicdbobject ("$lte")). ToArray ());

    Print ("Query age!=25:" + users.find (New Basicdbobject ("Age", New Basicdbobject ("$ne")). ToArray ());

    Print ("Query age in 25/26/27:" + users.find (New Basicdbobject ("Age", New Basicdbobject (queryoperators.in, new int[] {25, 26, )). ToArray ());

    Print ("Query age not in 25/26/27:" + users.find (New Basicdbobject ("Age", New Basicdbobject (Queryoperators.nin, new int[] {25, )). ToArray ());

    Print ("Query Age exists sort:" + users.find (New Basicdbobject ("Age", New Basicdbobject (Queryoperators.exists, True)). ToArray ());

    Print ("Query only Age Property:" + Users.find (null, New Basicdbobject ("Age", true)). ToArray ());

    Print ("Check properties only:" + users.find (null, New Basicdbobject ("Age", true), 0, 2). ToArray ());

    Print ("Check properties only:" + users.find (null, New Basicdbobject ("Age", true), 0, 2, bytes.queryoption_notimeout). ToArray ());

    Query only one piece of data, multiple to the first

    Print ("FindOne:" + users.findone ());

    Print ("FindOne:" + users.findone (New Basicdbobject ("Age", 26));

    Print ("FindOne:" + users.findone (New Basicdbobject ("Age", "page"), New Basicdbobject ("name", true));

    Query modification, deletion

    Print ("Findandremove query age=25 data, and delete:" + users.findandremove (New Basicdbobject ("Age", 25));

    Query the age=26 data, and modify the value of name to ABC

    Print ("findandmodify:" + users.findandmodify ("New Basicdbobject" ("Age", "page"), New Basicdbobject ("name", "ABC"));

    Print ("findandmodify:" + users.findandmodify (

        New Basicdbobject ("Age", 28),//Querying age=28 data

        New Basicdbobject ("name", true),//Query the Name property

        New Basicdbobject ("Age", true),//Sort by age

        False,//Whether Delete, true means delete

        New Basicdbobject ("name", "ABC"),//modified value, change name to ABC

        true));

    Queryall ();

}

MongoDB does not support federated queries, subqueries, which need to be done by ourselves in the program. The result set of the query is filtered in the Java query as needed.

7. Other operations

public void Testothers () {

    DBObject user = new Basicdbobject ();

    User.put ("name", "Hoojo");

    User.put ("Age", 24);

    JSON Object Transformation        

    Print ("Serialize:" + json.serialize (user));

    Deserialization

    Print ("Parse:" + json.parse ("{\" name\ ": \" hoojo\ ", \" age\ ": 24}"));

    Print ("Determine if temp collection exists:" + db.collectionexists ("temp"));

    If it does not exist, create

    if (!db.collectionexists ("temp")) {

        DBObject options = new Basicdbobject ();

        Options.put ("size", 20);

        Options.put ("capped", 20);

        Options.put ("Max", 20);

        Print (Db.createcollection ("Account", options));

    }

    Set DB to read-only

    Db.setreadonly (TRUE);

    Read-only cannot write data

    Db.getcollection ("Test"). Save (user);

}

"MongoDB for Java" Java Operation MongoDB