Java and MongoDB link for project

Given the development of open source projects, embrace the open source community. Discovering Java and MongoDB is a good choice.

As with other databases, Mongo-java-driver is also required to build the interaction between Java and MongoDB.

1. Connect MongoDB

1.1 Connection to a normal database

Mongoclient mongoclient = new Mongoclient ();

Mongoclient mongoclient = new Mongoclient ("localhost");

Mongoclient mongoclient = new Mongoclient ("localhost", 27017);

Mongoclient mongoclient = new Mongoclient (arrays.aslist (New serveraddress ("localhost", 27017), New ServerAddress (" localhost ", 27018), New serveraddress (" localhost ", 27019));

1.2 Database connections with permission requirements

Mongocredential credential = mongocredential.createmongocrcredential (userName, database, password); Mongoclient mongoclient = new Mongoclient (new ServerAddress (), Arrays.aslist (credential));

2. Connect to MongoDB specific database

2.1 Connecting to a specific database

DB db = Mongoclient.getdb ("MyDB");

2.2 Print all databases

List<string> dbs = Mongoclient.getdatabasenames (); for (String Db:dbs) {    System.out.println (db);}

3. Get a specific collection in the database

3.1 Connecting a specific collection

Dbcollection coll = db.getcollection ("testcollection");

3.2 Print all collections

set<string> tables = Db.getcollectionnames (); for (String coll:tables) {    System.out.println (coll);}

4. Inserting Data items

Basicdbobject doc = new Basicdbobject ("name", "MongoDB")        . Append ("type", "Database")        . Append ("Count", 1)        . Append ("Info", New Basicdbobject ("X", 203). Append ("Y", 102)); Coll.insert (DOC);

5. Querying Data items

5.1 Querying the latest data item

DBObject MyDoc = Coll.findone (); System.out.println (MYDOC);

5.2 Querying all data items

dbcursor cursor = Coll.find (); try {while   (Cursor.hasnext ()) {       System.out.println (Cursor.next ())}   } finally {   cursor.close ();}

5.3 Number of data items queried

System.out.println (Coll.getcount ());

5.4 Querying specific data items

5.4.1 equals a condition

Basicdbobject query = new Basicdbobject ("I", +); cursor = coll.find (query); try {while   (Cursor.hasnext ()) {       System.out.println (Cursor.next ());}   } finally {   cursor.close ();}

5.4.2 greater than or less than a certain condition

Find all where i > 50query = new Basicdbobject ("I", New Basicdbobject ("$GT"), cursor = coll.find (query), try {
   while (Cursor.hasnext ()) {        System.out.println (Cursor.next ());}    } finally {    cursor.close ();}

6. Updating data items

Dbcollection table = db.getcollection ("user"); Basicdbobject query = new Basicdbobject (); Query.put ("Name", "Mkyong"); Basicdbobject newdocument = new Basicdbobject () newdocument.put ("name", "mkyong-updated"); Basicdbobject updateobj = new Basicdbobject () updateobj.put ("$set", newdocument); Table.update (query, updateobj);

7. Deleting data items

Dbcollection table = db.getcollection ("user"); Basicdbobject searchQuery = new Basicdbobject () searchquery.put ("name", "Mkyong"); Table.remove (SearchQuery);

Java and MongoDB link for project