MongoDB Learning (2) Add, query, modify, and delete MongoDBJava

Related information 1. MongoDBforJava driver package github. commongodbmongo-java-driverdownloads2, online documentation www. mongodb. orgdisplayDOCSJava + Language + Center operation 1. query all data in a table (called a set in MongoDB) using the Java code DBTest. javapack

Related information 1, MongoDB for Java driver package https://github.com/mongodb/mongo-java-driver/downloads 2, online document http://www.mongodb.org/display/DOCS/Java+Language+Center operations 1, query a table (called set in MongoDB) All data Java code DBTest. java pack

Related Materials

1. MongoDB for Java driver package

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

2. Online Documentation

Http://www.mongodb.org/display/DOCS/Java+Language+Center

Operation

1. query all data in a table (called a set in MongoDB ).

Java code DBTest. java

Package com. archie. mongodb;

Import java.net. UnknownHostException;

Import com. mongodb. DB;
Import com. mongodb. DBCollection;
Import com. mongodb. DBCursor;
Import com. mongodb. DBObject;
Import com. mongodb. Mongo;
Import com. mongodb. parse exception;

/**

* Query all data in the specified DBCollection set of the specified database
* @ Author archie2010
*
* Since 10:40:21
*/
Public class DBTest {
Public static void main (String [] args) throws UnknownHostException,
Except exception {
/**
The Mongo instance represents a database connection pool.
* Mongo mg = new Mongo ("localhost ");
Mongo mg = new Mongo ("localhost", 27017 );
*/
Mongo mg = new Mongo ();

// Obtain the database object named "dbtest"
DB db = mg. getDB ("dbtest ");
// Query all sets in the database (equivalent to tables)
For (String name: db. getCollectionNames ()){
System. out. println ("Collection Name:" + name );
}
DBCollection users = db. getCollection ("emp ");
// Query all data in the Set
DBCursor cur = users. find ();
System. out. println ("Record Count:" + cur. count ());
While (cur. hasNext ()){
DBObject object = cur. next ();
System. out. println (object );
// Retrieve the data with the Field Names 'uname' and 'upwd 'in the object list.
System. out. println ("uname:" + object. get ("uname") + "\ tupwd :"
+ Object. get ("upwd "));
}
}
}

Running result:

2. CRUD operation on the specified DBCollection set

Java code

DBUtil. java

Package com. archie. mongodb;

Import java.net. UnknownHostException;

Import com. mongodb. DB;
Import com. mongodb. DBCollection;
Import com. mongodb. Mongo;

/**
* Get the tool class of the DBCollection set
* @ Author archie2010
*
* Since 10:54:42
*/
Public class DBUtil {

Public static Mongo mg = null;
Public static DB db = null;
Public static DBCollection collection;

/**
* Get the DBCollection object
* @ Param dbName
* @ Param colName
* @ Return
*/
Public static DBCollection getDBCollection (String dbName, String colName ){
If (mg = null ){
Try {
Mg = new Mongo ();
} Catch (UnknownHostException e ){
E. printStackTrace ();
}
}
If (db = null ){
Db = mg. getDB (dbName );
}
Return db. getCollection (colName );
}
}

CRUDTest. java

Package com. archie. mongodb;

Import com. mongodb. BasicDBObject;
Import com. mongodb. DBCollection;
Import com. mongodb. DBCursor;
Import com. mongodb. DBObject;

/**

* CRUD operation on the specified DBCollection set
* @ Author archie2010
*
* Since 10:51:24
*/
Public class CRUDTest {
/**
* Added
* @ Param obj
*/
Public static void add (DBObject obj ){
DBCollection coll = DBUtil. getDBCollection ("dbtest", "emp ");
Coll. insert (obj );
}
/**
* Delete
* @ Param obj
*/
Public static void delete (DBObject obj ){
DBCollection coll = DBUtil. getDBCollection ("dbtest", "emp ");
Coll. remove (obj );
}
/**
* Query
*/
Public static void query (){
DBCollection coll = DBUtil. getDBCollection ("dbtest", "emp ");
// Query all data in the Set
DBCursor cur = coll. find ();
System. out. println ("Record Count:" + cur. count ());
While (cur. hasNext ()){
DBObject object = cur. next ();
System. out. println (object );
// Retrieve data whose list is 'uname' and 'upwd'
System. out. println ("uname:" + object. get ("uname") + "\ tupwd :"
+ Object. get ("upwd") + "\ t_id:" + object. get ("_ id "));
}
}
/**
* Modify
*/
Public static void modify (DBObject orig, DBObject update ){
DBCollection coll = DBUtil. getDBCollection ("dbtest", "emp ");
Coll. update (orig, update, true, false );
}
Public static void main (String [] args ){
DBObject empObj = new BasicDBObject ();
EmpObj. put ("uname", "teddy ");
EmpObj. put ("upwd", "123456 ");
// Add
Add (empObj );
Query ();

DBObject updateObj = new BasicDBObject ();
UpdateObj. put ("uname", "teddy ");
UpdateObj. put ("upwd", "3333 ");
// Update
Modify (new BasicDBObject ("uname", "teddy"), updateObj );
System. out. println ("----------------------- after modification -------------------");
Query ();

// Delete
Delete (new BasicDBObject ("uname", "teddy "));
System. out. println ("----------------------- after deletion -------------------");
Query ();
}
}

Running effect:

Sample download