Introduction to MongoDB for Java, PHP and Python Developers

jieforest · 发表于 2012-6-6 08:35

Figure 8: Adding Mongo jar file to your project

Once you have it all setup, working with Java and MongoDB is quite easy as shown in figure 9.

jieforest · 发表于 2012-6-6 08:36

Figure 9 Using MongoDB from Eclipse

The above is roughly equivalent to the console/JavaScript code that we were doing earlier. The BasicDBObject is a type of Map with some convenience methods added. The DBCursor is like a JDBC ResultSet. You execute queries with DBColleciton.

There is no query syntax, just finder methods on the collection object. The output from the above is:

Out:
{ "_id" : { "$oid" : "4f964d3000b5874e7a163895"} , "name" : "Rick
Hightower" , "gender" : "m" , "phone" : "520-555-1212" ,
"age" : 42.0}
{ "_id" : { "$oid" : "4f984cce72320612f8f432bb"} , "name" : "Diana
Hightower" , "gender" : "f" , "phone" : "520-555-1212" ,
"age" : 30}

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jieforest · 发表于 2012-6-6 08:37

Once you create some documents, querying for them is quite simple as show in figure 10.

Figure 10: Using Java to query MongoDB

The output from figure 10 is as follows:

Rick?
{ "_id" : { "$oid" : "4f964d3000b5874e7a163895"} , "name" : "Rick
Hightower" , "gender" : "m" , "phone" : "520-555-1212" ,
"age" : 42.0}
Diana?
{ "_id" : { "$oid" : "4f984cae72329d0ecd8716c8"} , "name" : "Diana
Hightower" , "gender" : "f" , "phone" : "520-555-1212" ,
"age" : 30}
Diana by object id?
{ "_id" : { "$oid" : "4f984cce72320612f8f432bb"} , "name" : "Diana
Hightower" , "gender" : "f" , "phone" : "520-555-1212" ,
"age" : 30}

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jieforest · 发表于 2012-6-7 04:24

Just in case anybody wants to cut and paste any of the above, here it is again all in one go in the following listing.

Listing: Complete Java Listing

package com.mammatustech.mongo.tutorial;
import org.bson.types.ObjectId;
import com.mongodb.BasicDBObject;
import com.mongodb.DBCollection;
import com.mongodb.DBCursor;
import com.mongodb.DBObject;
import com.mongodb.Mongo;
import com.mongodb.DB;
public class Mongo1Main {
public static void main (String [] args) throws Exception {
Mongo mongo = new Mongo();
DB db = mongo.getDB("tutorial");
DBCollection employees = db.getCollection("employees");
employees.insert(new BasicDBObject().append("name", "Diana Hightower")
.append("gender", "f").append("phone", "520-555-1212").append("age", 30));
DBCursor cursor = employees.find();
while (cursor.hasNext()) {
DBObject object = cursor.next();
System.out.println(object);
}
//> db.employees.find({name:"Rick Hightower"})
cursor=employees.find(new BasicDBObject().append("name", "Rick Hightower"));
System.out.printf("Rick?\n%s\n", cursor.next());
//> db.employees.find({age:{$lt:35}})
BasicDBObject query = new BasicDBObject();
query.put("age", new BasicDBObject("$lt", 35));
cursor=employees.find(query);
System.out.printf("Diana?\n%s\n", cursor.next());
//> db.employees.findOne({_id : ObjectId("4f984cce72320612f8f432bb")})
DBObject dbObject = employees.findOne(new BasicDBObject().append("_id",
new ObjectId("4f984cce72320612f8f432bb")));
System.out.printf("Diana by object id?\n%s\n", dbObject);
}
}

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Please note that the above is completely missing any error checking, or resource cleanup. You will need do some of course (try/catch/finally, close connection, you know that sort of thing).

jieforest · 发表于 2012-6-7 04:26

Python MongoDB Setup

Setting up Python and MongoDB are quite easy since Python has its own package manager.

To install mongodb lib for Python MAC OSX, you would do the following:

$ sudo env ARCHFLAGS='-arch i386 -arch x86_64'
$ python -m easy_install pymongo

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To install Python MongoDB on Linux or Windows do the following:

$ easy_install pymongo

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or

$ pip install pymongo

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If you don't have easy_install on your Linux box you may have to do some sudo apt-get install python-setuptools or sudo yum install python-setuptools iterations, although it seems to be usually installed with most Linux distributions these days.

If easy_install or pip is not installed on Windows, try reformatting your hard disk and installing a real OS, or if that is too inconvient go here.

jieforest · 发表于 2012-6-7 04:44

Once you have it all setup, you will can create some code that is equivalent to the first console examples as shown in figure 11.

Figure 11: Python code listing part 1

import pymongo
from bson.objectid import ObjectId
connection = pymongo.Connection()
db = connection["tutorial"]
employees = db["employees"]
employees.insert({"name":"Lucas Hightower",'gender':'m','phone':'520-555-1212','age':8})
cursor = db.employees.find()
for employee in db.employees.find()
print employee

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Python does have literals for maps so working with Python is much closer to the JavaScript/Console from earlier than Java is. Like Java there are libraries for Python that work with MongoDB (MongoEngine, MongoKit, and more).

Even executing queries is very close to the JavaScript experience as shown in figure 12.

Figure 12: Python code listing part 2

print employees.find({"name":"Rick Hightower"})[0]
# Output
# {u'gender':u'm',u'age':42.0,u'_id':ObjectId('4f964d3000b5874e7a163895'),
# u'name':u'Rick Hightower',u'phone':u'520-555-1212'}
cursor = employees.find({"age":{"$lt":35}})
for employee in cursor:
print "under 35: %s" % employee
# Output
#under 35: {u'gender':u'f',u'age': 30, u'_id':ObjectId("4f985a7f72323465ed25cccd'),u'name':
#u'Diana Hightower', u'phone':u'520-555-1212'}
#under 35:{u'gender':u'm',u'age':8,u'_id':ObjectId('4f9e111980cbd54eea000000'),u'name':
#u'Lucas Hightower', u'phone':u'520-555-1212'}
diana = employees.find_one({"_id":ObjectId("4f984cce72320612f8f432bb")})
print "Diana %s" % diana
#Output
#Diana {u'gender': u'f', u'age':30, u'_id':ObjectId('4f984cce72320612f8f432bb'),
#u'name': u'Diana Hightower', u'phone': u'520-555-1212'}

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jieforest · 发表于 2012-6-7 04:45

Here is the complete listing to make the cut and paste crowd (like me), happy.

Listing: Complete Python listing

import pymongo
from bson.objectid import ObjectId
connection = pymongo.Connection()
db = connection["tutorial"]
employees = db["employees"]
employees.insert({"name": "Lucas Hightower", 'gender':'m', 'phone':'520-555-1212', 'age':8})
cursor = db.employees.find()
for employee in db.employees.find():
print employee
print employees.find({"name":"Rick Hightower"})[0]
cursor = employees.find({"age": {"$lt": 35}})
for employee in cursor:
print "under 35: %s" % employee
diana = employees.find_one({"_id":ObjectId("4f984cce72320612f8f432bb")})
print "Diana %s" % diana

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The output for the Python example is as follows:

{u'gender': u'm', u'age': 42.0, u'_id': ObjectId('4f964d3000b5874e7a163895'), u'name': u'Rick Hightower', u'phone':
u'520-555-1212'}
{u'gender': u'f', u'age': 30, u'_id': ObjectId('4f984cae72329d0ecd8716c8'), u'name': u'Diana Hightower', u'phone':
u'520-555-1212'}
{u'gender': u'm', u'age': 8, u'_id': ObjectId('4f9e111980cbd54eea000000'), u'name': u'Lucas Hightower', u'phone':
u'520-555-1212'}

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jieforest · 发表于 2012-6-7 04:46

All of the above but in PHP

Node.js , Ruby, and Python in that order are the trend setter crowd in our industry circa 2012. Java is the corporate crowd, and PHP is the workhorse of the Internet. The "get it done" crowd. You can't have a decent NoSQL solution without having good PHP support.

To install MongoDB support with PHP use pecl as follows:

$ sudo pecl install mongo

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Add the mongo.so module to php.ini.

extension=mongo.so

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Then assuming you are running it on apache, restart as follows:

$ apachectl stop
$ apachectl start

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jieforest · 发表于 2012-6-8 06:12

Figure 13 shows our roughly equivalent code listing in PHP.

Figure 13 PHP code listing

The output for figure 13 is as follows:

Output:
array ( '_id' => MongoId::__set_state(array( '$id' => '4f964d3000b5874e7a163895', )), 'name' => 'Rick Hightower',
'gender' => 'm', 'phone' => '520-555-1212', 'age' => 42, )
array ( '_id' => MongoId::__set_state(array( '$id' => '4f984cae72329d0ecd8716c8', )), 'name' => 'Diana Hightower', 'gender' => ‘f',
'phone' => '520-555-1212', 'age' => 30, )
array ( '_id' => MongoId::__set_state(array( '$id' => '4f9e170580cbd54f27000000', )), 'gender' => 'm', 'age' => 8, 'name' => 'Lucas Hightower',
'phone' => '520-555-1212', )

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jieforest · 发表于 2012-6-8 06:13

The other half of the equation is in figure 14.

Figure 14 PHP code listing

The output for figure 14 is as follows:

Output
Rick?
array ( '_id' => MongoId..., 'name' => 'Rick Hightower', 'gender' => 'm',
'phone' => '520-555-1212', 'age' => 42, )
Diana?
array ( '_id' => MongoId::..., 'name' => 'Diana Hightower', 'gender' => ‘f',
'phone' => '520-555-1212', 'age' => 30, )
Diana by id?
array ( '_id' => MongoId::..., 'name' => 'Diana Hightower', 'gender' => 'f',
'phone' => '520-555-1212', 'age' => 30, )

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