Simple CRUD operations with Java and MongoDB — Part 1

This post is about how to do basic CRUD operations using java and MongoDB.

There are 4 ways to insert document to MongoDB using java.

• BasicDBObject
• BasicDBObjectBuilder
• Map (Using java HashMap)
• Simple JSON string

Suppose here is the data we need to insert.

{
 "database" : "technodyne",
 "table" : "MyCollection",
 "detail" : 
  {
   records : 99,
   index : "vps_index1",
   active : "true"
  }
 }
}

Here is how to perform data insertion in four different ways.

[sourcecode language=”java”]

package com.technodyne.core;

import java.net.UnknownHostException;
import java.util.HashMap;
import java.util.Map;

import com.mongodb.BasicDBObject;
import com.mongodb.BasicDBObjectBuilder;
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.util.JSON;

public class InsertDocumentApp {

public void insertDocument(){

try {

Mongo mongo = new Mongo(“127.0.0.1”,27017);
DB db = mongo.getDB(“technodyne”);

DBCollection collection = db.getCollection(“MyCollection”);

[/sourcecode]

Using BasicDBObject

[sourcecode language=”java”]

// BasicDBObject example
System.out.println(“BasicDBObject example…”);
BasicDBObject document = new BasicDBObject();
document.put(“database”, “technodyne”);
document.put(“table”, “MyCollection”);

BasicDBObject documentDetail = new BasicDBObject();
documentDetail.put(“records”, “99”);
documentDetail.put(“index”, “vps_index1”);
documentDetail.put(“active”, “true”);

document.put(“detail”,documentDetail);

collection.insert(document);

DBCursor cursor = collection.find();
while(cursor.hasNext()){
System.out.println(cursor.next());
}
collection.remove(new BasicDBObject());

[/sourcecode]

Using BasicDBObjectBuilder

[sourcecode language=”java”]

// BasicDBObjectBuilder example
System.out.println(“BasicDBObjectBuilder example…”);
BasicDBObjectBuilder documentBuilder = BasicDBObjectBuilder.start().
add(“database”, “technodyne”)
.add(“table”, “MyCollection”);
BasicDBObjectBuilder documentBuilderDetail = BasicDBObjectBuilder.start()
.add(“records”, “99”)
.add(“index”,”vps_index1")
.add(“active”,”true”);
documentBuilder.add(“detail”,documentBuilderDetail.get());

collection.insert(documentBuilder.get());

DBCursor cursorDocBuilder = collection.find();
while(cursorDocBuilder.hasNext()){
System.out.println(cursorDocBuilder.next());
}
collection.remove(new BasicDBObject());

[/sourcecode]

Using hashMap

[sourcecode language=”java”]

// Map example
System.out.println(“Map example…”);
Map documentMap = new HashMap();
documentMap.put(“database”, “technodyne”);
documentMap.put(“table”, “MyCollection”);

Map documentMapDetail = new HashMap();
documentMapDetail.put(“records”, “99”);
documentMapDetail.put(“index”,”vps_index1");
documentMapDetail.put(“active”, “true”);

documentMap.put(“detail”,documentMapDetail);

collection.insert(new BasicDBObject(documentMap));

DBCursor cursorDocMap = collection.find();
while(cursorDocMap.hasNext()){
System.out.println(cursorDocMap.next());
}

collection.remove(new BasicDBObject());

[/sourcecode]

Finally json Object

[sourcecode language=”java”]

// JSON parse example
System.out.println(“JSON parse example…”);
String json =”{‘database’:’technodyne’,’table’:’MyCollection’,”+
“‘detail’:{‘records’:99,’index’:’vps_index1',’active’:’true’}}”;

DBObject dbObject = (DBObject) JSON.parse(json);
collection.insert(dbObject);

DBCursor cursorDocJSON = collection.find();
while (cursorDocJSON.hasNext()) {
System.out.println(cursorDocJSON.next());

}
} catch (UnknownHostException e) {
// TODO: handle exception
e.printStackTrace();
}

catch (MongoException e) {
// TODO: handle exception
e.printStackTrace();
}
}
}
[/sourcecode]

Then run this method

[sourcecode language=”java”]
InsertDocumentApp insertApp = new InsertDocumentApp();
insertApp.insertDocument();
[/sourcecode]

This is the result