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Migration.java
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Migration.java
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import java.sql.Connection;
import java.sql.DatabaseMetaData;
import java.sql.DriverManager;
import java.sql.ResultSet;
import java.sql.Statement;
import java.util.HashMap;
import com.mongodb.BasicDBObject;
import com.mongodb.DB;
import com.mongodb.DBCollection;
import com.mongodb.Mongo;
/*
* @author : Sushil jain
* @Email : [email protected]
* @website: http://www.sushiljain.in/
*
**/
public class Migration {
public static void main(String[] args) {
try{
//Load mysql driver
Class.forName("com.mysql.jdbc.Driver");
// Setup the connection with the DB
Connection connect = DriverManager.getConnection("jdbc:mysql://HOST:PORT/DATABASE_NAME?zeroDateTimeBehavior=convertToNull", "username", "password");
//get meta object for database meta info
DatabaseMetaData meta = connect.getMetaData();
// Result set get the result of the SQL query
ResultSet resultSet= meta.getTables(null, null, null, new String[]{"TABLE"});
//Connect to Mongo
Mongo m = new Mongo("localhost", 27017);
//Select database in mongo
DB db = m.getDB("MONGO_DATBASE_NAME");
while(resultSet.next()){
String tableName = resultSet.getString(3);
Statement stmt = connect.createStatement();
ResultSet rs = stmt.executeQuery("show columns from "+tableName);
//Start - Creating mysql query for getting all column names from mysql
HashMap<String,String> fieldsNameArray = new HashMap<String,String>();
StringBuilder query = new StringBuilder("select ");
int totalFields = 0;
while(rs.next())
{
fieldsNameArray.put(rs.getString("Field"), rs.getString("Type"));
query.append("`"+rs.getString("Field")+"`").append(",");
totalFields++;
}
if(totalFields == 0)
continue;
query.deleteCharAt(query.length() -1);
query.append(" from ").append(tableName).append(";");
//End creating MySQL Query
//Now execute query
Statement stmt2 = connect.createStatement();
ResultSet rs2 = stmt2.executeQuery(query.toString());
Object[]obj = fieldsNameArray.keySet().toArray();
DBCollection col = db.getCollection(tableName);
//For every row create mongo entry and inserting it
int i = 0;
while(rs2.next())
{
BasicDBObject mongoObj = new BasicDBObject();
for (int j = 0; j < obj.length; j++)
{
String val = rs2.getString(obj[j].toString());
mongoObj.append(obj[j].toString(), val);
}
col.insert(mongoObj);
i++;
System.out.println("Copying data from table : "+tableName+" -- Row# : "+i);
}
}
//Setting database related objects to null and closing database connections.
rs2 = null;
meta = null;
resultSet = null;
connect.close();
m.close();
}
catch(Exception e)
{
e.printStackTrace();
}
}
}