Data Access Object is the import component of the design patter of java. It provides a technique to separating the object persistence and data access logic. All the basic data access code contains in DAO and it provides a simple interface to access the data.
In DAO you need to create the Connection factory class. This class contains the code for getting connection to the database.
For Example-
public class ConnectionFactory { String driverName = "com.mysql.jdbc.Driver"; String conUrl = "jdbc:mysql://192.168.10.13:3306/onlinexamination"; String dbUser = "root"; String dbPwd = "root"; private static ConnectionFactory connectionFactory = null; private ConnectionFactory() { try { Class.forName(driverName); } catch (ClassNotFoundException e) { e.printStackTrace(); } } public Connection getConnection() { Connection conn = null; try { conn = DriverManager.getConnection(conUrl, dbUser, dbPwd); } catch (Exception e) { e.toString(); } return conn; } public static ConnectionFactory getInstance() { if (connectionFactory == null) { connectionFactory = new ConnectionFactory(); } return connectionFactory; } }
Then Write the operatios on the on the table in a seperate classADS_TO_REPLACE_1 AS
package net.roseindia.DAO; import java.sql.Connection; import java.sql.PreparedStatement; import java.sql.ResultSet; import java.sql.SQLException; import java.util.ArrayList; import java.util.Iterator; import net.roseindia.model.FinalResultModel; import net.roseindia.model.PaperResultModel; public class FinalResultDAO { Connection connect; PreparedStatement pst; ResultSet rs; int rightAns = 0, wrongAns = 0; int counter = 0, i = 0; public Connection getConnection() { Connection con; con = ConnectionFactory.getInstance().getConnection(); return con; } public void selectedAns(PaperResultModel obPaperSubmitModel, String language) { connect = getConnection(); String ansQuesQuery = "insert into result_info(username,quesno,selectopt,language) values(?,?,?,?)"; try { pst = connect.prepareStatement(ansQuesQuery); pst.setString(1, obPaperSubmitModel.getUsername()); pst.setString(2, obPaperSubmitModel.getQuesno()); pst.setString(3, obPaperSubmitModel.getAnswer()); pst.setString(4, obPaperSubmitModel.getLanguage()); pst.execute(); System.out.println("Paper Successfully inserted in database."); } catch (SQLException e) { e.printStackTrace(); } finally { try { if (rs != null) { rs.close(); } if (pst != null) { pst.close(); } } catch (Exception e) { e.toString(); } } } }
QuestionDAO obQuestionDAO = new QuestionDAO(); int i = obQuestionDAO.addQuestion(obQuestionModel);
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