Note Java Web

prj321.md

This is document prepare for practice example course Web-Based Java Applications. DBContext

package com.context;
import java.sql.Connection;
import java.sql.DriverManager;

public class DBContext {
    /*USE BELOW METHOD FOR YOUR DATABASE CONNECTION FOR BOTH SINGLE AND MULTILPE SQL SERVER INSTANCE(s)*/
    /*DO NOT EDIT THE BELOW METHOD, YOU MUST USE ONLY THIS ONE FOR YOUR DATABASE CONNECTION*/
     public Connection getConnection()throws Exception {
        String url = "jdbc:sqlserver://"+serverName+":"+portNumber +";databaseName="+dbName;
        Class.forName("com.microsoft.sqlserver.jdbc.SQLServerDriver");
        return DriverManager.getConnection(url, userID, password);
    }
    /*Insert your other code right after this comment*/
    /*Change/update information of your database connection, DO NOT change name of instance variables in this class*/
    private final String serverName = "localhost"; //127.0.0.1
    private final String dbName = "......";
    private final String portNumber = "1433";
    private final String userID = "sa";
    private final String password = "123456";
}

Insert

public void .........(String ........., in.........) {
    Connection con = null;
    DBContext db = new DBContext();
    try {
        con = db.getConnection();
        String sql = "INSERT INTO ........(......) VALUES (?, ?)";
        PreparedStatement stmt con.prepareStatement(sql);
        stmt.setString(1, .........);
        stmt.setInt(2, .........);
        stmt.executeUpdate();
        stmt.close();
        con.close();
    } catch (Exception ex) {
        ex.printStackTrace();
    }
}

Select

public int .........(String .........) {
    Connection con = null;
    DBContext db = new DBContext();
    try {
        con = db.getConnection();
        Statement stmt = con.createStatement();
        String sql = "SELECT ......... FRO......... WHERE ........ ='........";
        ResultSet rs = stmt.executeQuery(sql);
        while (rs.next()) {
            int ........ = rs.getInt(1);
            return studentId;
        }
        rs.close();
        stmt.close();
        con.close();
    } catch (Exception ex) {
        ex.printStackTrace();
    }
    return -1;
}

Update

public void .........(String ........., in.........) {
    Connection con = null;
    DBContext db = new DBContext();
    try {
        con = db.getConnection();
        String sql = "UPDATE ......... SE......... = ? WHERE ......... = ?";
        PreparedStatement stmt con.prepareStatement(sql);
        stmt.setString(1, .........);
        stmt.setInt(2, .........);
        stmt.executeUpdate();
        stmt.close();
        con.close();
    } catch (Exception ex) {
        ex.printStackTrace();
    }
}

Delete

public void .........(String id) {
    Connection con = null;
    DBContext db = new DBContext();
    try {
        con = db.getConnection();
        String sql = "DELETE FROM ........WHERE ......... = ?";
        PreparedStatement stmt con.prepareStatement(sql);
        stmt.setString(1, id);
        stmt.executeUpdate();
        stmt.close();
        con.close();
    } catch (Exception ex) {
        ex.printStackTrace();
    }
    return;
}

Wellcome file

<welcome-file-list>
  <welcome-file>index.html</welcome-file>
</welcome-file-list>