Spring Hibernate sample application

Spring Hibernate Integration Login Example using MySQL database and Tomcat Web Server.

A short description of how Spring MVC works (source : http://www.javacodegeeks.com)

When a request is sent to the Spring MVC Framework the following sequence of events happen.

• The “DispatcherServlet” first receives the request
• The “DispatcherServlet” consults the “HandlerMapping” and invokes the "Controller" associated with the request
• The "Controller" process the request by calling the appropriate service methods and returns a “ModeAndView” object to the “DispatcherServlet”. The “ModeAndView” object contains the model data and the view name
• The “DispatcherServlet” sends the view name to a “ViewResolver” to find the actual “View” to invoke
• The “DispatcherServlet” passes the model object to the “View” to render the result
• The “View” with the help of the model data renders the result and return it back to the user 

Eg : Employee Login:

Java Spring sample application

Spring tutorial example

The Spring Framework consists of features organized into about 20 modules. These modules are grouped into Core Container, Data Access/Integration, Web, AOP (Aspect Oriented Programming),Instrumentation, and Test.

-The Core Container consists of the Core, Beans, Context, and Expression Language modules.

-The Data Access/Integration layer consists of the JDBC, ORM, OXM, JMS and Transaction modules.

-The Web layer consists of the Web, Web-Servlet, Web-Struts, and Web-Portlet modules.

-Spring's AOP module provides an AOP Alliance-compliant aspect-oriented programming.

-The Test module supports the testing of Spring components with JUnit or TestNG.

A simple example in spring (3.x)

************************

MySQL data Encryption and Decryption using AES_ENCRYPT and AES_DECRYPT

Encryption and Decryption using AES_ENCRYPT and AES_DECRYPT

First create a table called test_encdec :

mysql> create table test_encdec(

 -> name varchar(30),

 -> password varbinary(150)

 -> );

Query OK, 0 rows affected (0.14 sec)

mysql> desc test_encdec;

+----------+----------------+------+-----+---------+-------+

| Field | Type | Null | Key | Default | Extra |

+----------+----------------+------+-----+---------+-------+

| name | varchar(30) | YES | | NULL | |

| password | varbinary(150) | YES | | NULL | |

+----------+----------------+------+-----+---------+-------+

2 rows in set (0.00 sec)

 mysql> insert into  test_encdec values('S L N V Praveen',aes_encrypt('praveen','
myname'));
Query OK, 1 row affected (0.01 sec)

mysql> select * from  test_encdec;
+-----------------+------------------+
| name            | password         |
+-----------------+------------------+
| S L N V Praveen | 8#sTyn ]7?û¬+W¬2 |
+-----------------+------------------+
1 row in set (0.02 sec)

mysql> select name,aes_decrypt(password,'myname') from  test_encdec;
+-----------------+--------------------------------+
| name            | aes_decrypt(password,'myname')     |
+-----------------+--------------------------------+
| S L N V Praveen | praveen                                   |
+-----------------+--------------------------------+
1 row in set (0.00 sec)

mysql> select aes_decrypt(password,'myname') from  test_encdec;
+--------------------------------+
| aes_decrypt(password,'myname') |
+--------------------------------+
| praveen                        |
+--------------------------------+
1 row in set (0.00 sec)

Finding first/last day of the previous month using Calendar class in Java

Calendar is an abstract base class and implements Serializable and Cloneable interfaces.

Calendar provides 'getInstance' class method, returns Calendar object whose time fields have been initialized with the current date and time.
Calendar presentTime = Calendar.getInstance();

To find the last day/first day of the month

import java.text.SimpleDateFormat;
import java.util.Calendar;
import java.util.Date;
public class FindHistDate{ public static void getLastMonthLastDate() { 

 SimpleDateFormat sdf = new SimpleDateFormat("dd-MMM-yyyy"); 
 Calendar calendar = Calendar.getInstance();
 calendar.add(Calendar.MONTH, -1); 
 int max = calendar.getActualMaximum(Calendar.DAY_OF_MONTH);
 calendar.set(Calendar.DAY_OF_MONTH, max);
 Date pme = calendar.getTime();
 System.out.println(sdf.format(pme));

 int min = calendar.getActualMinimum(Calendar.DAY_OF_MONTH);
 calendar.set(Calendar.DAY_OF_MONTH, min);
 Date pms = calendar.getTime();
 System.out.println(pms);
}
 public static void main(String[] args) {
 FindHistDate.getLastMonthLastDate();
 }
}

o/p:

29-Feb-2012
Wed Feb 01 11:24:27 IST 2012

Convert Date to String and String to Date in Java

It's most obvious scenario where you need to convert Date to String and vice versa.

Example : Date to String

import java.text.DateFormat;
import java.text.SimpleDateFormat;
import java.util.Date;

public class DateToString { 
 public static void main(String[] args) {  
  Date d = new Date();
  DateFormat df = new SimpleDateFormat("dd-MMM-yyyy");
  String str_dt = df.format(d);
  System.out.println("Date : "+str_dt);
 }
}

o/p :

Date : 27-Feb-2012

Example : String to Date

import java.text.ParseException;
import java.text.SimpleDateFormat;
import java.util.Date;

public class StringToDate {
 public static void main(String[] args) throws ParseException {
  String d = "27-Jan-2012";
  SimpleDateFormat sdf = new SimpleDateFormat("dd-MMM-yyyy");
  Date date = sdf.parse(d);
  System.out.println("Date : "+date);  
 }
}

o/p :
Date : Fri Jan 27 00:00:00 IST 2012

JSF(Java Server Faces) tutorial sample application

Java Server Faces(JSF) is a specification which defines a Component based MVC framework.

Typically,

Model       - Managed Beans

View         - Components

Controller  - FacesServlet

Building high quality web application user interfaces is hard as it involves HTTP request/response model,browser capabilities,need to support multiple client device types.

JSF to the rescue: