TechnicalToday

Spring Framework - MethodReplacer Example in spring

2013-03-27T01:48:00.002-07:00

Spring framework with AOP show many magic.One of them is Method Replacer .In this activity the called method is replaced by another method. To understand clearly have a good example-
Directory Structure-

Class Ract.java-

package com.test;

public class Ract {

String name;

public String getName() {
return name;
}

public void setName(String name) {
this.name = name;
}

public String getContent()
{
return "hello methd";
}

}

class Triangle.java-

package com.test;

public class Triangle {

private String type;
private int height;
private Ract ract;

public Ract getRact() {
return ract;
}

public void setRact(Ract ract) {
this.ract = ract;
}

public int getHeight() {
return height;
}

public void setHeight(int height) {
this.height = height;
}
public String getContent()
{
return "pre method";
}

public String getType() {
return type;
}
public void setType(String type) {
this.type = type;
}
public void draw()
{
System.out.println( getType()+"Triangle.\n The height is="+getHeight() );
System.out.println("ractangle is="+ract.getName());
System.out.println("getcontent method="+getContent());
}

}

Class MethodReplace.java-

package com.test;

import java.lang.reflect.Method;

import org.springframework.beans.factory.support.MethodReplacer;

public class MethodReplace implements MethodReplacer {

@Override
public Object reimplement(Object arg0, Method arg1, Object[] arg2)
throws Throwable {
// TODO Auto-generated method stub
return "huree!!!!I m Replaced";
}

}

class DrawApp.java-

package com.test;

import org.springframework.context.support.AbstractApplicationContext;
import org.springframework.context.support.ClassPathXmlApplicationContext;

public class DrawApp {

public static void main(String a[])
{
AbstractApplicationContext context=new ClassPathXmlApplicationContext("spring.xml");
context.registerShutdownHook();//callsdestroy method dow the rsorce
Triangle tri= (Triangle) context.getBean("triangle");
tri.draw();
}
}

spring.xml -

<?xml version="1.0" encoding="UTF-8"?>

<!DOCTYPE beans PUBLIC "-//SPRING//DTD BEAN 2.0//EN" "http://www.springframework.org/dtd/spring-beans-2.0.dtd">

<beans>
<bean id="ract" class="com.test.Ract">
<property name="name" value="navin's"></property>
</bean>
<bean id="mrp" class="com.test.MethodReplace"></bean>

<bean id="triangle" class="com.test.Triangle">
<property name="type" value="test"></property>
<property name="height" value="2"></property>
<property name="ract" ref="ract"></property>
<replaced-method name="getContent" replacer="mrp" />
</bean>

</beans>

Output-

testTriangle.
The height is=2
ractangle is=navin's
getcontent method=huree!!!!I m Replaced

Spring Framework - Example of Database Connectivity with DataSource

2013-03-26T22:09:00.000-07:00

After lot of basic tutorials and topics now we start database connectivity .In spring framework DataSource in used to define the database configuration.In XML configuration file use DriverManagerDataSource class is used to set the database configuration like driver,pool,username and password.so understand clearly here below is a simple example-

Directory Structure-

class Student.java-

package com.test.student;

public class Student {
int id;
String name;
public int getId() {
return id;
}
public Student(int id, String name) {
super();
setId(id);
setName(name);
}
public void setId(int id) {
this.id = id;
}
public String getName() {
return name;
}
public void setName(String name) {
this.name = name;
}
}

Class DaoImpl.java

package com.test.daoimp;

import java.sql.Connection;
/*import java.sql.DriverManager;*/
import java.sql.PreparedStatement;
import java.sql.ResultSet;

import javax.annotation.PostConstruct;
import javax.annotation.PreDestroy;
import javax.sql.DataSource;

import org.springframework.beans.factory.annotation.Autowired;
import org.springframework.stereotype.Component;

import com.test.student.Student;
@Component
public class DaoImpl {
Student stu=null;
private DataSource dataSource;
public DataSource getDataSource() {
return dataSource;
}
@Autowired
public void setDataSource(DataSource dataSource) {
this.dataSource = dataSource;
}
public Student getStu(int id)
{
try {

Connection con=dataSource.getConnection();

PreparedStatement st=con.prepareStatement("select * from stu where id=?");

st.setInt(1, id);
ResultSet rs=st.executeQuery();
if( rs.next())
{
stu=new Student(id,rs.getString("name"));
}

con.close();
st.close();
rs.close();

} catch (Exception e) {
// TODO Auto-generated catch block
e.printStackTrace();
}
return stu;

}
@PostConstruct
public void initialmethod()
{
System.out.println("Welcome to database");
}

@PreDestroy
public void destroymethod()
{
System.out.println("!!!!!!!!!!!GooD Bye!!!!!!!!");
}

}

@PostConstruct annotation used method call after the constructor is initialized and @Predestroy annotate method is calls when the scope or datasoure object scope is finished ,to call the predestory need to call the method registerShutdownHook by the AbstractApplicationContext object which is define as in main.java class.

Class Main.java-

package com.test.Dao;

/*import java.io.DataInputStream;*/
import org.springframework.context.support.AbstractApplicationContext;
import org.springframework.context.support.ClassPathXmlApplicationContext;

import com.test.daoimp.DaoImpl;

public class Main {

public static void main(String args[])
{

AbstractApplicationContext ctx=new ClassPathXmlApplicationContext("spring.xml");
ctx.registerShutdownHook();
DaoImpl di=ctx.getBean("daoImpl",DaoImpl.class);
System.out.println("Student name is="+di.getStu(1).getName());

}

}

spring.xml-

<?xml version="1.0" encoding="UTF-8"?>
<beans xmlns="http://www.springframework.org/schema/beans"
xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
xmlns:aop="http://www.springframework.org/schema/aop"
xsi:schemaLocation="http://www.springframework.org/schema/aop http://www.springframework.org/schema/aop/spring-aop.xsd
http://www.springframework.org/schema/beans http://www.springframework.org/schema/beans/spring-beans.xsd
http://www.springframework.org/schema/context http://www.springframework.org/schema/context/spring-context.xsd"
xmlns:context="http://www.springframework.org/schema/context">

<context:annotation-config></context:annotation-config>

<context:component-scan base-package="com.test"></context:component-scan>

<bean id="dataSource" class="org.springframework.jdbc.datasource.DriverManagerDataSource">
<property name="driverClassName" value="com.mysql.jdbc.Driver"></property>
<property name="url" value="jdbc:mysql://localhost:3306/Student"></property>
<property name="username" value="root"></property>
<property name="password" value="root"></property>

</bean>
</beans>

Output-

Welcome to database
Student name is=navin
!!!!!!!!!!!GooD Bye!!!!!!!!

Spring Framework- Execption handling in AOP

2013-03-25T11:18:00.001-07:00

Hureeeee!!!!! Today in spring framework we learn some intresting with AOP, so today topic is Execption handling. AOP contain a method proceed() . If this method is proceed with exception then it pass the controll of the program to the catch block, In That type examples we can also used @AfterThrowing , @AfterReturning ,@Around . here we use @Around annotation to follow the AOP. So here below is the example --

Class circle.java-

package com.test.App;

public class Circle {

String name;

public String getName() {

return name;

}

public void setName(String name) {

this.name = name;

}

Class Triangle.java-

package com.test.App;

public class Triangle {
String name;

public String getName() {
return name;
}

public void setName(String name) {
this.name = name;
}

}

Class Shape.java-

package com.test.service;

import com.test.App.Circle;
import com.test.App.Triangle;

public class Shape {

Circle circle;
Triangle triangle;
public Circle getCircle() {
throw (new RuntimeException());
}
public void setCircle(Circle circle) {
this.circle = circle;
}
public Triangle getTriangle() {
return triangle;
}
public void setTriangle(Triangle triangle) {
this.triangle = triangle;
}

}

Class LogAspect.java-

package com.test.aspect;

import org.aspectj.lang.JoinPoint;
import org.aspectj.lang.ProceedingJoinPoint;
import org.aspectj.lang.annotation.AfterReturning;
import org.aspectj.lang.annotation.AfterThrowing;
import org.aspectj.lang.annotation.Around;
import org.aspectj.lang.annotation.Aspect;
import org.aspectj.lang.annotation.Before;
import org.aspectj.lang.annotation.Pointcut;

@Aspect
public class LogAspect {

@Before("allcircle()")
public void loggingAdvice(JoinPoint joinpoint)
{
System.out.println("advice");
}

@Pointcut("execution(* get*())")
public void allGetters()
{
System.out.println("Wel Come With....allgetters");

}

@Pointcut("within(com.test.App.Circle)")
public void allcircle()
{
System.out.println("Wel Come With....circle");

}

@AfterReturning(pointcut="args(name)",returning="returnstring")
public void strigArgs(String name,Object returnstring)
{
System.out.println("string args is used"+name+"return string is="+returnstring);
}
@AfterThrowing(pointcut="args(name)",throwing="ex")
public void throwEX(String name,RuntimeException ex)
{
System.out.println("exception is call "+ex);

}
@Around("allGetters()")
public Object aroundProcess(ProceedingJoinPoint process)
{
try {
System.out.println("before advice");
process.proceed();
System.out.println("atfer advice");
} catch (Throwable e) {
// TODO Auto-generated catch block
System.out.println("After throw");

}
System.out.println("After finally");

return null;
}
}

Class Main.java

package com.test.aop;

import org.springframework.context.ApplicationContext;
import org.springframework.context.support.ClassPathXmlApplicationContext;

import com.test.service.Shape;

public class Main {

public static void main(String[] args) {

ApplicationContext context=new ClassPathXmlApplicationContext("spring.xml");
Shape sh=context.getBean("shape", Shape.class);
sh.getCircle();
}

}

Spring.xml-

<?xml version="1.0" encoding="UTF-8"?>
<beans xmlns="http://www.springframework.org/schema/beans"
xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
xmlns:aop="http://www.springframework.org/schema/aop"
xsi:schemaLocation="http://www.springframework.org/schema/aop http://www.springframework.org/schema/aop/spring-aop.xsd
http://www.springframework.org/schema/beans http://www.springframework.org/schema/beans/spring-beans.xsd
http://www.springframework.org/schema/context http://www.springframework.org/schema/context/spring-context.xsd"
xmlns:context="http://www.springframework.org/schema/context">

<aop:aspectj-autoproxy/>
<bean id="triangle" class="com.test.App.Triangle">
<property name="name" value="triangle drawn"></property>
</bean>
<bean id="circle" class="com.test.App.Circle">
<property name="name" value="circle drawn"></property>
</bean>
<bean id="shape" class="com.test.service.Shape" autowire="byName">
</bean>
<bean id="log" class="com.test.aspect.LogAspect"></bean>
</beans>

Output-

before advice
After throw
After finally

Spring Framework - Example to use @Before annotation with args() in AOP

2013-03-25T10:56:00.001-07:00

Here In AOP, we discuss that how use @Before(args()).Here args() is contain the name of arguments with pass to the function and also can use that argument.Now see a example to understand that-

Class circle.java-

package com.test.App;

public class Circle {

String name;

public String getName() {

return name;

}

public void setName(String name) {

this.name = name;

}

Class Triangle.java-

package com.test.App;

public class Triangle {
String name;

public String getName() {
return name;
}

public void setName(String name) {
this.name = name;
}

}

Class Shape.java-

package com.test.service;

import com.test.App.Circle;
import com.test.App.Triangle;

public class Shape {

Circle circle;
Triangle triangle;
public Circle getCircle() {
return circle;
}
public void setCircle(Circle circle) {
this.circle = circle;
}
public Triangle getTriangle() {
return triangle;
}
public void setTriangle(Triangle triangle) {
this.triangle = triangle;
}

}

Class LogAspect.java-

package com.test.aspect;

import org.aspectj.lang.JoinPoint;
import org.aspectj.lang.annotation.Aspect;
import org.aspectj.lang.annotation.Before;
import org.aspectj.lang.annotation.Pointcut;

@Aspect
public class LogAspect {

@Before("allGetters() && allcircle()")
public void loggingAdvice(JoinPoint joinpoint)
{
System.out.println("joinpoint calls");
System.out.println(joinpoint.toString());
System.out.println(joinpoint.getTarget());

}

@Pointcut("execution(* get*())")
public void allGetters()
{
System.out.println("Wel Come With....allgetters");

}

@Pointcut("within(com.test.App.Circle)")
public void allcircle()
{
System.out.println("Wel Come With....circle");

}

@Before("args(name)")
public void strigArgs(String name)
{
System.out.println("string args is used"+name);
}
}

Here is necessary that String(name) and args (name) . Both underline parameter name is same.

Class Main.java

Spring.xml-

triangle drawn
string args is usednavin's
joinpoint calls
execution(String com.test.App.Circle.getName())
com.test.App.Circle@b1074a
navin's

Here define that how can use pointcuts ans joinpoint also,and how we can access the argument using annotations.

Spring Framework-Example to use JoinPoint in AOP

2013-03-18T11:25:00.001-07:00

Hello Friends, After discussing the pointcuts in last post Now discuss on Joinpoint . A Joinpoint is a point in the execution of the application where an aspect can be plugged in. this point could be a method being called Here is a example to understands the use of pointcuts-

Circle.java-

package com.test.App;

public class Circle {

String name;

public String getName() {

return name;

}

public void setName(String name) {

this.name = name;

}

Triangle.java

package com.test.App;

public class Triangle {

String name;

public String getName() {

return name;

}

public void setName(String name) {

this.name = name;

}

LogAspect.java

package com.test.aspect;

import org.aspectj.lang.JoinPoint;

//import org.aspectj.lang.annotation.After;

import org.aspectj.lang.annotation.Aspect;

import org.aspectj.lang.annotation.Before;

import org.aspectj.lang.annotation.Pointcut;

@Aspect

public class LogAspect {

@Before("allGetters()")

public void loggingAd(JoinPoint jp)

{

System.out.println(jp.toString());

}

@Before("allcircle()")

public void loggingAdvice(JoinPoint jp)

{

System.out.println(jp.toString());

}

@Pointcut("execution(* get*())")

public void allGetters()

{

System.out.println("Wel Come With....allgetters");

}

@Pointcut("within(com.test.App.Circle)")

public void allcircle()

{

System.out.println("Wel Come With....circle");

}

Shape.java

package com.test.service;

import com.test.App.Circle;

import com.test.App.Triangle;

public class Shape {

Circle circle;

Triangle triangle;

public Circle getCircle() {

return circle;

}

public void setCircle(Circle circle) {

this.circle = circle;

}

public Triangle getTriangle() {

return triangle;

}

public void setTriangle(Triangle triangle) {

this.triangle = triangle;

}

Main.java-

package com.test.aop;

import org.springframework.context.ApplicationContext;

import org.springframework.context.support.ClassPathXmlApplicationContext;

import com.test.service.Shape;

public class Main {

public static void main(String[] args) {

ApplicationContext context=new ClassPathXmlApplicationContext("spring.xml");

Shape sh=context.getBean("shape", Shape.class);

System.out.println(sh.getTriangle().getName());

System.out.println(sh.getCircle().getName());

}

Spring.xml

<?xml version="1.0" encoding="UTF-8"?>

<beans xmlns="http://www.springframework.org/schema/beans"

xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"

xmlns:aop="http://www.springframework.org/schema/aop"

xsi:schemaLocation="http://www.springframework.org/schema/aop http://www.springframework.org/schema/aop/spring-aop.xsd

http://www.springframework.org/schema/beans http://www.springframework.org/schema/beans/spring-beans.xsd

http://www.springframework.org/schema/context http://www.springframework.org/schema/context/spring-context.xsd"

xmlns:context="http://www.springframework.org/schema/context">

<aop:aspectj-autoproxy/>

</bean>

</bean>

</bean>

</beans>

Output

execution(Triangle com.test.service.Shape.getTriangle())
execution(String com.test.App.Triangle.getName())
triangle drawn
execution(Circle com.test.service.Shape.getCircle())
execution(String com.test.App.Circle.getName())
execution(String com.test.App.Circle.getName())
circle drawn

JoinPoint class contain the information related to the object which pass by pointcut.

Spring Framework- Example to Use Pointcuts in AOP

2013-03-17T12:43:00.000-07:00

In Aspect Oriented Programming (AOP) Advice define the what and when we call . The Pointcuts define where.A pointcut definition matches one or more jointpoints .Here discuss a simple example to use pointcut -

Directory Structure-

Circle Class-

package com.test.App;

public class Circle {
String name;

public String getName() {
return name;
}

public void setName(String name) {
this.name = name;
}

}

Triangle Class-

package com.test.App;

public class Triangle {
String name;

public String getName() {
return name;
}

public void setName(String name) {
this.name = name;
}

}

Class shape-

Class LogAspect-

package com.test.aspect;

//import org.aspectj.lang.annotation.After;
import org.aspectj.lang.annotation.Aspect;
import org.aspectj.lang.annotation.Before;
import org.aspectj.lang.annotation.Pointcut;

@Aspect
public class LogAspect {

@Before("allGetters() && allcircle()")
public void loggingAdvice()
{
System.out.println("Wel Come With....logging advice");
}

@Pointcut("execution(* get*())")
public void allGetters()
{
System.out.println("Wel Come With....allgetters");

}

@Pointcut("within(com.test.App.Circle)")
public void allcircle()
{
System.out.println("Wel Come With....circle");

}
}

Class Main-

Spring.XML

<?xml version="1.0" encoding="UTF-8"?>
<beans xmlns="http://www.springframework.org/schema/beans"
xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
xmlns:aop="http://www.springframework.org/schema/aop"
xsi:schemaLocation="http://www.springframework.org/schema/aop http://www.springframework.org/schema/aop/spring-aop.xsd
http://www.springframework.org/schema/beans http://www.springframework.org/schema/beans/spring-beans.xsd
http://www.springframework.org/schema/context http://www.springframework.org/schema/context/spring-context.xsd"
xmlns:context="http://www.springframework.org/schema/context">

<aop:aspectj-autoproxy/>
<bean id="triangle" class="com.test.App.Triangle">
<property name="name" value="triangle drawn"></property>
</bean>
<bean id="circle" class="com.test.App.Circle">
<property name="name" value="circle drawn"></property>
</bean>
<bean id="shape" class="com.test.service.Shape" autowire="byName">
</bean>
<bean id="log" class="com.test.aspect.LogAspect"></bean>
</beans>

Output

triangle drawn
Wel Come With....logging advice
circle drawn

Here logginAdvice() combind all type of getter and setter method and call the function.Method allCircle() call when Circle class's methods calls.so all other methods indirectly pass to logginAdvice().

Spring Framework- Simple Aspect Oriented Programming Example

2013-03-16T13:17:00.002-07:00

Aspect Oriented Programming basically provide alternative way to achive the inheritance and the delegation.In AOP define the comman fuctionality in one place,but you can define where and how this functionlity is applied. The basic example of the aspect oriented programming is describe here-

Directory Structure-

Circle.java-

package com.test.App;
public class Circle
{
String name;
public String getName()
{ return name; }
public void setName(String name)
{ this.name = name; }
}

Triangle.java-

package com.test.App;
public class Triangle
{
String name;
public String getName()
{ return name; }
public void setName(String name)
{ this.name = name; }
}

LogAspect.java

package com.test.aspect;
import org.aspectj.lang.annotation.Before;
import org.aspectj.lang.annotation.Aspect;

@Aspect
public class LogAspect {
@Before("execution(public String getName())")
public void loggingAdvice()
{
System.out.println("Wel Come With....");
}
}

Shape.java

package com.test.service;
import com.test.App.Circle;
import com.test.App.Triangle;
public class Shape
{
Circle circle;
Triangle triangle;
public Circle getCircle()
{ return circle; }
public void setCircle(Circle circle)
{ this.circle = circle; }
public Triangle getTriangle()
{ return triangle; }
public void setTriangle(Triangle triangle)
{ this.triangle = triangle; }
}

Main.java

package com.test.aop;
import org.springframework.context.ApplicationContext;
import org.springframework.context.support.ClassPathXmlApplicationContext;
import com.test.service.Shape;

public class Main
{
public static void main(String[] args)
{
ApplicationContext context=new ClassPathXmlApplicationContext("spring.xml");
Shape sh=context.getBean("shape", Shape.class);
System.out.println(sh.getTriangle().getName());
System.out.println(sh.getCircle().getName());
}
}

spring.xml

<beans xmlns:aop="http://www.springframework.org/schema/aop" xmlns:context="http://www.springframework.org/schema/context" xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance" xmlns="http://www.springframework.org/schema/beans" xsi:schemalocation="http://www.springframework.org/schema/aop http://www.springframework.org/schema/aop/spring-aop.xsd
http://www.springframework.org/schema/beans http://www.springframework.org/schema/beans/spring-beans.xsd
http://www.springframework.org/schema/context http://www.springframework.org/schema/context/spring-context.xsd">

<aop:aspectj-autoproxy>
<bean class="com.test.App.Triangle" id="triangle">
<property name="name" value="triangle drawn"></property>
</bean>
<bean class="com.test.App.Circle" id="circle">
<property name="name" value="circle drawn"></property>
</bean>
<bean autowire="byName" class="com.test.service.Shape" id="shape">
</bean>
<bean class="com.test.aspect.LogAspect" id="log"></bean>
</aop:aspectj-autoproxy></beans>

In this example LogAspect is advice class which contain the jointpoint method-loggingAdvice().This method execute Before all method which contain the prototype -public String getName().the code <aop:aspectj-autoproxy/> which written in xml create proxy(or aop objects).
The process of AOP is also called Weaving.The LogAspect class is also called Advice Class.

Output

Wel Come With....
triangle drawn
Wel Come With....
circle drawn

JSP Tutorials

2012-11-06T04:32:00.001-08:00

Lets learn JSP step by step with easy tutorials and examples. To get all tutorials click on below link-

Click to get JSP tutorials.

How to jsp is process in web application ?

2012-11-06T03:03:00.004-08:00

Here we discuss how a jsp page is processed in web application when it is requested by the users-

1. First time JSP page is loaded by the JSP container which is also called jsp engine(Where the JSPs complied) .Here the Jsp generated and complied java code which is called servlet code . This code is loaded in servlet engine. This process is occurs on translation time . It is important to note that this occurs only the first time when jsp is requested.

By this process there will be slow response time for first page.
2. When the page is modified, is automatically reloaded and recompiled by the container when the page request is occurs. This process is occurs on run time.

There are three major life event methods -
jspInit().
jspService(request,response).
jspDestroy().

In most cases the jspInit() and jspDestroy() methods don't need to be provide developer.

What are the differences between jsp and servlet ?

2012-11-06T02:39:00.000-08:00

Both techniques are used to handle the web request in java or creating dynamic content with web pages-

Servlets- servlets executed on server and acting as a middle layer between clients and lower level applications.servlets contain the html code in java program. servlets are well suited to deciding how to handle client requests and invoke them but are not well suited for generating contents.Here markup code is harder to implement or maintain in web application. Developers need more experience of java to written servlets.

JSP- Jsp designed and developed less like programs and more like web pages.Generating html is much easier than servlets. Java code is written in html program or in html code.Jsp can use java bean with specified scope(Session,Request).

What is JSP ?

2012-11-06T02:25:00.001-08:00

JSP stands for java server pages. JSP is server sided language which execute only server .The goal of the JSP specification is , creation and management of dynamic web pages. it provide more convenient way than servlets.JSP pages combine static markup like HTML,XML with scripting tags. The main thing is that each server page is translated into servlet the first time invoked.

Version of JSP 1.0 released in September 1999 and JSP 1.2 released in December 1999.

XML parsing in java

2012-11-05T03:23:00.002-08:00

XML is a good thing to cntaint database and other information. Java use parsers to read and write the xml data so here we learn how we can use xml in our java application.Here provided step by step tutorials with example to understand the functionality of XML with java.

Lets click here to learn XML and XML parsing in java.

What is XML ?

2012-11-04T22:12:00.001-08:00

Markup language that define a set of rules for encoding documents in a form that is both human-readable and machine-readable.
• It is defined in the XML 1.0 Specification produced by the W3C, and several other related specifications.
• Can be embedded with all types of oop language with parsing.
Benefits-
1. Simple
2. Self description
3. Contains machine readable context information
4. Facilitates the aggregation of data
5. Can embed multiple datatypes and existing data.

How to insert a record in table using hibernate.

2012-11-04T21:22:00.001-08:00

Hibernate is a ORM.To insert the record in table basically a object is inserted which contain the all attribute of that record field. for insertion create a bean class of that types variable and apply getter and setter property.now initialize a object of that class inject the values and save the object after it the table is updated and record is inserted.

To see the code click here.

How to write hibernate code in java application

2012-11-03T23:07:00.000-07:00

To use hibernate first setup the environment of hibernate .After that need to create some files in application as-

1. Hibernate.cfg.xml file contain database configuration,connection pool,user,username,password and other sql information. the main thing is that we can not change file name the name always as it is.

<hibernate-configuration>
<session-factory>
<property name="hibernate.connection.driver_class">
com.mysql.jdbc.Driver</property>
<property name="hibernate.connection.url">
jdbc:mysql://localhost:3306/hibern</property>
<property name="hibernate.connection.username">root</property>
<property name="hibernate.connection.password">root</property>
<property name="hibernate.connection.pool_size">10</property>
<property name="show_sql">true</property>
<property name="dialect">org.hibernate.dialect.MySQLDialect</property>
<property name="hibernate.hbm2ddl.auto">update</property>

<mapping resource="createtable.hbm.xml">
</mapping></session-factory>
</hibernate-configuration>

Here property <property name="hibernate.connection.driver_class"> is use to load the driver of particular database and <mapping resource="createtable.hbm.xml"/> property define the mapping file which contain the mapping with database table.

2.Mapping file (Create.hbm.xml) file contain the mapping of the table as-

<hibernate-mapping>
<class name="com.test.CreateTable" table="CONTACT">
<id column="ID" name="id" type="long">
<generator class="increment">
</generator></id>

<property name="firstName">
<column name="FIRSTNAME">
</column></property>
<property name="lastName">
<column name="LASTNAME">
</column></property>
<property name="email">
<column name="EMAIL">
</column></property>
</class>
</hibernate-mapping>

Here class name define the java file which contain the bean file who have id,firstname,lastname,email variables with getter and setter properties and these properties is mapped with database table here no need to create database table when code is execute automatically create a table with that fields.

3. bean file is use to inject the object values-

package com.test;

import java.io.Serializable;

public class CreateTable implements Serializable{
private String firstName;
private String lastName;
private String email;
private long id;
public String getFirstName() {
return firstName;
}
public void setFirstName(String firstName) {
this.firstName = firstName;
}
public String getLastName() {
return lastName;
}
public void setLastName(String lastName) {
this.lastName = lastName;
}
public String getEmail() {
return email;
}
public void setEmail(String email) {
this.email = email;
}
public long getId() {
return id;
}
public void setId(long id) {
this.id = id;
}
}

4. Main Class to do the transaction with the database -

package com.test;

import org.hibernate.Session;
import org.hibernate.SessionFactory;
import org.hibernate.cfg.Configuration;
public class Main {
public static void main(String[] args) throws Exception{
Session session = null;
SessionFactory sessionfactory;
sessionfactory = new Configuration().configure("hibernate.cfg.xml").buildSessionFactory();
session =sessionfactory.openSession();
//Create new instance of CreateTable and set
session.beginTransaction();
System.out.println("Inserting Record");
CreateTable createTable = new CreateTable();
createTable.setFirstName("navin");
createTable.setLastName("bansal");
createTable.setEmail("nav@gmail.com");
session.save(createTable);
session.getTransaction().commit();
System.out.println("Done");
session.flush();
session.close();
}
}

now execute this file and a record is automatically inserted is your database table.
Output-

Inserting Record
Hibernate: select max(ID) from CONTACT
Hibernate: insert into CONTACT (FIRSTNAME, LASTNAME, EMAIL, ID) values (?, ?, ?, ?)
Done

yupee!!!!!!!!! the code is executed.now see the table-

How to set Hibernate environment in java application

2012-11-03T22:09:00.000-07:00

To provide the ORM in java application need to implement the hibernate. To implement the hibernate need the jars or libraries which is provided by hibernate download these jar and add these jar in application and use the benefits of hibernate.

To download the Hibernate jars click on below link-

http://sourceforge.net/projects/hibernate/files/hibernate3/3.6.10.Final/hibernate-distribution-3.6.10.Final-dist.tar.gz/download

After download that library. add these jars in project. now application is ready to use hibernate.

What is Hibernate ?

2012-11-02T09:14:00.002-07:00

Hibernate is an object-relational mapping (ORM) library for the Java language, providing a framework for mapping an object-oriented domain model to a traditional relational database. Hibernate solves object-relational impedance mismatch problems by replacing direct persistence-related database accesses with high-level object handling functions.

Hibernate is free software that is distributed under the GNU Lesser General Public License. Hibernate's primary feature is mapping from Java classes to database tables (and from Java data types to SQL data types). Hibernate also provides data query and retrieval facilities. It also generates the SQL calls and attempts to relieve the developer from manual result set handling and object conversion and keep the application portable to all supported SQL databases with little performance overhead

Mapping Java classes to database tables is accomplished through the configuration of an XML file or by using Java Annotations. When using an XML file, Hibernate can generate skeletal source code for the persistence classes. This is unnecessary when annotations are used. Hibernate can use the XML file or the annotations to maintain the database schema. Facilities to arrange one-to-many and many-to-many relationships between classes are provided. In addition to managing associations between objects, Hibernate can also manage reflexive associations where an object has a one-to-many relationship with other instances of its own type.

Hibernate supports the mapping of custom value types. This makes the following scenarios possible:

1. Overriding the default SQL type that Hibernate chooses when mapping a column to a property.

2. Mapping Java bean to columns as if they were regular properties.

3. Mapping a single property to multiple columns.

Hibernate provides an SQL inspired language called Hibernate Query Language (HQL) which allows SQL-like queries to be written against Hibernate's data objects. Criteria Queries are provided as an object-oriented alternative to HQL .Hibernate can be used both in standalone Java applications and in Java EE applications using servlets, EJB session beans, and JBI service components. It can also be included as a feature in other programming languages.

Hibernate was started in 2001 by Gavin King as an alternative to using EJB2-style entity beans. Its mission back then was to simply offer better persistence capabilities than offered by EJB2 by simplifying the complexities and allowing for missing features.

Early in 2003, the Hibernate development team began Hibernate2 releases which offered many significant improvements over the first release. JBoss, Inc. (now part of Red Hat) later hired the lead Hibernate developers and worked with them in supporting Hibernate.

In 2010, Hibernate version 3.x was released with the features like: a new Interceptor/Callback architecture, user defined filters, and JDK 5.0 Annotations (Java's metadata feature). As of 2010 Hibernate 3 (version 3.5.0 and up) was a certified implementation of the Java Persistence API 2.0 specification via a wrapper for the Core module which provides conformity with the JSR 317 standard.

In Dec 2011, Hibernate Core 4.0.0 Final was released. This includes new features like: Initial multi-tenancy support, Introduction of ServiceRegistry (which is a major change in how Hibernate builds and manages "services"), Clean up of Session opening from SessionFactory, Improved integration via org.hibernate.integrator.spi.Integrator and auto discovery, Improved logging with i18n support and message codes, Initial work on more clear split between API, SPI and implementation classes, Clean up of deprecated methods, classes.

Hibernate Tutorials

2012-07-26T10:31:00.000-07:00

Lets learn Hibernate with fun. Here provide step by step tutorials to learn Core Hibernate or Hibernate+Spring ,with simple and easily understandable example .

visit to see contains of Hibernate-http://www.technicaltoday.com/p/hibernate.html

What is ORM ?

2012-07-26T09:46:00.001-07:00

ORM stands for Object Relation Mapping.The term Object Relation Mapping refers the technique to map the data from an object model representation to a relation data model.ORM provide the mapping for java classes with hibernate and it also provides data query and retrieval facilities.It remove the overhead of manually data handling in SQL and JDBC.

Now days Hibernate which is provided for java classes use that technique.

Spring Framework Tutorials

2012-06-25T11:49:00.001-07:00

Lets learn spring framework with fun. Here provide step by step tutorials to learn spring framework,with simple and easily understandable example .
visit to see contain of spring framework -http://www.technicaltoday.com/p/spring.html

BeanNameAware and ApplicationContextAware in spring

2012-06-24T22:15:00.000-07:00

Spring offer awareness with beans and Applicationcontext.
BeanNameAware interface provide to know bean information like name aware(know who you are).
ApplicationContextAware interface provide to know context information like context aware(Know where you live).
public setBeanName(String bean);
this method contain the name of the bean which is implement the interface BeanNameAware
public void setApplicationContext(ApplicationContext context)
this contain the container of context information where that bean exist.necessary to implement that class with ApplicationContextAware interface.
let illustrate example-

class Point.java

package com.test;

public class Point {
private int x,y;

public int getX() {
return x;
}

public void setX(int x) {
this.x = x;
}

public int getY() {
return y;
}

public void setY(int y) {
this.y = y;
}

}

class Triangle.java

package com.test;

import org.springframework.beans.BeansException;
import org.springframework.beans.factory.BeanNameAware;
import org.springframework.context.ApplicationContext;
import org.springframework.context.ApplicationContextAware;

public class Triangle implements ApplicationContextAware,BeanNameAware{

private Point point1;
private Draw dr;

public Point getPoint1() {
return point1;
}

public void setPoint1(Point point1) {
this.point1 = point1;
}
public void show()
{
System.out.println("Ponit1 x="+point1.getX()+"y="+point1.getY());
dr.draw();
}

public Draw getDr() {
return dr;
}

public void setDr(Draw dr) {
this.dr = dr;
}
@Override
public void setApplicationContext(ApplicationContext context)
throws BeansException {
System.out.println("context is="+context.toString());
}

@Override
public void setBeanName(String bean) {
System.out.println("bean name is="+bean);
}

}

class Draw.java

package com.test;

public class Draw {

public void draw()
{
System.out.println("Triangle Drawn");
}

}

class Main.java

Spring.xml

<?xml version="1.0" encoding="UTF-8"?>
<!DOCTYPE beans PUBLIC "-//SPRING//DTD BEAN 2.0//EN" "http://www.springframework.org/dtd/spring-beans-2.0.dtd">
<beans>
<bean id="point1" class="com.test.Point">
<property name="x" value="10"></property>
<property name="y" value="20"></property>
</bean>
<bean id="draw" class="com.test.Draw">
</bean>
<bean id="triangle" class="com.test.Triangle" autowire="autodetect">
</bean>
</beans>

Output is=

bean name is=triangle
context is=org.springframework.context.support.ClassPathXmlApplicationContext@1d6096: startup date [Mon Jun 25 10:38:24 IST 2012]; root of context hierarchy
Ponit1 x=10y=20
Triangle Drawn

Bean postprocessing in spring

2012-06-24T21:37:00.000-07:00

Spring provide two opportunities or us to cut into a bean's lifecycle and review or alter its configuration. this is called 'post processing'.The BeanPostProcessor interface gives two opportunities to alter a bean after it has been
created or wired.
public interface BeanPostProcessor
{
Object postProcessBeforeInitialization (Object bean,String name) throw BeanException;
Object postProcessAfterInitialization (Object bean,String name) throw BeanException;
}
The postProcessBeforeInitialization() method called before the bean initialization.likewise postProcessAfterInitialization () method called immediately after initialization.

Let see a example to understand -
Directory Structure-

Class Point.java

Class Triangle.java

package com.test;

public class Triangle {

private Point point1;
private Draw dr;

public Point getPoint1() {
return point1;
}

public void setPoint1(Point point1) {
this.point1 = point1;
}
public void show()
{
System.out.println("Ponit1 x="+point1.getX()+"y="+point1.getY());
dr.draw();
}

public Draw getDr() {
return dr;
}

public void setDr(Draw dr) {
this.dr = dr;
}
}

Class Draw.java

package com.test;

public class Draw {

public void draw()
{
System.out.println("Triangle Drawn");
}

}

Class BeanPostDisplay.java

package com.test;

import org.springframework.beans.BeansException;
import org.springframework.beans.factory.config.BeanPostProcessor;

public class BeanPostDisplay implements BeanPostProcessor {

@Override
public Object postProcessAfterInitialization(Object obj, String bean)
throws BeansException {
System.out.println("Initialization is complete of "+bean);
return obj;
}

@Override
public Object postProcessBeforeInitialization(Object obj, String bean)
throws BeansException {
System.out.println("Initialization is Started of "+bean);
return obj;
}
}

Class Main.java

Initialization is Started of point1
Initialization is complete of point1
Initialization is Started of draw
Initialization is complete of draw
Initialization is Started of triangle
Initialization is complete of triangle
Ponit1 x=10y=20
Triangle Drawn

Create beans with factory method (singleton class) in spring

2012-06-18T12:05:00.000-07:00

Mostly the beans that are configure in the spring application context will be created by calling one of the class's constructor.
In the case of configuring singleton class(class that only create one instance) or bean allowing throw factory method.
Here illustrate a example to understand it-
Directory Structure-

Class FactoryBean.java

package com.test;

public class FactoryBean {
private String name;

public String getName() {
return name;
}
public void setName(String name) {
this.name = name;
}
private FactoryBean(){}

private static class SingaltonClass // inner class who create only single instance
{
static FactoryBean instance=new FactoryBean();
}
public static FactoryBean getInstance() // factory method to create instance
{
return SingaltonClass.instance;

}
public void show()
{
System.out.println("Name is="+name);
}

}

class Main.java

spring.xml

<?xml version="1.0" encoding="UTF-8"?>
<!DOCTYPE beans PUBLIC "-//SPRING//DTD BEAN 2.0//EN" "http://www.springframework.org/dtd/spring-beans-2.0.dtd">
<beans>
<bean id="factoryBean" class="com.test.FactoryBean" factory-method="getInstance">
<property name="name" value="Factory Beans"></property>
</bean>
</beans>

Output is=

Name is=Factory Beans

Spring Framework- Event Handling

2012-06-17T10:34:00.001-07:00

Spring Framework also provide an another feature to promote loose coupling ,which is Application Event handling. Using Events, an Event publisher object can communicate with other objects without even knowing which object is listen.and event listener can work to event without knowing which object publish the events. Publisher Object that object ,who publish the event or call the event and Listener always listen the events that are occurs.
To make a custom event extends the class with ApplicationEvent class.The ApplicationEventPublisher has contain publishEvent() method that enable to publish ApplicationEvents (Custom Events).Any ApplicationListener that is registered with the onApplicationEvent() method in application,listen the events.
To understand The Event handling Lets illustrate a simple example-
Directory Structure-

Class Point.java

package com.test;

public class Point {
int x,y;
public int getX() {
return x;
}
public void setX(int x) {
this.x = x;
}
public int getY() {
return y;
}
public void setY(int y) {
this.y = y;
}
}

Class Tri.java

package com.test;

import org.springframework.beans.factory.annotation.Autowired;
import org.springframework.context.ApplicationEventPublisher;
import org.springframework.context.ApplicationEventPublisherAware;

public class Tri implements ApplicationEventPublisherAware{
ApplicationEventPublisher Ae;
Point p;

public Point getP() {
return p;
}

@Autowired
public void setP(Point p) {
this.p = p;
}
public void show()
{
System.out.println("x="+p.getX());
System.out.println("y="+p.getY());
Ae.publishEvent(new ShowEvent(this)); // Publish the event with publishEvent()
}

@Override
public void setApplicationEventPublisher(ApplicationEventPublisher Ae) {
this.Ae=Ae;
}
}

Class MyListener.java

package com.test;

import org.springframework.context.ApplicationEvent;
import org.springframework.context.ApplicationListener;
import org.springframework.stereotype.Component;
@SuppressWarnings("rawtypes")
@Component
public class MyListener implements ApplicationListener{ // define Listener

@Override
public void onApplicationEvent(ApplicationEvent e) {
System.out.println(e.toString());
}

}

Class ShowEvent.java

package com.test;

import org.springframework.context.ApplicationEvent;
public class ShowEvent extends ApplicationEvent {// Craete Event with event class

private static final long serialVersionUID = 1L;
public ShowEvent(Object source) {
super(source);
}

public String toString()
{
return("Hurry!!!!!Show Event occurs ");
}
}

Class Draw.java

package com.test;

import org.springframework.context.ApplicationContext;
import org.springframework.context.support.ClassPathXmlApplicationContext;

public class Draw {

public static void main(String[] args) {
ApplicationContext context=new ClassPathXmlApplicationContext("spring.xml");
Tri t=(Tri) context.getBean("tri");
t.show();
}
}
Spring.xml

<?xml version="1.0" encoding="UTF-8"?>
<beans xmlns="http://www.springframework.org/schema/beans"
xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
xsi:schemaLocation="http://www.springframework.org/schema/beans http://www.springframework.org/schema/beans/spring-beans.xsd
http://www.springframework.org/schema/context http://www.springframework.org/schema/context/spring-context.xsd"
xmlns:context="http://www.springframework.org/schema/context">
<context:annotation-config/>
<bean id="p" class="com.test.Point">
<property name="x" value="10"></property>
<property name="y" value="20"></property>
</bean>
<bean id="tri" class="com.test.Tri">
</bean>
<context:component-scan base-package="com.test"></context:component-scan>
</beans>

Output is=

x=10
y=20
Hurry!!!!!Show Event occurs

What is difference between id and name of bean?

2012-06-16T00:33:00.000-07:00

id of bean is a unique in container for each bean . id is basically used to access the bean anywhere. but it not accept the url matching like in spring framework. name is partially work like id but it can accept url matching.
example-
<bean name="/*.html" class="com.test.handler">
In web application when url contain this pattern it call that class. The id is not preferred for that feature. It caught a exception at the run time.