Spring

ORM Frameworks

ORM Frameworks

Spring gives API to effectively incorporate Spring with ORM structures, for example, Hibernate, JPA(Java Persistence API), JDO(Java Data Objects), Oracle Toplink and iBATIS.

Advantage of ORM Frameworks with Spring

Less coding is required
Easy to test
Better exception handling Integrated transaction management

Hibernate and Spring Integration

We can just incorporate rest application with spring application.hibernate structure, we give all the database data hibernate.cfg.xml document.

Yet, in the event that we will incorporate the sleep application with spring, we don’t have to make the hibernate.cfg.xml record. We can give all the data in the applicationContext.xml document.

Favorable position of Spring system with hibernate

The Spring structure gives HibernateTemplate class, so you don’t have to take after such a large number of steps like make Configuration, BuildSessionFactory, Session, starting and submitting exchange.

Methods of HibernateTemplate class

No.	Method
1)	void persist(Object entity)
2)	Serializable save(Object entity)
3)	void saveOrUpdate(Object entity)
4)	void update(Object entity)
5)	void delete(Object entity)
6)	Object get(Class entityClass, Serializable id)
7)	Object load(Class entityClass, Serializable id)
8)	List loadAll(Class entityClass)

Steps

create table in the database
create applicationContext.xml file
create Employee.java file
create employee.hbm.xml file
create EmployeeDao.java file
create InsertTest.java file
create the table in the database

CREATE TABLE “EMP558”

( “ID” NUMBER(10,0) NOT NULL ENABLE,

“NAME” VARCHAR2(255 CHAR),

“SALARY” FLOAT(126),

PRIMARY KEY (“ID”) ENABLE

)

2) Employee.java

package com.javaspot;

public class Employee {

private int id;

private String name;

private float salary;

//getters and setters

}

3) employee.hbm.xml

<?xml version=’1.0′ encoding=’UTF-8′?>

<!DOCTYPE hibernate-mapping PUBLIC

“-//Hibernate/Hibernate Mapping DTD 3.0//EN”

“http://hibernate.sourceforge.net/hibernate-mapping-3.0.dtd”>

<hibernate-mapping>

<class name=”com.javaspot.Employee” table=”emp558″>

</id>

</class>

</hibernate-mapping>

4) EmployeeDao.java

package com.javaspot;

import org.springframework.orm.hibernate3.HibernateTemplate;

import java.util.*;

public class EmployeeDao {

HibernateTemplate template;

public void setTemplate(HibernateTemplate template) {

this.template = template;

}

//method to save employee

public void saveEmployee(Employee e){

template.save(e);

}

//method to update employee

public void updateEmployee(Employee e){

template.update(e);

}

//method to delete employee

public void deleteEmployee(Employee e){

template.delete(e);

}

//method to return one employee of given id

public Employee getById(int id){

Employee e=(Employee)template.get(Employee.class,id);

return e;

}

//method to return all employees

public List<Employee> getEmployees(){

List<Employee> list=new ArrayList<Employee>();

list=template.loadAll(Employee.class);

return list;

}

5) applicationContext.xml

File: applicationContext.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:p=”http://www.springframework.org/schema/p”

xsi:schemaLocation=”http://www.springframework.org/schema/beans

http://www.springframework.org/schema/beans/spring-beans-3.0.xsd”>

</bean>

<list>

<value>employee.hbm.xml</value>

</list>

</property>

<props>

<prop key=”hibernate.dialect”>org.hibernate.dialect.Oracle9Dialect</prop>

<prop key=”hibernate.hbm2ddl.auto”>update</prop>

</props>

</property>

</bean>

</bean>

</bean>

</beans>

6) InsertTest.java

package com.javaspot;

import org.springframework.beans.factory.BeanFactory;

import org.springframework.beans.factory.xml.XmlBeanFactory;

import org.springframework.core.io.ClassPathResource;

import org.springframework.core.io.Resource;

public class InsertTest {

public static void main(String[] args) {

Resource r=new ClassPathResource(“applicationContext.xml”);

BeanFactory factory=new XmlBeanFactory(r);

EmployeeDao dao=(EmployeeDao)factory.getBean(“d”);

Employee e=new Employee();

e.setId(114);

e.setName(“varun”);

e.setSalary(50000);

dao.saveEmployee(e);

}

<props>

<prop key=”hibernate.dialect”>org.hibernate.dialect.Oracle9Dialect</prop>

<prop key=”hibernate.hbm2ddl.auto”>update</prop>

</props>

Spring Data JPA

Spring Data JPA API gives JpaTemplate class to coordinate spring application with JPA.

JPA (Java Persistent API) is the sun determination for holding on objects in the endeavor application. It is at present utilized as the substitution for complex element beans.

The usage of JPA determination are given by numerous merchants

Hibernate
Toplink
iBatis
OpenJPA

Advantage of Spring JpaTemplate

You don’t have to write the prior code and then afterward code for continuing, refreshing, erasing or seeking article, for example, making Persistence occurrence, making EntityManagerFactory case, making Entity Transaction case, making Entity Manager occasion, commiting Entity Transaction case and shutting Entity Manager.

Example of Spring and JPA Integration

create Account.java file
create Account.xml file
create AccountDao.java file
create persistence.xml file
create applicationContext.xml file
create AccountsClient.java file

Spring Expression Language (SPEL)

SpEL is an expression dialect supporting the elements of questioning and controlling a protest diagram at runtime.

There are numerous articulation dialects accessible, for example, JSP EL, OGNL, MVEL and JBoss EL. SpEL gives some extra elements, for example, strategy summon and string templating usefulness.

SpEL API

Expression interface
SpelExpression class
ExpressionParser interface
SpelExpressionParser class
EvaluationContext interface
StandardEvaluationContext class

Operators in SPEL

Examples of using operators in SPEL

import org.springframework.expression.ExpressionParser;

import org.springframework.expression.spel.standard.SpelExpressionParser;

public class Test {

public static void main(String[] args) {

ExpressionParser parser = new SpelExpressionParser();

//arithmetic operator

System.out.println(parser.parseExpression(“‘Welcome SPEL’+’!'”).getValue());

System.out.println(parser.parseExpression(“10 * 10/2”).getValue());

System.out.println(parser.parseExpression(“‘Today is: ‘+ new java.util.Date()”).getValue());

//logical operator

System.out.println(parser.parseExpression(“true and true”).getValue());

//Relational operator

System.out.println(parser.parseExpression(“‘sonoo’.length()==5”).getValue());

}

Variable in SPEL | StandardEvaluationContext:

Variable in a SPEL is it can store a value in a variable and that is used in method and call the method.For working on this we must use StandardEvaluationContext class.

Example of Using variable in SPEL

Calculation.java

public class Calculation {

private int number;

public int getNumber() {

return number;

}

public void setNumber(int number) {

this.number = number;

}

public int cube(){

return number*number*number;

}

}
Test.java

import org.springframework.expression.ExpressionParser;

import org.springframework.expression.spel.standard.SpelExpressionParser;

import org.springframework.expression.spel.support.StandardEvaluationContext;

public class Test {

public static void main(String[] args) {

Calculation calculation=new Calculation();

StandardEvaluationContext context=new StandardEvaluationContext(calculation);

ExpressionParser parser = new SpelExpressionParser();

parser.parseExpression(“number”).setValue(context,”5″);

System.out.println(calculation.cube());

}

Spring MVC

Spring MVC instructional exercise gives an exquisite answer for utilize MVC in spring system by the assistance of DispatcherServlet.

In Spring Web MVC, DispatcherServlet class fills in as the front controller. It is dependable to deal with the stream of the spring mvc application.

The @Controller comment is utilized to stamp the class as the controller in Spring 3.

The @RequestMapping comment is utilized to outline ask for url.

Flow of Spring Web MVC:

Spring Web MVC Framework

Create the request page (optional)
Create the controller class
Provide the entry of controller in the web.xml file
Define the bean in the xml file
Display the message in the JSP page
Load the spring core and mvc jar files
Start server and deploy the project

Required Jar files or Maven Dependency

To run this example, you need to load:

Spring Core jar files
Spring Web jar files

1) Create the request page (optional)

index.jsp

<a href=”hello.html”>click</a>

2) Create the controller class

The @Controller annotation.

The @Requestmapping annotation

WelcomeWorldController.java

package com.javaspot;

import org.springframework.stereotype.Controller;

import org.springframework.web.bind.annotation.RequestMapping;

import org.springframework.web.servlet.ModelAndView;

@Controller

public classWelcomeWorldController {

@RequestMapping(“/hello”)

public ModelAndView helloWorld() {

String message = “HELLO SPRING MVC HOW R U”;

return new ModelAndView(“hellopage”, “message”, message);

}

3) Provide the entry of controller in the web.xml file

web.xml

<?xml version=”1.0″ encoding=”UTF-8″?>

<web-app version=”2.5″

xmlns=”http://java.sun.com/xml/ns/javaee”

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

xsi:schemaLocation=”http://java.sun.com/xml/ns/javaee

http://java.sun.com/xml/ns/javaee/web-app_2_5.xsd”>

<servlet-name>spring</servlet-name>

<servlet-class>org.springframework.web.servlet.DispatcherServlet</servlet-class>

<load-on-startup>1</load-on-startup>

</servlet>

<servlet-mapping>

<servlet-name>spring</servlet-name>

<url-pattern>*.html</url-pattern>

</servlet-mapping>

</web-app>

4) Define the bean in the xml file

This is the essential setup record where we have to determine the ViewResolver and View parts.

The context:component-scan component characterizes the base-bundle where DispatcherServlet will look through the controller class.

Here, the InternalResourceViewResolver class is utilized for the ViewResolver.

The prefix+string returned by controller+suffix page will be conjured for the view part.

This xml document ought to be situated inside the WEB-INF index.

spring-servlet.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:p=”http://www.springframework.org/schema/p”

xmlns:context=”http://www.springframework.org/schema/context”

xsi:schemaLocation=”http://www.springframework.org/schema/beans

http://www.springframework.org/schema/beans/spring-beans-3.0.xsd

http://www.springframework.org/schema/context

http://www.springframework.org/schema/context/spring-context-3.0.xsd”>

<context:component-scan base-package=”com.javaspot” />

</bean>

</beans>

5) Display the message in the JSP page

hellopage.jsp

Message is: ${message}

<groupId>com.javaspot</groupId>

<artifactId>SpringMVC</artifactId>

Spring 3 MVC Multiple Controller Example

1) Controller Classes

WelcomeWorldController.java

package com.javaspot;

import org.springframework.stereotype.Controller;

import org.springframework.web.bind.annotation.RequestMapping;

import org.springframework.web.servlet.ModelAndView;

@Controller

public class WelcomeWorldController {

@RequestMapping(“/welcome”)

public ModelAndView welcomeWorld() {

String message = “WELCOME SPRING MVC”;

return new ModelAndView(“welcomepage”, “message”, message);

}

2) View components

hellopage.jsp

Message is: ${message}

welcomepage.jsp

Message is: ${message}

3) Index page

index.jsp

<a href=”hello.html”>click</a>|

<a href=”welcome.html”>click</a>

Spring MVC Request Response Example

Controller Class

HelloWorldController.java

package com.javaspot;

import javax.servlet.http.HttpServletRequest;

import javax.servlet.http.HttpServletResponse;

import org.springframework.stereotype.Controller;

import org.springframework.web.bind.annotation.RequestMapping;

import org.springframework.web.servlet.ModelAndView;

@Controller

public class HelloWorldController {

@RequestMapping(“/hello”)

public ModelAndView helloWorld(HttpServletRequest request,HttpServletResponse res) {

String name=request.getParameter(“name”);

String password=request.getParameter(“password”);

if(password.equals(“admin”)){

String message = “HELLO “+name;

return new ModelAndView(“hellopage”, “message”, message);

}

else{

return new ModelAndView(“errorpage”, “message”,”Sorry, username or password error”);

}

2) View components

hellopage.jsp

Message is: ${message}

errorpage.jsp

${message}

<jsp:include page=”/index.jsp”></jsp:include>

3) Index page

.index.jsp

Name:<input type=”text” name=”name”/><br/>

Password:<input type=”password” name=”password”/><br/>

</form>

spring MVC File Upload Example

Required Jar files

To run this example, you need to load:

Spring Core jar files
Spring Web jar files
commons-fileupload.jar and commons-io.jar file

Spring MVC File Upload Steps (Extra than MVC)

1) Add commons-io and fileupload.jar files

2) Add entry of CommonsMultipartResolver in spring-servlet.xml

<bean id=”multipartResolver”

class=”org.springframework.web.multipart.commons.CommonsMultipartResolver”/>

3) Create form to submit file. Method name must be “post” and enctype “multiple/form-data”.

<form action=”savefile” method=”post” enctype=”multipart/form-data”>

Select File: <input type=”file” name=”file”/>

<input type=”submit” value=”Upload File”/>

</form>

4) Use CommonsMultipartFile class in Controller.

@RequestMapping(value=”/savefile”,method=RequestMethod.POST)

public ModelAndView upload(@RequestParam CommonsMultipartFile file,HttpSession session){

String path=session.getServletContext().getRealPath(“/”);

String filename=file.getOriginalFilename();

System.out.println(path+” “+filename);

try{

byte barr[]=file.getBytes();

BufferedOutputStream bout=new BufferedOutputStream(

new FileOutputStream(path+”/”+filename));

bout.write(barr);

bout.flush();

bout.close();

}catch(Exception e){System.out.println(e);}

return new ModelAndView(“upload-success”,”filename”,path+”/”+filename);

}

5) Display image in JSP.

<h1>Upload Success</h1>

<img src=”${filename}”/>

Spring MVC File Upload Example

Create images directory

index.jsp

<a href=”uploadform”>Upload Image</a>

Emp.java

package com.javaspot;

import java.io.BufferedOutputStream;

import java.io.File;

import java.io.FileOutputStream;

import javax.servlet.ServletContext;

import javax.servlet.http.HttpServletRequest;

import javax.servlet.http.HttpServletResponse;

import javax.servlet.http.HttpSession;

import org.apache.commons.fileupload.disk.DiskFileItemFactory;

import org.apache.commons.fileupload.servlet.ServletFileUpload;

import org.springframework.stereotype.Controller;

import org.springframework.web.bind.annotation.ModelAttribute;

import org.springframework.web.bind.annotation.RequestMapping;

import org.springframework.web.bind.annotation.RequestMethod;

import org.springframework.web.bind.annotation.RequestParam;

import org.springframework.web.multipart.commons.CommonsMultipartFile;

import org.springframework.web.servlet.ModelAndView;

@Controller

public class HelloController {

private static final String UPLOAD_DIRECTORY =”/images”;

@RequestMapping(“uploadform”)

public ModelAndView uploadForm(){

return new ModelAndView(“uploadform”);

}

@RequestMapping(value=”savefile”,method=RequestMethod.POST)

public ModelAndView saveimage( @RequestParam CommonsMultipartFile file,

HttpSession session) throws Exception{

ServletContext context = session.getServletContext();

String path = context.getRealPath(UPLOAD_DIRECTORY);

String filename = file.getOriginalFilename();

System.out.println(path+” “+filename);

byte[] bytes = file.getBytes();

BufferedOutputStream stream =new BufferedOutputStream(new FileOutputStream(

new File(path + File.separator + filename)));

stream.write(bytes);

stream.flush();

stream.close();

return new ModelAndView(“uploadform”,”filesuccess”,”File successfully saved!”);

}

web.xml

<?xml version=”1.0″ encoding=”UTF-8″?>

<web-app version=”2.5″

xmlns=”http://java.sun.com/xml/ns/javaee”

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

xsi:schemaLocation=”http://java.sun.com/xml/ns/javaee

http://java.sun.com/xml/ns/javaee/web-app_2_5.xsd”>

<servlet-name>spring</servlet-name>

<servlet-class>org.springframework.web.servlet.DispatcherServlet</servlet-class>

<load-on-startup>1</load-on-startup>

</servlet>

<servlet-mapping>

<servlet-name>spring</servlet-name>

<url-pattern>/</url-pattern>

</servlet-mapping>

</web-app>

spring-servlet.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:p=”http://www.springframework.org/schema/p”

xmlns:context=”http://www.springframework.org/schema/context”

xsi:schemaLocation=”http://www.springframework.org/schema/beans

http://www.springframework.org/schema/beans/spring-beans-3.0.xsd

http://www.springframework.org/schema/context

http://www.springframework.org/schema/context/spring-context-3.0.xsd”>

<context:component-scan base-package=”com.javaspot”></context:component-scan>

</bean>

<bean id=”multipartResolver”

class=”org.springframework.web.multipart.commons.CommonsMultipartResolver”/>

</beans>

uploadform.jsp

Here form must be method=”post” and enctype=”multipart/form-data”.

<%@taglib uri=”http://www.springframework.org/tags/form” prefix=”form”%>

<!DOCTYPE html>

<html>

<head>

<title>Image File Upload</title>

</head>

<body>

<h1>File Upload Example – Javaspot</h1>

<h3 style=”color:red”>${filesuccess}</h3>

<form:form method=”post” action=”savefile” enctype=”multipart/form-data”>

<p><label for=”image”>Choose Image</label></p>

</form:form>

</body>

</html>

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