User

package com.saatwik.domain;

import java.io.Serializable;

import javax.persistence.Entity; import javax.persistence.GeneratedValue; import javax.persistence.Id;

@Entity public class User implements Serializable {

   private static final long serialVersionUID = 1L;
   
   @Id
   @GeneratedValue
   private long id;
   
   private String username;

public long getId() { return id; }

public void setId(long id) { this.id = id; }

public String getUsername() { return username; }

public void setUsername(String username) { this.username = username; }

}

AbstractRepository

package com.saatwik.repository;

import javax.persistence.EntityManager; import javax.persistence.PersistenceContext;

public class AbstractRepository<T> {

@PersistenceContext

   protected EntityManager entityManager;
   
   public T persist(T t) {
       
       entityManager.persist(t);
       
       return t;
   }
   
   public T merge(T t) {
       
       return entityManager.merge(t);
   }
   
   public void remove(T t) {
       
       entityManager.remove(t);
   }

}

UserRepository package com.saatwik.repository;

import java.util.List;

import org.springframework.stereotype.Repository;

import com.saatwik.domain.User;

@Repository("userRepository") public class UserRepository extends AbstractRepository<User> {

@SuppressWarnings("unchecked") public List<User> getAll() {

return entityManager.createQuery( "SELECT u FROM User u ORDER BY u.username").getResultList();

}

UserService

package com.saatwik.service;

import java.util.List;

import com.saatwik.domain.User;

public interface UserService {

List<User> getAll() throws Exception;

User create(User user) throws Exception;

}

UserServiceImpl

package com.saatwik.service;

import java.text.ParseException; import java.util.List;

import org.springframework.beans.factory.annotation.Autowired; import org.springframework.stereotype.Service; import org.springframework.transaction.annotation.Transactional;

import com.saatwik.domain.User; import com.saatwik.repository.UserRepository;

/**

* provides services for user.
*
*/

@Service("userService") @Transactional(readOnly = true) public class UserServiceImpl implements UserService {

@Autowired private UserRepository userRepository;

public List<User> getAll() {

return userRepository.getAll(); }

@Transactional(readOnly = false) public User create(User user) throws ParseException {

return userRepository.merge(user);

}

HomeController

package com.saatwik.web;

import java.util.HashMap; import java.util.List; import java.util.Map;

import org.springframework.beans.factory.annotation.Autowired; import org.springframework.stereotype.Controller; import org.springframework.util.StringUtils; import org.springframework.web.bind.annotation.ModelAttribute; import org.springframework.web.bind.annotation.RequestMapping; import org.springframework.web.servlet.ModelAndView;

import com.saatwik.domain.User; import com.saatwik.service.UserService;

@Controller @RequestMapping(value = { "" }) public class HomeController {

@Autowired private UserService userService;

@RequestMapping(value = { "", "/" }) public ModelAndView home() throws Exception {

Map<String, Object> params = new HashMap<String, Object>();

List<User> users = userService.getAll();

params.put("users", users);

params.put("user", new User());

return new ModelAndView("home", params); }

@RequestMapping("/save") public ModelAndView save(@ModelAttribute("user") User user) throws Exception {

Map<String, Object> params = new HashMap<String, Object>();

if (!StringUtils.hasText(user.getUsername())) {

params.put("usernameMessage", "Input required");

return new ModelAndView("home", params);

}

userService.create(user);

return new ModelAndView("redirect:/"); } }

src/META-INF/persistence.xml

<?xml version="1.0" encoding="UTF-8"?> <persistence version="1.0" xmlns="http://java.sun.com/xml/ns/persistence" xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance" xsi:schemaLocation="http://java.sun.com/xml/ns/persistence http://java.sun.com/xml/ns/persistence/persistence_1_0.xsd">

 <persistence-unit name="jpa-example-PU" transaction-type="RESOURCE_LOCAL">

<class>com.saatwik.domain.User</class>

   <exclude-unlisted-classes>false</exclude-unlisted-classes>
   
 </persistence-unit>

</persistence>

src/jdbc.properties

1. 1. LOCAL

jdbc.driver=com.mysql.jdbc.Driver jdbc.url=jdbc:mysql://10.1.55.55:3306/demodb jdbc.username=root jdbc.password=root123

web-inf/jpa-example-servlet

   <context:property-placeholder location="classpath:jdbc.properties" />
   
   <import resource="persistenceContext.xml" />

<context:annotation-config />

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

<mvc:annotation-driven />

<bean id="jspViewResolver" class="org.springframework.web.servlet.view.InternalResourceViewResolver"

   		p:prefix="/WEB-INF/view/" p:suffix=".jsp" p:order="1"/>

</beans>

web-inf/persistenceContext.xml

<?xml version="1.0" encoding="UTF-8"?> <beans xmlns="http://www.springframework.org/schema/beans"

      xmlns:mvc="http://www.springframework.org/schema/mvc"
      xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
      xmlns:aop="http://www.springframework.org/schema/aop"
      xmlns:context="http://www.springframework.org/schema/context"
      xmlns:tx="http://www.springframework.org/schema/tx"
      xmlns:util="http://www.springframework.org/schema/util"
      xsi:schemaLocation="http://www.springframework.org/schema/beans http://www.springframework.org/schema/beans/spring-beans-3.0.xsd
         http://www.springframework.org/schema/aop http://www.springframework.org/schema/aop/spring-aop-3.0.xsd
         http://www.springframework.org/schema/context http://www.springframework.org/schema/context/spring-context-3.0.xsd
         http://www.springframework.org/schema/tx http://www.springframework.org/schema/tx/spring-tx-3.0.xsd
         http://www.springframework.org/schema/mvc http://www.springframework.org/schema/mvc/spring-mvc-3.0.xsd
         http://www.springframework.org/schema/util http://www.springframework.org/schema/util/spring-util-3.0.xsd">
             
   <tx:annotation-driven transaction-manager="transactionManager"/>

   <bean class="org.springframework.orm.jpa.support.PersistenceAnnotationBeanPostProcessor" />

   <bean id="dataSource" class="org.springframework.jdbc.datasource.DriverManagerDataSource">
       <property name="driverClassName" value="${jdbc.driver}" />
       <property name="url" value="${jdbc.url}"/>
       <property name="username" value="${jdbc.username}"/>
       <property name="password" value="${jdbc.password}"/>
   </bean>

   <bean id="transactionManager" class="org.springframework.orm.jpa.JpaTransactionManager">
       <property name="entityManagerFactory" ref="entityManagerFactory" />
   </bean>
      
   <bean id="jpaTemplate" class="org.springframework.orm.jpa.JpaTemplate"> 
       <property name="entityManagerFactory" ref="entityManagerFactory" />
   </bean>
      
   <bean id="entityManagerFactory" class="org.springframework.orm.jpa.LocalContainerEntityManagerFactoryBean">
       <property name="dataSource" ref="dataSource" />
       <property name="jpaVendorAdapter" ref="jpaAdapter" />
       <property name="persistenceUnitName" value="jpa-example-PU" />
       <property name="loadTimeWeaver">
           <bean class="org.springframework.instrument.classloading.InstrumentationLoadTimeWeaver" />
       </property>
   </bean>

   <bean id="jpaAdapter" class="org.springframework.orm.jpa.vendor.HibernateJpaVendorAdapter">
       <property name="databasePlatform" value="org.hibernate.dialect.MySQL5InnoDBDialect" /> 
       <property name="generateDdl" value="true" />
       <property name="showSql" value="false" />
   </bean>

</beans>

web-inf/view/home.jsp

<%@ page language="java" contentType="text/html; charset=ISO-8859-1"

   pageEncoding="ISO-8859-1"%>

<%@ taglib prefix="c" uri="http://java.sun.com/jsp/jstl/core" %> <%@ taglib prefix="form" uri="http://www.springframework.org/tags/form" %> <!DOCTYPE html PUBLIC "-//W3C//DTD HTML 4.01 Transitional//EN" "http://www.w3.org/TR/html4/loose.dtd"> <html> <head> <meta http-equiv="Content-Type" content="text/html; charset=ISO-8859-1"> <title>JPA - Hibernate Example</title> </head>

<body>

JPA - Hibernate Example

Add User:

<form:form method="post" modelAttribute="user" action="save">

<label>Username: </label> <form:input class="input-small" path="username" /> <label>${usernameMessage}</label>

</form:form>

List of Users

<c:forEach items="${users}" var="userVar" varStatus="status"> </c:forEach>

ID	Username
${userVar.id}	${userVar.username}

</body> </html>

web.xml

<?xml version="1.0" encoding="UTF-8"?> <web-app xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance" xmlns="http://java.sun.com/xml/ns/j2ee" xmlns:javaee="http://xmlns.jcp.org/xml/ns/javaee" xmlns:web="http://xmlns.jcp.org/xml/ns/javaee" xsi:schemaLocation="http://java.sun.com/xml/ns/j2ee http://java.sun.com/xml/ns/j2ee/web-app_2_4.xsd http://xmlns.jcp.org/xml/ns/javaee http://java.sun.com/xml/ns/javaee/web-app_2_5.xsd" id="WebApp_ID" version="2.4">

 <display-name>jpa-example</display-name>
 <servlet>
   <servlet-name>jpa-example</servlet-name>
   <servlet-class>org.springframework.web.servlet.DispatcherServlet</servlet-class>
 </servlet>
 <servlet-mapping>
   <servlet-name>jpa-example</servlet-name>
   <url-pattern>/</url-pattern>
 </servlet-mapping>

</web-app>