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Spring 4 with JPA (Hibernate 4/EclipseLink)

lgscofield
 lgscofield
发布于 2015/04/17 20:59
字数 1854
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Java Persistence API is a standard specification. It provides a persistence model that’s implemented by different numerous of implementer.

Hibernate & EclipseLink are two most popular implementations used for persisting given business model against some sort of persistence store like relational database. As such, this tutorial will provide you a full-fledged example containing all required configuration steps to developer a layered application that uses:

  • Primefaces components to develop a compelling User Interface that aimed to handle user’s interactions and verify user’s inputs.
  • Hibernate/EclipseLink implementations to develop an Object/Relational Mapping beneath JPA umbrella.
  • Spring framework as a kind of glue that get everything attached each together.

We’ve discussed before using of Hibernate ORM for persisting given domain classes in a multiple tutorials but today we will use only JPA based configurations. JPA specification does its bootstrap in a different way. In hibernate we’ve bootstrapped our application by using hibernate.cfg.xml file, but JPA doesn’t specify such that file. As such, JPA provides another way of configuration, it’s using of persistence.xml file which located within your classpath and under META-INF folder. Let’s see how can we use both of Hibernate andEclipseLink for implementing a single registration form.

Required Tools

Before proceeding far away, you must prepare your environments that should contain for:

  • JDK 1.6+.
  • Eclipse Kepler 4.3.
  • Hibernate 4.3.6.Final.
  • Spring 4.0.3.RELEASE.
  • EclipseLink 2.5.0-RC1
  • Maven Build Tool
  • MySQL 5.x.

Final Project Structure

Primefaces-Spring-JPA-Hibernate-EclipseLink-Project

Database Tables

We have Employee table in our MySQL database, you can use below script to create it.

Database Tables - Create Employee Table

CREATE TABLE `employee` (
  `EMP_ID` int(11) NOT NULL AUTO_INCREMENT,
  `EMP_NAME` varchar(45) DEFAULT NULL,
  `EMP_HIRE_DATE` datetime DEFAULT NULL,
  `EMP_SALARY` decimal(11,4) DEFAULT NULL,
  PRIMARY KEY (`EMP_ID`)
) ENGINE=InnoDB AUTO_INCREMENT=1 DEFAULT CHARSET=utf8;
  • Employee Table contains one Primary Key with Auto Increment value.

Domain Classes

We have also one domain class that would be persisting into our database Employee table.

package com.journaldev.hibernate.jpa.data;

import java.util.Date;

import javax.persistence.Column;
import javax.persistence.Entity;
import javax.persistence.Id;
import javax.persistence.Temporal;
import javax.persistence.TemporalType;
@Entity
public class Employee {
	@Id
	@Column(name="EMP_ID")
	private long employeeId;
	@Column(name="EMP_NAME")
	private String employeeName;
	@Column(name="EMP_HIRE_DATE")
	@Temporal(TemporalType.TIMESTAMP)
	private Date employeeHireDate;
	@Column(name="EMP_SALARY")
	private double employeeSalary;

	public long getEmployeeId() {
		return employeeId;
	}

	public void setEmployeeId(long employeeId) {
		this.employeeId = employeeId;
	}

	public String getEmployeeName() {
		return employeeName;
	}

	public void setEmployeeName(String employeeName) {
		this.employeeName = employeeName;
	}

	public Date getEmployeeHireDate() {
		return employeeHireDate;
	}

	public void setEmployeeHireDate(Date employeeHireDate) {
		this.employeeHireDate = employeeHireDate;
	}

	public double getEmployeeSalary() {
		return employeeSalary;
	}

	public void setEmployeeSalary(double employeeSalary) {
		this.employeeSalary = employeeSalary;
	}
}
  • JPA provides @Entity which will be used for indicating Employee as a persistent domain class. Default mapping would be happening in order to map this persistent entity with its Employee Table. In case you’ve provided Table name or class name that aren’t identical, @Table must be used.
  • @Id annotation used for indicating identity of a given Employee instance. Because of discrepancies between attribute name and column name, @column must be provided.
  • @Column name annotation takes a parameter of mapped column name.

Persistence Unit

As we’ve mentioned earlier, JPA provides an alternative way for bootstrapping JPA framework, it’s apersistence.xml file. The minimum amount of this file should look like:

<persistence 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_2_0.xsd"
	version="2.0">
	<!-- Will be referenced in Spring Context File -->
	<persistence-unit name="jpa-persistence" transaction-type="RESOURCE_LOCAL">
		<class>com.journaldev.hibernate.jpa.data.Employee</class>
		<properties>
			<property name="javax.persistence.jdbc.url" value="jdbc:mysql://localhost:3306/journaldev" />
			<property name="javax.persistence.jdbc.user" value="pankaj" />
			<property name="javax.persistence.jdbc.driver" value="com.mysql.jdbc.Driver" />
			<property name="javax.persistence.jdbc.password" value="pankaj123" />
		</properties>
	</persistence-unit>
</persistence>

Persistence unit should define:

  • Persistence unit name. That name will be referenced by Spring context.
  • Transaction type – JPA implementation have the choice of managing the resource by itself (RESOURCE_LOCAL) or having them managed by the application server’s JTA implementation.
  • Information about database connection.

Maven Dependencies

All required libraries are listed within pom.xml file that’s read by Maven itself.

<project xmlns="http://maven.apache.org/POM/4.0.0" xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
	xsi:schemaLocation="http://maven.apache.org/POM/4.0.0 http://maven.apache.org/maven-v4_0_0.xsd">
	<modelVersion>4.0.0</modelVersion>
	<groupId>com.journaldev</groupId>
	<artifactId>Primefaces-Hibernate-JPA-Spring-Integration-Sample</artifactId>
	<packaging>war</packaging>
	<version>0.0.1-SNAPSHOT</version>
	<name>Primefaces-Hibernate-JPA-Spring-Integration-Sample Maven Webapp</name>
	<url>http://maven.apache.org</url>
	<repositories>
		<repository>
			<id>prime-repo</id>
			<name>PrimeFaces Maven Repository</name>
			<url>http://repository.primefaces.org</url>
			<layout>default</layout>
		</repository>
	</repositories>
	<dependencies>
		<dependency>
			<groupId>junit</groupId>
			<artifactId>junit</artifactId>
			<version>3.8.1</version>
			<scope>test</scope>
		</dependency>
		<!-- Servlet -->
		<dependency>
			<groupId>javax.servlet</groupId>
			<artifactId>servlet-api</artifactId>
			<version>2.5</version>
			<scope>provided</scope>
		</dependency>
		<!-- Faces Implementation -->
		<dependency>
			<groupId>com.sun.faces</groupId>
			<artifactId>jsf-impl</artifactId>
			<version>2.2.4</version>
		</dependency>
		<!-- Faces Library -->
		<dependency>
			<groupId>com.sun.faces</groupId>
			<artifactId>jsf-api</artifactId>
			<version>2.2.4</version>
		</dependency>
		<!-- Primefaces Version 5 -->
		<dependency>
			<groupId>org.primefaces</groupId>
			<artifactId>primefaces</artifactId>
			<version>5.0</version>
		</dependency>
		<!-- JSP Library -->
		<dependency>
			<groupId>javax.servlet.jsp</groupId>
			<artifactId>javax.servlet.jsp-api</artifactId>
			<version>2.3.1</version>
		</dependency>
		<!-- JSTL Library -->
		<dependency>
			<groupId>javax.servlet</groupId>
			<artifactId>jstl</artifactId>
			<version>1.1.2</version>
		</dependency>
		<!-- Hibernate 4.3.6 core library library -->
		<dependency>
			<groupId>org.hibernate</groupId>
			<artifactId>hibernate-core</artifactId>
			<version>4.3.6.Final</version>
		</dependency>
		<!-- Hibernate 4.3.6 JPA support -->
		<dependency>
			<groupId>org.hibernate</groupId>
			<artifactId>hibernate-entitymanager</artifactId>
			<version>4.3.6.Final</version>
		</dependency>
		<!-- MySQL driver connector library -->
		<dependency>
			<groupId>mysql</groupId>
			<artifactId>mysql-connector-java</artifactId>
			<version>5.1.31</version>
		</dependency>
		<!-- Spring ORM -->
		<dependency>
			<groupId>org.springframework</groupId>
			<artifactId>spring-orm</artifactId>
			<version>4.0.3.RELEASE</version>
		</dependency>
		<!-- Spring Web -->
		<dependency>
			<groupId>org.springframework</groupId>
			<artifactId>spring-webmvc</artifactId>
			<version>4.0.3.RELEASE</version>
		</dependency>
		<!-- Dependencies for Eclipse JPA Persistence API -->
		<dependency>
			<groupId>org.eclipse.persistence</groupId>
			<artifactId>eclipselink</artifactId>
			<version>2.5.0-RC1</version>
		</dependency>
	</dependencies>
	<build>
		<plugins>
			<plugin>
				<groupId>org.apache.maven.plugins</groupId>
				<artifactId>maven-compiler-plugin</artifactId>
				<configuration>
					<source>1.6</source>
					<target>1.6</target>
				</configuration>
			</plugin>
		</plugins>
	</build>
</project>

Hibernate/JPA Spring Configuration

Persisting using of JPA requires an instance of EntityManager. This instance can be acquired by configuring a proper Spring context.

<?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:tx="http://www.springframework.org/schema/tx"
	xmlns:context="http://www.springframework.org/schema/context"
	xmlns:aop="http://www.springframework.org/schema/aop" xmlns:util="http://www.springframework.org/schema/util"
	xsi:schemaLocation="http://www.springframework.org/schema/beans http://www.springframework.org/schema/beans/spring-beans.xsd http://www.springframework.org/schema/aop http://www.springframework.org/schema/aop/spring-aop.xsd http://www.springframework.org/schema/context  http://www.springframework.org/schema/context/spring-context-3.2.xsd http://www.springframework.org/schema/tx http://www.springframework.org/schema/tx/spring-tx-3.2.xsd">
	<!-- Enable Spring Annotation Configuration -->
	<context:annotation-config />
	<!-- Scan for all of Spring components such as Spring Service -->
	<context:component-scan base-package="com.journaldev.spring.service"></context:component-scan>

	<!-- Necessary to get the entity manager injected into the factory bean -->
	<bean class="org.springframework.orm.jpa.support.PersistenceAnnotationBeanPostProcessor" />	

	<!-- Define Hibernate JPA Vendor Adapter -->
	<bean id="jpaVendorAdapter"
		class="org.springframework.orm.jpa.vendor.HibernateJpaVendorAdapter">
		<property name="databasePlatform"
			value="org.hibernate.dialect.MySQLDialect" />
	</bean>	

	<!-- Entity Manager Factory -->
	<bean id="entityManagerFactory"
		class="org.springframework.orm.jpa.LocalEntityManagerFactoryBean">
		<property name="persistenceUnitName" value="hibernate.jpa"></property>
		<property name="jpaVendorAdapter" ref="jpaVendorAdapter" />
	</bean>

	<!-- Transaction Manager -->
	<bean id="transactionManager" class="org.springframework.orm.jpa.JpaTransactionManager">
		<property name="entityManagerFactory" ref="entityManagerFactory" />
	</bean>

	<!-- Detect @Transactional -->
	<tx:annotation-driven transaction-manager="transactionManager" />
</beans>
  • JPA require an entityManagerFactory object which is an instance of org.springframework.orm.jpa.LocalEntityFactoryBean. This instance must be provided with the name of persistenceUnit and a JPAVendorAdapter.
  • To use @Trasnactional annotation properly, TransactionManager should be defined.
  • Default name and location for Spring context configuration is applicationContext.xml and beneath ofWEB-INF folder.

EclipseLink/JPA Spring Configuration

Same configuration would be used for EclipseLink, a small change is required is to provide EclipseLink’s JPA vendor. Just change the jpaVendorAdapter bean to below and the JPA implementation used will be EclipseLink.

<!-- Define EclipseLink JPA Vendor Adapter -->
	<bean id="jpaVendorAdapter"
		class="org.springframework.orm.jpa.vendor.EclipseLinkJpaVendorAdapter">
		<property name="databasePlatform"
			value="org.eclipse.persistence.platform.database.MySQLPlatform" />
		<property name="generateDdl" value="false" />
		<property name="showSql" value="true" />
	</bean>

Primefaces Deployment Descriptor

Proper configuration of Spring requires adding of Spring listener into Primefaces’ deployment descriptorweb.xml application.

<?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/javaee" xmlns:web="http://java.sun.com/xml/ns/javaee/web-app_2_5.xsd"
	xsi:schemaLocation="http://java.sun.com/xml/ns/javaee

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

	id="WebApp_ID" version="2.5" metadata-complete="true">
	<servlet>
		<servlet-name>Faces Servlet</servlet-name>
		<servlet-class>javax.faces.webapp.FacesServlet</servlet-class>
		<load-on-startup>1</load-on-startup>
	</servlet>
	<servlet-mapping>
		<servlet-name>Faces Servlet</servlet-name>
		<url-pattern>/faces/*</url-pattern>
	</servlet-mapping>
	<servlet-mapping>
		<servlet-name>Faces Servlet</servlet-name>
		<url-pattern>*.xhtml</url-pattern>
	</servlet-mapping>
	<context-param>
		<description>State saving method: 'client' or 'server' (=default). See JSF Specification 2.5.2</description>
		<param-name>javax.faces.STATE_SAVING_METHOD</param-name>
		<param-value>client</param-value>
	</context-param>
	<listener>
		<listener-class>org.springframework.web.context.ContextLoaderListener</listener-class>
	</listener>
	<listener>
		<listener-class>com.sun.faces.config.ConfigureListener</listener-class>
	</listener>
</web-app>

Spring EmployeeService

Spring service is the interaction point between presentation layer and persistence layer. If you’re familiar with DAO, you can consider it something similar.

package com.journaldev.spring.service;

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

import org.springframework.stereotype.Component;
import org.springframework.transaction.annotation.Transactional;

import com.journaldev.hibernate.jpa.data.Employee;

@Component
public class EmployeeService {
	@PersistenceContext
	private EntityManager em;

	public EntityManager getEm() {
		return em;
	}

	public void setEm(EntityManager em) {
		this.em = em;
	}

	@Transactional
	public void register(Employee emp) {
		// Save employee
		this.em.persist(emp);
	}
}
  • EntityManager is injected using @PersistenceContext annotation. Even you’ve defined an instance of EntityManagerFactory, but a JPA implementation will be very smart to inject you an instance of EntityManager. EntityManager would be something similar for Session in Hibernate. In case you’ve invoked any of its CRUD operation within both of context and active transaction, your operation would be persisted against your persistence store. Note that em.persist() and using of @Transactional annotation upon register method.

Primefaces Managed Bean – RegisterEmployee

RegisterEmployee is a faces managed bean that’s used for handling user interaction and validation of user’s input.

package com.journaldev.prime.faces.beans;

import javax.faces.application.FacesMessage;
import javax.faces.bean.ManagedBean;
import javax.faces.bean.ManagedProperty;
import javax.faces.bean.SessionScoped;
import javax.faces.context.FacesContext;

import com.journaldev.jpa.data.Employee;
import com.journaldev.spring.service.EmployeeService;

@ManagedBean
@SessionScoped
public class RegisterEmployee {

	@ManagedProperty("#{employeeService}")
	private EmployeeService employeeService;

	private Employee employee = new Employee();

	public EmployeeService getEmployeeService() {
		return employeeService;
	}

	public void setEmployeeService(EmployeeService employeeService) {
		this.employeeService = employeeService;
	}

	public Employee getEmployee() {
		return employee;
	}

	public void setEmployee(Employee employee) {
		this.employee = employee;
	}

	public String register() {
		// Calling Business Service
		employeeService.register(employee);
		// Add message
		FacesContext.getCurrentInstance().addMessage(null,
				new FacesMessage("The Employee "+this.employee.getEmployeeName()+" Is Registered Successfully"));
		return "";
	}
}
  • Spring service EmployeeService is injected using Spring el-reslover that get declared with your faces-config.xml.
  • Register method would delegate the invocation into an injected EmployeeService instance. As such, EmployeeService would handle real registration.

Primefaces Employee Registration

<html xmlns="http://www.w3.org/1999/xhtml"
	xmlns:ui="http://java.sun.com/jsf/facelets"
	xmlns:h="http://java.sun.com/jsf/html"
	xmlns:f="http://java.sun.com/jsf/core"
	xmlns:p="http://primefaces.org/ui">
<h:head>
	<script name="jquery/jquery.js" library="primefaces"></script>
	<title>Register Employee</title>
</h:head>
<h:form>
	<p:growl id="messages"></p:growl>
	<p:panelGrid columns="2">
		<p:outputLabel value="Enter Employee Name:"></p:outputLabel>
		<p:inputText value="#{registerEmployee.employee.employeeName}"></p:inputText>
		<p:outputLabel value="Enter Employee Hire Date:"></p:outputLabel>
		<p:calendar value="#{registerEmployee.employee.employeeHireDate}"></p:calendar>
		<p:outputLabel value="Enter Employee Salary:"></p:outputLabel>
		<p:inputText value="#{registerEmployee.employee.employeeSalary}"></p:inputText>
	</p:panelGrid>
	<p:commandButton value="Register" action="#{registerEmployee.register}" update="messages"></p:commandButton>
</h:form>
</html>

Employee RegisteredEmployee Persisted

Summary

This tutorial aimed to help you get both of Hibernate and EclipseLink JPA implementations used into your project. JPA has changed your life, it’s so easy to configure, use and track. It’s plugged in with a default logging mechanism that would help you find your problem shortly. Contribute us by commenting below and find downloaded source code.

本文转载自:忘记了

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