Spring JPA Data + Hibernate + MySQL + MAVEN
Development of web-applications with the help of Spring MVC implies creation of several logical layers of architecture. One of the layers is a DAO (Repository) layer. It is responsible for communication with a database. If you developed the DAO layer at least once, you should know that it involves a lot of boilerplate code. A Spring Data take a part of the routine job related to the DAO on itself.
Now we can go ahead with a java code:
package com.spr.model;
@Entity
@Table(name = "shops")
public class Shop {
@Id
@GeneratedValue
private Integer id;
private String name;
@Column(name = "employees_number")
private Integer emplNumber;
//define getter and setter method of the propery
}
In the property file concentrated all configuration data:
#DB properties:
db.driver=net.sf.log4jdbc.DriverSpy
db.url=jdbc:log4jdbc:mysql://localhost:3306/hibnatedb
db.username=hibuser
db.password=root
#Hibernate Configuration:
hibernate.dialect=org.hibernate.dialect.MySQL5InnoDBDialect
#turn off the hib,use the log4jdbc instead.
hibernate.show_sql=false
entitymanager.packages.to.scan=com.spr.model
The WebAppConfig class contains all java based configurations:
@Configuration
@EnableWebMvc
@EnableTransactionManagement
@ComponentScan("com.spr")
@PropertySource("classpath:application.properties")
@EnableJpaRepositories("com.spr.repository")
public class WebAppConfig {
private static final String PROPERTY_NAME_DATABASE_DRIVER = "db.driver";
private static final String PROPERTY_NAME_DATABASE_PASSWORD = "db.password";
private static final String PROPERTY_NAME_DATABASE_URL = "db.url";
private static final String PROPERTY_NAME_DATABASE_USERNAME = "db.username";
private static final String PROPERTY_NAME_HIBERNATE_DIALECT = "hibernate.dialect";
private static final String PROPERTY_NAME_HIBERNATE_SHOW_SQL = "hibernate.show_sql";
private static final String PROPERTY_NAME_ENTITYMANAGER_PACKAGES_TO_SCAN = "entitymanager.packages.to.scan";
@Resource
private Environment env;
@Bean
public DataSource dataSource() {
DriverManagerDataSource dataSource = new DriverManagerDataSource();
dataSource.setDriverClassName(env.getRequiredProperty(PROPERTY_NAME_DATABASE_DRIVER));
dataSource.setUrl(env.getRequiredProperty(PROPERTY_NAME_DATABASE_URL));
dataSource.setUsername(env.getRequiredProperty(PROPERTY_NAME_DATABASE_USERNAME));
dataSource.setPassword(env.getRequiredProperty(PROPERTY_NAME_DATABASE_PASSWORD));
return dataSource;
}
@Bean
public LocalContainerEntityManagerFactoryBean entityManagerFactory() {
LocalContainerEntityManagerFactoryBean entityManagerFactoryBean = new LocalContainerEntityManagerFactoryBean();
entityManagerFactoryBean.setDataSource(dataSource());
entityManagerFactoryBean.setPersistenceProviderClass(HibernatePersistence.class);
entityManagerFactoryBean.setPackagesToScan(env.getRequiredProperty(PROPERTY_NAME_ENTITYMANAGER_PACKAGES_TO_SCAN));
entityManagerFactoryBean.setJpaProperties(hibProperties());
return entityManagerFactoryBean;
}
private Properties hibProperties() {
Properties properties = new Properties();
properties.put(PROPERTY_NAME_HIBERNATE_DIALECT, env.getRequiredProperty(PROPERTY_NAME_HIBERNATE_DIALECT));
properties.put(PROPERTY_NAME_HIBERNATE_SHOW_SQL, env.getRequiredProperty(PROPERTY_NAME_HIBERNATE_SHOW_SQL));
return properties;
}
@Bean
public JpaTransactionManager transactionManager() {
JpaTransactionManager transactionManager = new JpaTransactionManager();transactionManager.setEntityManagerFactory(entityManagerFactory().getObject());
return transactionManager;
}
@Bean
public UrlBasedViewResolver setupViewResolver() {
UrlBasedViewResolver resolver = new UrlBasedViewResolver();
resolver.setPrefix("/WEB-INF/pages/");
resolver.setSuffix(".jsp");
resolver.setViewClass(JstlView.class);
return resolver;
}
@Bean
public ResourceBundleMessageSource messageSource() {
ResourceBundleMessageSource source = new ResourceBundleMessageSource();
source.setBasename(env.getRequiredProperty("message.source.basename"));
source.setUseCodeAsDefaultMessage(true);
return source;
}
}
Pay your attention at @EnableJpaRepositories annotation. It enables usage of JPA repositories. The com.spr.repository package will be scaned to detect repositories. In the entityManagerFactory bean I determined that Hibernate will be used as JPA implementation.
Initializer class will be omitted.
Definitely it is the most simplest code snippet in the tutorial. But it requires the most high attention. The JpaRepository interface contains the basic operations which can be performed with any entity (CRUD operations). More information you can find on the official documentation page.
Here is a code of the ShopService interface:
import com.spr.exception.ShopNotFound;
import com.spr.model.Shop;
public interface ShopService {
public Shop create(Shop shop);
public Shop delete(int id) throws ShopNotFound;
public List<Shop> findAll();
public Shop update(Shop shop) throws ShopNotFound;
public Shop findById(int id);
}
And the implementation of the service interface:
package com.spr.service;
import java.util.List;
import javax.annotation.Resource;
import org.springframework.stereotype.Service;
import org.springframework.transaction.annotation.Transactional;
import com.spr.exception.ShopNotFound;
import com.spr.model.Shop;
import com.spr.repository.ShopRepository;
@Service
public class ShopServiceImpl implements ShopService {
@Resource
private ShopRepository shopRepository;
@Override
@Transactional
public Shop create(Shop shop) {
Shop createdShop = shop;
return shopRepository.save(createdShop);
}
@Override
@Transactional
public Shop findById(int id) {
return shopRepository.findOne(id);
}
@Override
@Transactional(rollbackFor=ShopNotFound.class)
public Shop delete(int id) throws ShopNotFound {
Shop deletedShop = shopRepository.findOne(id);
if (deletedShop == null)
throw new ShopNotFound();
shopRepository.delete(deletedShop);
return deletedShop;
}
@Override
@Transactional
public List<Shop> findAll() {
return shopRepository.findAll();
}
@Override
@Transactional(rollbackFor=ShopNotFound.class)
public Shop update(Shop shop) throws ShopNotFound {
Shop updatedShop = shopRepository.findOne(shop.getId());
if (updatedShop == null)
throw new ShopNotFound();
updatedShop.setName(shop.getName());
updatedShop.setEmplNumber(shop.getEmplNumber());
return updatedShop;
}
}
In this way the ShopRepository is used.
package com.spr.controller;
import java.util.List;
import javax.validation.Valid;
import org.springframework.beans.factory.annotation.Autowired;
import org.springframework.stereotype.Controller;
import org.springframework.validation.BindingResult;
import org.springframework.web.bind.WebDataBinder;
import org.springframework.web.bind.annotation.InitBinder;
import org.springframework.web.bind.annotation.ModelAttribute;
import org.springframework.web.bind.annotation.PathVariable;
import org.springframework.web.bind.annotation.RequestMapping;
import org.springframework.web.bind.annotation.RequestMethod;
import org.springframework.web.servlet.ModelAndView;
import org.springframework.web.servlet.mvc.support.RedirectAttributes;
import com.spr.exception.ShopNotFound;
import com.spr.model.Shop;
import com.spr.service.ShopService;
import com.spr.validation.ShopValidator;
@Controller
@RequestMapping(value="/shop")
public class ShopController {
@Autowired
private ShopService shopService;
@Autowired
private ShopValidator shopValidator;
@InitBinder
private void initBinder(WebDataBinder binder) {
binder.setValidator(shopValidator);
}
@RequestMapping(value="/create", method=RequestMethod.GET)
public ModelAndView newShopPage() {
ModelAndView mav = new ModelAndView("shop-new", "shop", new Shop());
return mav;
}
@RequestMapping(value="/create", method=RequestMethod.POST)
public ModelAndView createNewShop(@ModelAttribute @Valid Shop shop,
BindingResult result,
final RedirectAttributes redirectAttributes) {
if (result.hasErrors())
return new ModelAndView("shop-new");
ModelAndView mav = new ModelAndView();
String message = "New shop "+shop.getName()+" was successfully created.";
shopService.create(shop);
mav.setViewName("redirect:/index.html");
redirectAttributes.addFlashAttribute("message", message);
return mav;
}
@RequestMapping(value="/list", method=RequestMethod.GET)
public ModelAndView shopListPage() {
ModelAndView mav = new ModelAndView("shop-list");
List<Shop> shopList = shopService.findAll();
mav.addObject("shopList", shopList);
return mav;
}
@RequestMapping(value="/edit/{id}", method=RequestMethod.GET)
public ModelAndView editShopPage(@PathVariable Integer id) {
ModelAndView mav = new ModelAndView("shop-edit");
Shop shop = shopService.findById(id);
mav.addObject("shop", shop);
return mav;
}
@RequestMapping(value="/edit/{id}", method=RequestMethod.POST)
public ModelAndView editShop(@ModelAttribute @Valid Shop shop,
BindingResult result,
@PathVariable Integer id,
final RedirectAttributes redirectAttributes) throws ShopNotFound {
if (result.hasErrors())
return new ModelAndView("shop-edit");
ModelAndView mav = new ModelAndView("redirect:/index.html");
String message = "Shop was successfully updated.";
shopService.update(shop);
redirectAttributes.addFlashAttribute("message", message);
return mav;
}
@RequestMapping(value="/delete/{id}", method=RequestMethod.GET)
public ModelAndView deleteShop(@PathVariable Integer id,
final RedirectAttributes redirectAttributes) throws ShopNotFound {
ModelAndView mav = new ModelAndView("redirect:/index.html");
Shop shop = shopService.delete(id);
String message = "The shop "+shop.getName()+" was successfully deleted.";
redirectAttributes.addFlashAttribute("message", message);
return mav;
}
}
Summary
The Spring Data is very powerful weapon, it helps you develop an application more faster and avoid hundreds of boilerplate strings of code. Usage of Spring Data is the most convenient way to create a DAO layer in an application.
Article Reference from http://fruzenshtein.com
Github https://github.com/Fruzenshtein/spr-data
Preparation
In the article we concentrate on the Spring Data, so all stuff which is out topic It will omit. But in the start provide a bulk of links which can be helpful for you in context of this tutorial.- Creation of dynamic web project in Eclipse with Maven.
- Simple Spring MVC application with the java based configuration.
- Spring MVC + Hibernate sample application.
CREATE TABLE `shops` ( `id` int(6) NOT NULL AUTO_INCREMENT, `name` varchar(60) NOT NULL, `employees_number` int(6) NOT NULL, PRIMARY KEY (`id`)) ENGINE=InnoDB AUTO_INCREMENT=6 DEFAULT CHARSET=utf8; |
package com.spr.model;
@Entity
@Table(name = "shops")
public class Shop {
@Id
@GeneratedValue
private Integer id;
private String name;
@Column(name = "employees_number")
private Integer emplNumber;
//define getter and setter method of the propery
}
Configuration of Spring Data
I believe that a screenshot of the project will help you to understand what’s going on.
In the property file concentrated all configuration data:
#DB properties:
db.driver=net.sf.log4jdbc.DriverSpy
db.url=jdbc:log4jdbc:mysql://localhost:3306/hibnatedb
db.username=hibuser
db.password=root
#Hibernate Configuration:
hibernate.dialect=org.hibernate.dialect.MySQL5InnoDBDialect
#turn off the hib,use the log4jdbc instead.
hibernate.show_sql=false
entitymanager.packages.to.scan=com.spr.model
The WebAppConfig class contains all java based configurations:
@Configuration
@EnableWebMvc
@EnableTransactionManagement
@ComponentScan("com.spr")
@PropertySource("classpath:application.properties")
@EnableJpaRepositories("com.spr.repository")
public class WebAppConfig {
private static final String PROPERTY_NAME_DATABASE_DRIVER = "db.driver";
private static final String PROPERTY_NAME_DATABASE_PASSWORD = "db.password";
private static final String PROPERTY_NAME_DATABASE_URL = "db.url";
private static final String PROPERTY_NAME_DATABASE_USERNAME = "db.username";
private static final String PROPERTY_NAME_HIBERNATE_DIALECT = "hibernate.dialect";
private static final String PROPERTY_NAME_HIBERNATE_SHOW_SQL = "hibernate.show_sql";
private static final String PROPERTY_NAME_ENTITYMANAGER_PACKAGES_TO_SCAN = "entitymanager.packages.to.scan";
@Resource
private Environment env;
@Bean
public DataSource dataSource() {
DriverManagerDataSource dataSource = new DriverManagerDataSource();
dataSource.setDriverClassName(env.getRequiredProperty(PROPERTY_NAME_DATABASE_DRIVER));
dataSource.setUrl(env.getRequiredProperty(PROPERTY_NAME_DATABASE_URL));
dataSource.setUsername(env.getRequiredProperty(PROPERTY_NAME_DATABASE_USERNAME));
dataSource.setPassword(env.getRequiredProperty(PROPERTY_NAME_DATABASE_PASSWORD));
return dataSource;
}
@Bean
public LocalContainerEntityManagerFactoryBean entityManagerFactory() {
LocalContainerEntityManagerFactoryBean entityManagerFactoryBean = new LocalContainerEntityManagerFactoryBean();
entityManagerFactoryBean.setDataSource(dataSource());
entityManagerFactoryBean.setPersistenceProviderClass(HibernatePersistence.class);
entityManagerFactoryBean.setPackagesToScan(env.getRequiredProperty(PROPERTY_NAME_ENTITYMANAGER_PACKAGES_TO_SCAN));
entityManagerFactoryBean.setJpaProperties(hibProperties());
return entityManagerFactoryBean;
}
private Properties hibProperties() {
Properties properties = new Properties();
properties.put(PROPERTY_NAME_HIBERNATE_DIALECT, env.getRequiredProperty(PROPERTY_NAME_HIBERNATE_DIALECT));
properties.put(PROPERTY_NAME_HIBERNATE_SHOW_SQL, env.getRequiredProperty(PROPERTY_NAME_HIBERNATE_SHOW_SQL));
return properties;
}
@Bean
public JpaTransactionManager transactionManager() {
JpaTransactionManager transactionManager = new JpaTransactionManager();transactionManager.setEntityManagerFactory(entityManagerFactory().getObject());
return transactionManager;
}
@Bean
public UrlBasedViewResolver setupViewResolver() {
UrlBasedViewResolver resolver = new UrlBasedViewResolver();
resolver.setPrefix("/WEB-INF/pages/");
resolver.setSuffix(".jsp");
resolver.setViewClass(JstlView.class);
return resolver;
}
@Bean
public ResourceBundleMessageSource messageSource() {
ResourceBundleMessageSource source = new ResourceBundleMessageSource();
source.setBasename(env.getRequiredProperty("message.source.basename"));
source.setUseCodeAsDefaultMessage(true);
return source;
}
}
Pay your attention at @EnableJpaRepositories annotation. It enables usage of JPA repositories. The com.spr.repository package will be scaned to detect repositories. In the entityManagerFactory bean I determined that Hibernate will be used as JPA implementation.
Initializer class will be omitted.
DAO & Service layers
The repository for the Shop entity:package com.spr.repository; import org.springframework.data.jpa.repository.JpaRepository;import com.spr.model.Shop;public interface ShopRepository extends JpaRepository<Shop, Integer> {} |
Here is a code of the ShopService interface:
import com.spr.exception.ShopNotFound;
import com.spr.model.Shop;
public interface ShopService {
public Shop create(Shop shop);
public Shop delete(int id) throws ShopNotFound;
public List<Shop> findAll();
public Shop update(Shop shop) throws ShopNotFound;
public Shop findById(int id);
}
And the implementation of the service interface:
package com.spr.service;
import java.util.List;
import javax.annotation.Resource;
import org.springframework.stereotype.Service;
import org.springframework.transaction.annotation.Transactional;
import com.spr.exception.ShopNotFound;
import com.spr.model.Shop;
import com.spr.repository.ShopRepository;
@Service
public class ShopServiceImpl implements ShopService {
@Resource
private ShopRepository shopRepository;
@Override
@Transactional
public Shop create(Shop shop) {
Shop createdShop = shop;
return shopRepository.save(createdShop);
}
@Override
@Transactional
public Shop findById(int id) {
return shopRepository.findOne(id);
}
@Override
@Transactional(rollbackFor=ShopNotFound.class)
public Shop delete(int id) throws ShopNotFound {
Shop deletedShop = shopRepository.findOne(id);
if (deletedShop == null)
throw new ShopNotFound();
shopRepository.delete(deletedShop);
return deletedShop;
}
@Override
@Transactional
public List<Shop> findAll() {
return shopRepository.findAll();
}
@Override
@Transactional(rollbackFor=ShopNotFound.class)
public Shop update(Shop shop) throws ShopNotFound {
Shop updatedShop = shopRepository.findOne(shop.getId());
if (updatedShop == null)
throw new ShopNotFound();
updatedShop.setName(shop.getName());
updatedShop.setEmplNumber(shop.getEmplNumber());
return updatedShop;
}
}
In this way the ShopRepository is used.
Controller
Finally I can use ShopSrviceImpl class in the controller. All JSP pages will be omitted, so you can find them source code on the GitHub.package com.spr.controller;
import java.util.List;
import javax.validation.Valid;
import org.springframework.beans.factory.annotation.Autowired;
import org.springframework.stereotype.Controller;
import org.springframework.validation.BindingResult;
import org.springframework.web.bind.WebDataBinder;
import org.springframework.web.bind.annotation.InitBinder;
import org.springframework.web.bind.annotation.ModelAttribute;
import org.springframework.web.bind.annotation.PathVariable;
import org.springframework.web.bind.annotation.RequestMapping;
import org.springframework.web.bind.annotation.RequestMethod;
import org.springframework.web.servlet.ModelAndView;
import org.springframework.web.servlet.mvc.support.RedirectAttributes;
import com.spr.exception.ShopNotFound;
import com.spr.model.Shop;
import com.spr.service.ShopService;
import com.spr.validation.ShopValidator;
@Controller
@RequestMapping(value="/shop")
public class ShopController {
@Autowired
private ShopService shopService;
@Autowired
private ShopValidator shopValidator;
@InitBinder
private void initBinder(WebDataBinder binder) {
binder.setValidator(shopValidator);
}
@RequestMapping(value="/create", method=RequestMethod.GET)
public ModelAndView newShopPage() {
ModelAndView mav = new ModelAndView("shop-new", "shop", new Shop());
return mav;
}
@RequestMapping(value="/create", method=RequestMethod.POST)
public ModelAndView createNewShop(@ModelAttribute @Valid Shop shop,
BindingResult result,
final RedirectAttributes redirectAttributes) {
if (result.hasErrors())
return new ModelAndView("shop-new");
ModelAndView mav = new ModelAndView();
String message = "New shop "+shop.getName()+" was successfully created.";
shopService.create(shop);
mav.setViewName("redirect:/index.html");
redirectAttributes.addFlashAttribute("message", message);
return mav;
}
@RequestMapping(value="/list", method=RequestMethod.GET)
public ModelAndView shopListPage() {
ModelAndView mav = new ModelAndView("shop-list");
List<Shop> shopList = shopService.findAll();
mav.addObject("shopList", shopList);
return mav;
}
@RequestMapping(value="/edit/{id}", method=RequestMethod.GET)
public ModelAndView editShopPage(@PathVariable Integer id) {
ModelAndView mav = new ModelAndView("shop-edit");
Shop shop = shopService.findById(id);
mav.addObject("shop", shop);
return mav;
}
@RequestMapping(value="/edit/{id}", method=RequestMethod.POST)
public ModelAndView editShop(@ModelAttribute @Valid Shop shop,
BindingResult result,
@PathVariable Integer id,
final RedirectAttributes redirectAttributes) throws ShopNotFound {
if (result.hasErrors())
return new ModelAndView("shop-edit");
ModelAndView mav = new ModelAndView("redirect:/index.html");
String message = "Shop was successfully updated.";
shopService.update(shop);
redirectAttributes.addFlashAttribute("message", message);
return mav;
}
@RequestMapping(value="/delete/{id}", method=RequestMethod.GET)
public ModelAndView deleteShop(@PathVariable Integer id,
final RedirectAttributes redirectAttributes) throws ShopNotFound {
ModelAndView mav = new ModelAndView("redirect:/index.html");
Shop shop = shopService.delete(id);
String message = "The shop "+shop.getName()+" was successfully deleted.";
redirectAttributes.addFlashAttribute("message", message);
return mav;
}
}
Summary
The Spring Data is very powerful weapon, it helps you develop an application more faster and avoid hundreds of boilerplate strings of code. Usage of Spring Data is the most convenient way to create a DAO layer in an application.
Article Reference from http://fruzenshtein.com
Github https://github.com/Fruzenshtein/spr-data
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