Spring Data JPA教程，第一部分: Configuration（翻译）

Spring Data JPA项目旨在简化基于仓库的JPA的创建并减少与数据库交互的所需的代码量。本人在自己的工作和个人爱好项目中已经使用一段时间，它却是是事情如此简单和清洗，现在是时候与你分享我的知识。

本文是我的Spring Data JPA教程的第一部分，将向你描述的是，当你使用Hibernate作为你的jpa提供者时怎样配置Spring Data JPA，在我们开始之前，首先应该明白一件事情，本教程不是Hibernate, JPA 或 Spring的人们教程，如果你想理解在我的Spring Data JPA教程中描述的概念，你必须有关于这些技术方面的经验

本教程的依赖如下:

BoneCP 0.7.1.RELEASE (同样你也可以采用其他的数据源实现)
Hibernate 4.0.1.Final
Spring Framework 3.1.0.RELEASE
Spring Data JPA 1.0.2
Servlet API 3.0

当然，既然本人使用Maven作为构建工具，如果你想运行我的example应用你必须安装它。

开始

现在开始了. 你可以通过如下步骤配置Spring Data JPA:

获取必须的依赖.
在Spring application context configuration里面配置必须的bean. Spring Data JPA需要的bean是: 数据源, 事务管理器和实体管理工厂.
配置Spring Data JPA.

这些步骤在下面详细解释:

获取必须的依赖

首先，你需要获取必须的依赖，你可以通过在你的pom.xml文件里面配置这些依赖，我的example的pom.xml如下：

<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>net.petrikainulainen.spring</groupId><artifactId>data-jpa-tutorial-part-one</artifactId><packaging>war</packaging><version>0.1</version><name>Spring Data JPA Tutorial Part One</name><description>Spring Data JPA Tutorial Part One</description><licenses><license><name>Apache License 2.0</name><url>http://www.apache.org/licenses/LICENSE-2.0</url></license></licenses><url>http://www.petrikainulainen.net</url><repositories><repository><id>repository.jboss.org-public</id><name>JBoss repository</name><url>https://repository.jboss.org/nexus/content/groups/public</url></repository></repositories><properties><hibernate.version>4.0.1.Final</hibernate.version><mysql.connector.version>5.1.18</mysql.connector.version><slf4j.version>1.6.1</slf4j.version><spring.version>3.1.0.RELEASE</spring.version><project.build.sourceEncoding>UTF-8</project.build.sourceEncoding></properties><dependencies><!-- Spring Framework --><dependency><groupId>org.springframework</groupId><artifactId>spring-beans</artifactId><version>${spring.version}</version></dependency><dependency><groupId>org.springframework</groupId><artifactId>spring-core</artifactId><version>${spring.version}</version></dependency><dependency><groupId>org.springframework</groupId><artifactId>spring-context-support</artifactId><version>${spring.version}</version></dependency><dependency><groupId>org.springframework</groupId><artifactId>spring-context</artifactId><version>${spring.version}</version></dependency><dependency><groupId>org.springframework</groupId><artifactId>spring-jdbc</artifactId><version>${spring.version}</version></dependency><dependency><groupId>org.springframework</groupId><artifactId>spring-orm</artifactId><version>${spring.version}</version></dependency><dependency><groupId>org.springframework</groupId><artifactId>spring-tx</artifactId><version>${spring.version}</version></dependency><!-- Spring MVC --><dependency><groupId>org.springframework</groupId><artifactId>spring-web</artifactId><version>${spring.version}</version></dependency><dependency><groupId>org.springframework</groupId><artifactId>spring-webmvc</artifactId><version>${spring.version}</version></dependency><dependency><groupId>cglib</groupId><artifactId>cglib</artifactId><version>2.2.2</version></dependency><!-- Spring Data JPA --><dependency><groupId>org.springframework.data</groupId><artifactId>spring-data-jpa</artifactId><version>1.0.2.RELEASE</version></dependency><!-- Hibernate --><dependency><groupId>org.hibernate</groupId><artifactId>hibernate-core</artifactId><version>${hibernate.version}</version></dependency><dependency><groupId>org.hibernate</groupId><artifactId>hibernate-entitymanager</artifactId><version>${hibernate.version}</version></dependency><!-- H2 Database --><dependency><groupId>com.h2database</groupId><artifactId>h2</artifactId><version>1.3.160</version></dependency><!-- MySQL JDBC connector --><!-- If you want to use MySQL, uncomment this dependency declation. --><!--<dependency><groupId>mysql</groupId><artifactId>mysql-connector-java</artifactId><version>${mysql.connector.version}</version></dependency>--><!-- PostgreSQL JDBC 4 --><!-- If you don't want to use PostgreSQL, uncomment this dependency declaration. --><!--<dependency><groupId>postgresql</groupId><artifactId>postgresql</artifactId><version>9.0-801.jdbc4</version></dependency>--><!-- BoneCP --><dependency><groupId>com.jolbox</groupId><artifactId>bonecp</artifactId><version>0.7.1.RELEASE</version></dependency><!-- Servlet API 3.0 --><dependency><groupId>javax.servlet</groupId><artifactId>javax.servlet-api</artifactId><version>3.0.1</version><scope>provided</scope></dependency><dependency><groupId>javax.servlet</groupId><artifactId>jstl</artifactId><version>1.2</version></dependency><!-- Logging dependencies --><dependency><groupId>org.slf4j</groupId><artifactId>slf4j-api</artifactId><version>${slf4j.version}</version></dependency><dependency><groupId>org.slf4j</groupId><artifactId>slf4j-log4j12</artifactId><version>${slf4j.version}</version></dependency><dependency><groupId>log4j</groupId><artifactId>log4j</artifactId><version>1.2.16</version></dependency><!-- Testing Dependencies --><dependency><groupId>junit</groupId><artifactId>junit</artifactId><version>4.9</version><scope>test</scope></dependency></dependencies><build><finalName>data-jpa-tutorial-part-one</finalName><plugins><plugin><groupId>org.apache.maven.plugins</groupId><artifactId>maven-compiler-plugin</artifactId><version>2.3.2</version><configuration><source>1.6</source><target>1.6</target></configuration></plugin><plugin><groupId>org.apache.maven.plugins</groupId><artifactId>maven-war-plugin</artifactId><version>2.1.1</version><configuration><failOnMissingWebXml>false</failOnMissingWebXml></configuration></plugin><plugin><groupId>org.mortbay.jetty</groupId><artifactId>jetty-maven-plugin</artifactId><version>8.1.0.RC2</version><configuration><scanIntervalSeconds>0</scanIntervalSeconds><webAppConfig><defaultsDescriptor>src/main/resources/webdefault.xml</defaultsDescriptor></webAppConfig></configuration></plugin><plugin><groupId>org.apache.maven.plugins</groupId><artifactId>maven-site-plugin</artifactId><version>3.0</version><configuration><reportPlugins><!-- Cobertura Plugin --><plugin><groupId>org.codehaus.mojo</groupId><artifactId>cobertura-maven-plugin</artifactId><version>2.5.1</version></plugin></reportPlugins></configuration></plugin></plugins></build>
</project>

配置 Spring应用上下文

第二步，你必须配置Spring应用上下文，也许您还记得，你需要配置数据源，事务管理器和实体管理器工厂的bean。如果您正在使用Spring 3.1和Servlet 3.0，你可以这样做到，通过实现一个Java配置类，并在您的Web应用程序初始化的时候加载该配置类。我的应用程序上下文配置类的内容如下下：

import com.jolbox.bonecp.BoneCPDataSource;
import org.hibernate.ejb.HibernatePersistence;
import org.springframework.context.MessageSource;
import org.springframework.context.annotation.*;
import org.springframework.context.support.ResourceBundleMessageSource;
import org.springframework.core.env.Environment;
import org.springframework.orm.jpa.JpaTransactionManager;
import org.springframework.orm.jpa.LocalContainerEntityManagerFactoryBean;
import org.springframework.web.servlet.ViewResolver;
import org.springframework.web.servlet.config.annotation.EnableWebMvc;
import org.springframework.web.servlet.view.InternalResourceViewResolver;
import org.springframework.web.servlet.view.JstlView;import javax.annotation.Resource;
import javax.sql.DataSource;/*** An application context Java configuration class. The usage of Java configuration* requires Spring Framework 3.0 or higher with following exceptions:* <ul>*     <li>@EnableWebMvc annotation requires Spring Framework 3.1</li>* </ul>* @author Petri Kainulainen*/
@Configuration
@ComponentScan(basePackages = {"net.petrikainulainen.spring.datajpa.controller"})
@EnableWebMvc
@ImportResource("classpath:applicationContext.xml")
@PropertySource("classpath:application.properties")
public class ApplicationContext {private static final String VIEW_RESOLVER_PREFIX = "/WEB-INF/jsp/";private static final String VIEW_RESOLVER_SUFFIX = ".jsp";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_FORMAT_SQL = "hibernate.format_sql";private static final String PROPERTY_NAME_HIBERNATE_NAMING_STRATEGY = "hibernate.ejb.naming_strategy";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";private static final String PROPERTY_NAME_MESSAGESOURCE_BASENAME = "message.source.basename";private static final String PROPERTY_NAME_MESSAGESOURCE_USE_CODE_AS_DEFAULT_MESSAGE = "message.source.use.code.as.default.message";@Resourceprivate Environment environment;@Beanpublic DataSource dataSource() {BoneCPDataSource dataSource = new BoneCPDataSource();dataSource.setDriverClass(environment.getRequiredProperty(PROPERTY_NAME_DATABASE_DRIVER));dataSource.setJdbcUrl(environment.getRequiredProperty(PROPERTY_NAME_DATABASE_URL));dataSource.setUsername(environment.getRequiredProperty(PROPERTY_NAME_DATABASE_USERNAME));dataSource.setPassword(environment.getRequiredProperty(PROPERTY_NAME_DATABASE_PASSWORD));return dataSource;}@Beanpublic JpaTransactionManager transactionManager() throws ClassNotFoundException {JpaTransactionManager transactionManager = new JpaTransactionManager();transactionManager.setEntityManagerFactory(entityManagerFactoryBean().getObject());return transactionManager;}@Beanpublic LocalContainerEntityManagerFactoryBean entityManagerFactoryBean() throws ClassNotFoundException {LocalContainerEntityManagerFactoryBean entityManagerFactoryBean = new LocalContainerEntityManagerFactoryBean();entityManagerFactoryBean.setDataSource(dataSource());entityManagerFactoryBean.setPackagesToScan(environment.getRequiredProperty(PROPERTY_NAME_ENTITYMANAGER_PACKAGES_TO_SCAN));entityManagerFactoryBean.setPersistenceProviderClass(HibernatePersistence.class);Properties jpaProterties = new Properties();jpaProterties.put(PROPERTY_NAME_HIBERNATE_DIALECT, environment.getRequiredProperty(PROPERTY_NAME_HIBERNATE_DIALECT));jpaProterties.put(PROPERTY_NAME_HIBERNATE_FORMAT_SQL, environment.getRequiredProperty(PROPERTY_NAME_HIBERNATE_FORMAT_SQL));jpaProterties.put(PROPERTY_NAME_HIBERNATE_NAMING_STRATEGY, environment.getRequiredProperty(PROPERTY_NAME_HIBERNATE_NAMING_STRATEGY));jpaProterties.put(PROPERTY_NAME_HIBERNATE_SHOW_SQL, environment.getRequiredProperty(PROPERTY_NAME_HIBERNATE_SHOW_SQL));entityManagerFactoryBean.setJpaProperties(jpaProterties);return entityManagerFactoryBean;}@Beanpublic MessageSource messageSource() {ResourceBundleMessageSource messageSource = new ResourceBundleMessageSource();messageSource.setBasename(environment.getRequiredProperty(PROPERTY_NAME_MESSAGESOURCE_BASENAME));messageSource.setUseCodeAsDefaultMessage(Boolean.parseBoolean(environment.getRequiredProperty(PROPERTY_NAME_MESSAGESOURCE_USE_CODE_AS_DEFAULT_MESSAGE)));return messageSource;}@Beanpublic ViewResolver viewResolver() {InternalResourceViewResolver viewResolver = new InternalResourceViewResolver();viewResolver.setViewClass(JstlView.class);viewResolver.setPrefix(VIEW_RESOLVER_PREFIX);viewResolver.setSuffix(VIEW_RESOLVER_SUFFIX);return viewResolver;}
}

我的web应用初始器如下：

import org.springframework.web.WebApplicationInitializer;
import org.springframework.web.context.ContextLoaderListener;
import org.springframework.web.context.support.AnnotationConfigWebApplicationContext;
import org.springframework.web.servlet.DispatcherServlet;import javax.servlet.*;/*** Web application Java configuration class. The usage of web application* initializer requires Spring Framework 3.1 and Servlet 3.0.* @author Petri Kainulainen*/
public class DataJPAExampleInitializer implements WebApplicationInitializer {private static final String DISPATCHER_SERVLET_NAME = "dispatcher";private static final String DISPATCHER_SERVLET_MAPPING = "/";@Overridepublic void onStartup(ServletContext servletContext) throws ServletException {AnnotationConfigWebApplicationContext rootContext = new AnnotationConfigWebApplicationContext();rootContext.register(ApplicationContext.class);ServletRegistration.Dynamic dispatcher = servletContext.addServlet(DISPATCHER_SERVLET_NAME, new DispatcherServlet(rootContext));dispatcher.setLoadOnStartup(1);dispatcher.addMapping(DISPATCHER_SERVLET_MAPPING);servletContext.addListener(new ContextLoaderListener(rootContext));}
}

你可能注意到，本人使用@PropertySource annotation来标识属性文件的位置，属性文件包含了使用的配置参数的值，myapplication.properties文件内容如下：

# The default database is H2 memory database but I have also
# added configuration needed to use either MySQL and PostgreSQL.#Database Configuration
db.driver=org.h2.Driver
#db.driver=com.mysql.jdbc.Driver
#db.driver=org.postgresql.Driver
db.url=jdbc:h2:mem:datajpa
#db.url=jdbc:mysql://localhost:3306/datajpa
#db.url=jdbc:postgresql://localhost/datajpa
db.username=sa
db.password=#Hibernate Configuration
hibernate.dialect=org.hibernate.dialect.H2Dialect
#hibernate.dialect=org.hibernate.dialect.MySQL5InnoDBDialect
#hibernate.dialect=org.hibernate.dialect.PostgreSQLDialect
hibernate.format_sql=true
hibernate.ejb.naming_strategy=org.hibernate.cfg.ImprovedNamingStrategy
hibernate.show_sql=true#MessageSource
message.source.basename=i18n/messages
message.source.use.code.as.default.message=true#EntityManager
#Declares the base package of the entity classes
entitymanager.packages.to.scan=net.petrikainulainen.spring.datajpa.model

配置Spring Data JPA

第三步，你必须配置Spring Data JPA,如果你留心，你可能已经注意到，本人在我的应用上下文配置类使用@ImportResource annotation 来从xml配置文件导入额外的配置. 当前Spring Data JPA不支持java配置，因此，唯一的方式是使用XML配置文件，我的applicationContext.xml文件如下：

<?xml version="1.0" encoding="UTF-8"?>
<beans xmlns="http://www.springframework.org/schema/beans"xmlns:jpa="http://www.springframework.org/schema/data/jpa"xmlns:mvc="http://www.springframework.org/schema/mvc"xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"xsi:schemaLocation="http://www.springframework.org/schema/beanshttp://www.springframework.org/schema/beans/spring-beans-3.1.xsdhttp://www.springframework.org/schema/data/jpahttp://www.springframework.org/schema/data/jpa/spring-jpa-1.0.xsdhttp://www.springframework.org/schema/mvchttp://www.springframework.org/schema/mvc/spring-mvc-3.1.xsd"><!--Configures the location of static resources such as css files.Requires Spring Framework 3.0 or higher.--><mvc:resources mapping="/static/**" location="/static/"/><!--Ensures that dispatcher servlet can be mapped to '/' and static resourcesare still served by the containers default servlet. Requires Spring Framework3.0 or higher.--><mvc:default-servlet-handler/><!--Configures Spring Data JPA and sets the base package of my DAOs.--><jpa:repositories base-package="net.petrikainulainen.spring.datajpa.repository"/>
</beans>

You Are Done

本文介绍内容：我现在已经向你演示了如何配置Spring Data JPA。同时也创建了一个示例应用程序来演示配置的实际运行。你可以通过从Github获取我的示例应用程序来测试自己的配置，并通过使用Maven Jetty plugin来运行这个示例web应用（注：请记住，首先创建模型和仓库的package。既然不可能向Git暂存区域添加空目录，Github仓库也不具有它们）。

我的Spring Data JPA教程的第二部分介绍了如何通过使用Spring Data JPA创建一个简单的CRUD Web应用程序。敬请关注。

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本系列Spring Data JPA 教程翻译系本人原创

作者博客园刺猬的温驯

本文链接 http://www.cnblogs.com/chenying99/archive/2013/06/19/3143516.html

本文版权归作者所有，未经作者同意，严禁转载及用作商业传播，否则将追究法律责任。

转载于:https://www.cnblogs.com/chenying99/p/3143516.html