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

時間 2019-11-09

標籤 spring data jpa 教程第一部分 configuration 翻譯欄目 Spring 简体版

原文原文鏈接

Spring Data JPA項目旨在簡化基於倉庫的JPA的建立並減小與數據庫交互的所需的代碼量。本人在本身的工做和我的愛好項目中已經使用一段時間，它倒是是事情如此簡單和清洗，如今是時候與你分享個人知識。css

本文是個人Spring Data JPA教程的第一部分，將向你描述的是，當你使用Hibernate做爲你的jpa提供者時怎樣配置Spring Data JPA，在咱們開始以前，首先應該明白一件事情，本教程不是Hibernate, JPA 或 Spring的人們教程，若是你想理解在個人Spring Data JPA教程中描述的概念，你必須有關於這些技術方面的經驗html

本教程的依賴以下:java

BoneCP 0.7.1.RELEASE (一樣你也能夠採用其餘的數據源實現)
Hibernate 4.0.1.Final
Spring Framework 3.1.0.RELEASE
Spring Data JPA 1.0.2
Servlet API 3.0

固然，既然本人使用Maven做爲構建工具，若是你想運行個人example應用你必須安裝它。 mysql

開始

如今開始了. 你能夠經過以下步驟配置Spring Data JPA:git

獲取必須的依賴.
在Spring application context configuration裏面配置必須的bean. Spring Data JPA須要的bean是: 數據源, 事務管理器和實體管理工廠.
配置Spring Data JPA.

這些步驟在下面詳細解釋:github

獲取必須的依賴

首先，你須要獲取必須的依賴，你能夠經過在你的pom.xml文件裏面配置這些依賴，個人example的pom.xml以下：web

<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應用上下文

第二步，你必須配置Spring應用上下文，也許您還記得，你須要配置數據源，事務管理器和實體管理器工廠的bean。若是您正在使用Spring 3.1和Servlet 3.0，你能夠這樣作到，經過實現一個Java配置類，並在您的Web應用程序初始化的時候加載該配置類。個人應用程序上下文配置類的內容以下下：spring

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";

    @Resource
    private Environment environment;

    @Bean
    public 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;
    }

    @Bean
    public JpaTransactionManager transactionManager() throws ClassNotFoundException {
        JpaTransactionManager transactionManager = new JpaTransactionManager();

        transactionManager.setEntityManagerFactory(entityManagerFactoryBean().getObject());

        return transactionManager;
    }

    @Bean
    public 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;
    }

    @Bean
    public 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;
    }

    @Bean
    public ViewResolver viewResolver() {
        InternalResourceViewResolver viewResolver = new InternalResourceViewResolver();

        viewResolver.setViewClass(JstlView.class);
        viewResolver.setPrefix(VIEW_RESOLVER_PREFIX);
        viewResolver.setSuffix(VIEW_RESOLVER_SUFFIX);

        return viewResolver;
    }
}

個人web應用初始器以下：sql

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 = "/";
    
    @Override
    public 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來標識屬性文件的位置，屬性文件包含了使用的配置參數的值，myapplication.properties文件內容以下：數據庫

# 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，你必須配置Spring Data JPA,若是你留心，你可能已經注意到，本人在個人應用上下文配置類使用@ImportResource annotation 來從xml配置文件導入額外的配置. 當前Spring Data JPA不支持java配置，所以，惟一的方式是使用XML配置文件，個人applicationContext.xml文件以下：

<?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/beans
       http://www.springframework.org/schema/beans/spring-beans-3.1.xsd
       http://www.springframework.org/schema/data/jpa
   http://www.springframework.org/schema/data/jpa/spring-jpa-1.0.xsd
       http://www.springframework.org/schema/mvc
       http://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 resources
       are still served by the containers default servlet. Requires Spring Framework
       3.0 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

本文介紹內容：我如今已經向你演示瞭如何配置Spring Data JPA。同時也建立了一個示例應用程序來演示配置的實際運行。你能夠經過從Github獲取個人示例應用程序來測試本身的配置，並經過使用Maven Jetty plugin來運行這個示例web應用（注：請記住，首先建立模型和倉庫的package。既然不可能向Git暫存區域添加空目錄，Github倉庫也不具備它們）。