Spring Data JPA初使用

左手的ㄟ右手 2022-08-13 12:34 172阅读 0赞

我们都知道Spring是一个非常优秀的JavaEE整合框架，它尽可能的减少我们开发的工作量和难度。

在持久层的业务逻辑方面，Spring开源组织又给我们带来了同样优秀的Spring Data JPA。

通常我们写持久层，都是先写一个接口，再写接口对应的实现类，在实现类中进行持久层的业务逻辑处理。

而现在，Spring Data JPA帮助我们自动完成了持久层的业务逻辑处理，我们要做的，仅仅是声明一个持久层接口。

**1、下载开发所需要的发布包。**

1）spring-framework-3.1.2.RELEASE-with-docs.zip

下载地址：[http://www.springsource.org/spring-framework][http_www.springsource.org_spring-framework]

2）hibernate-release-4.1.6.Final.zip

下载地址：[http://olex.openlogic.com/packages/hibernate][http_olex.openlogic.com_packages_hibernate]

3）Spring Data JPA

Spring Data JPA

下载地址：[http://www.springsource.org/spring-data/jpa][http_www.springsource.org_spring-data_jpa]

Spring Data Commons

下载地址：[http://www.springsource.org/spring-data/commons][http_www.springsource.org_spring-data_commons]

4）其他一些依赖包可以从 [http://ebr.springsource.com/repository/app/library][http_ebr.springsource.com_repository_app_library] 上查找下载

**　2、新建一个Web项目 spring-data-jpa，把相应的jar包放到/WebRoot/WEB-INF/lib目录下。**

我也没有挑选哪些是不需要的，最后用到的jar如下：

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antlr-2.7.7.jar
    com.springsource.net.sf.cglib-2.2.0.jar
    com.springsource.org.aopalliance-1.0.0.jar
    com.springsource.org.apache.commons.logging-1.1.1.jar
    com.springsource.org.aspectj.weaver-1.6.3.RELEASE.jar
    commons-lang3-3.1.jar
    dom4j-1.6.1.jar
    hibernate-commons-annotations-4.0.1.Final.jar
    hibernate-core-4.1.6.Final.jar
    hibernate-entitymanager-4.1.6.Final.jar
    hibernate-jpa-2.0-api-1.0.1.Final.jar
    javassist-3.15.0-GA.jar
    jboss-logging-3.1.0.GA.jar
    jboss-transaction-api_1.1_spec-1.0.0.Final.jar
    log4j-1.2.17.jar
    mysql-connector-java-5.0.4-bin.jar
    org.springframework.aop-3.1.2.RELEASE.jar
    org.springframework.asm-3.1.2.RELEASE.jar
    org.springframework.aspects-3.1.2.RELEASE.jar
    org.springframework.beans-3.1.2.RELEASE.jar
    org.springframework.context-3.1.2.RELEASE.jar
    org.springframework.context.support-3.1.2.RELEASE.jar
    org.springframework.core-3.1.2.RELEASE.jar
    org.springframework.expression-3.1.2.RELEASE.jar
    org.springframework.instrument-3.1.2.RELEASE.jar
    org.springframework.instrument.tomcat-3.1.2.RELEASE.jar
    org.springframework.jdbc-3.1.2.RELEASE.jar
    org.springframework.jms-3.1.2.RELEASE.jar
    org.springframework.js.resources-2.3.0.RELEASE.jar
    org.springframework.orm-3.1.2.RELEASE.jar
    org.springframework.oxm-3.1.2.RELEASE.jar
    org.springframework.test-3.1.2.RELEASE.jar
    org.springframework.transaction-3.1.2.RELEASE.jar
    org.springframework.web-3.1.2.RELEASE.jar
    org.springframework.web.portlet-3.1.2.RELEASE.jar
    org.springframework.web.servlet-3.1.2.RELEASE.jar
    slf4j-api-1.6.6.jar
    slf4j-log4j12-1.6.6.jar
    spring-data-commons-core-1.3.0.M1.jar
    spring-data-jpa-1.0.2.RELEASE.jar

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**3、在MySql数据库中建立一个叫spring\_data\_jpa的数据库。**

create database spring_data_jpa default character set utf8;

**4、JPA配置文件persistence.xml**

1）在src目录下建立一个叫META-INF的文件夹

2）在META-INF文件夹下建立persistence.xml文件

persistence.xml内容如下：

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<?xml version="1.0" encoding="UTF-8"?>
    <persistence version="2.0" 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_2_0.xsd">
                
        <persistence-unit name="myJPA" transaction-type="RESOURCE_LOCAL">
        <provider>org.hibernate.ejb.HibernatePersistence</provider>  
            <properties>
                
                <property name="hibernate.dialect" value="org.hibernate.dialect.MySQL5Dialect" />
                
                <property name="hibernate.connection.driver_class" value="com.mysql.jdbc.Driver" />
                
                <property name="hibernate.connection.username" value="root" />
                
                <property name="hibernate.connection.password" value="root" />
                
                <property name="hibernate.connection.url" value="jdbc:mysql://localhost:3306/spring_data_jpa?useUnicode=true&characterEncoding=UTF-8" />
                
                <property name="hibernate.max_fetch_depth" value="3" />
                
                <property name="hibernate.hbm2ddl.auto" value="update" />    
                <property name="hibernate.show_sql" value="true" />
                <property name="hibernate.format_sql" value="true" />
                <property name="javax.persistence.validation.mode" value="none"/>
            </properties>
        </persistence-unit>
                
    </persistence>

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**5、Spring配置文件applicationContext.xml**

在src目录下建立applicationContext.xml

applicationContext.xml内容如下：

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<?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:context="http://www.springframework.org/schema/context"  
        xmlns:aop="http://www.springframework.org/schema/aop"  
        xmlns:tx="http://www.springframework.org/schema/tx"  
        xmlns:p="http://www.springframework.org/schema/p"  
        xmlns:cache="http://www.springframework.org/schema/cache"  
        xmlns:jpa="http://www.springframework.org/schema/data/jpa"
        
        xsi:schemaLocation="http://www.springframework.org/schema/beans   
              http://www.springframework.org/schema/beans/spring-beans-3.1.xsd   
              http://www.springframework.org/schema/context   
              http://www.springframework.org/schema/context/spring-context-3.1.xsd   
              http://www.springframework.org/schema/aop   
              http://www.springframework.org/schema/aop/spring-aop-3.1.xsd   
              http://www.springframework.org/schema/tx    
              http://www.springframework.org/schema/tx/spring-tx-3.1.xsd
              http://www.springframework.org/schema/cache 
              http://www.springframework.org/schema/cache/spring-cache-3.1.xsd
              http://www.springframework.org/schema/data/jpa
              http://www.springframework.org/schema/data/jpa/spring-jpa.xsd">  
            
            <context:annotation-config />  
            
            <context:component-scan base-package="cn.luxh.app"/>
           
            
            <bean id="entityManagerFactory" class="org.springframework.orm.jpa.LocalContainerEntityManagerFactoryBean">  
                 <property name="persistenceUnitName" value="myJPA"/>
            </bean>
             
               
               <bean id="transactionManager" class="org.springframework.orm.jpa.JpaTransactionManager">  
                <property name="entityManagerFactory" ref="entityManagerFactory" />  
               </bean> 
           
               
               <tx:annotation-driven transaction-manager="transactionManager"/> 
               
                
               <jpa:repositories base-package="cn.luxh.app.repository"/>
    
            
           
    </beans>

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**6、web.xml**

web.xml内容如下：

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<?xml version="1.0" encoding="UTF-8"?>
    <web-app version="2.5" 
        xmlns="http://java.sun.com/xml/ns/javaee" 
        xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance" 
        xsi:schemaLocation="http://java.sun.com/xml/ns/javaee 
        http://java.sun.com/xml/ns/javaee/web-app_2_5.xsd">
      <display-name></display-name>    
      
       
      <context-param>
        <param-name>webAppRootKey</param-name>
        <param-value>springdatajpa.root</param-value>
      </context-param>
      <context-param>
        <param-name>log4jConfigLocation</param-name>
        <param-value>classpath:log4j.properties</param-value>
      </context-param>
      <listener>
        <listener-class>org.springframework.web.util.Log4jConfigListener</listener-class>
      </listener>
      
      
      <filter>
        <filter-name>characterEncodingFilter</filter-name>
        <filter-class>org.springframework.web.filter.CharacterEncodingFilter</filter-class>
        <init-param>
              <param-name>encoding</param-name>
              <param-value>UTF-8</param-value>
        </init-param>
        
        
      </filter>
      <filter-mapping>
        <filter-name>characterEncodingFilter</filter-name>
        <url-pattern>/*</url-pattern>
      </filter-mapping>
      
      
      <context-param>
        <param-name>contextConfigLocation</param-name>
        <param-value>classpath:applicationContext.xml</param-value>
      </context-param>
      <listener>
        <listener-class>org.springframework.web.context.ContextLoaderListener</listener-class>
      </listener>
      
      
      <listener>  
          <listener-class>org.springframework.web.util.IntrospectorCleanupListener</listener-class>  
      </listener> 
      
      <welcome-file-list>
        <welcome-file>index.jsp</welcome-file>
      </welcome-file-list>
    </web-app>

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**　7、日志配置**

在src目录下建立log4j.properties文件

log4j.properties内容如下：

![复制代码][copycode.gif]

log4j.rootLogger=INFO,CONSOLE,FILE
    log4j.addivity.org.apache=true 
    # 应用于控制台 
    log4j.appender.CONSOLE=org.apache.log4j.ConsoleAppender 
    log4j.appender.Threshold=INFO 
    log4j.appender.CONSOLE.Target=System.out 
    log4j.appender.CONSOLE.layout=org.apache.log4j.PatternLayout 
    log4j.appender.CONSOLE.layout.ConversionPattern=[framework] %d - %c -%-4r [%t] %-5p %c %x - %m%n 
    #log4j.appender.CONSOLE.layout.ConversionPattern=[start]%d{DATE}[DATE]%n%p[PRIORITY]%n%x[NDC]%n%t[THREAD] n%c[CATEGORY]%n%m[MESSAGE]%n%n 
    #应用于文件 
    log4j.appender.FILE=org.apache.log4j.DailyRollingFileAppender
    log4j.appender.FILE.File=${springdatajpa.root}/springdatajpa.log 
    log4j.appender.FILE.Append=true 
    log4j.appender.FILE.layout=org.apache.log4j.PatternLayout 
    log4j.appender.FILE.layout.ConversionPattern=[framework] %d - %c -%-4r [%t] %-5p %c %x - %m%n

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**8、所有环境配完毕，开始写一个Spring Data JPA 的增删改查**

1）建立相应的包

![2012083116291850.jpg][]

2）领域模型实体类User

![复制代码][copycode.gif]

package cn.luxh.app.domain;
    
    import javax.persistence.Entity;
    import javax.persistence.GeneratedValue;
    import javax.persistence.Id;
    import javax.persistence.Table;
    
    /**
     * 用户信息
     * @author Luxh
     * 2012-8-30
     */
    @Entity
    @Table(name="t_user")
    public class User {
        
        @Id
        @GeneratedValue
        private Integer id;
        
        //账号
        private String account;
        
        //姓名
        private String name;
        
        //密码
        private String password;
        
        
        //省略 getter和setter方法
    
    }

![复制代码][copycode.gif]

3）声明持久层接口UserRepository

让UserRepository接口继承CrudRepository<T,ID>，T是领域实体，ID是领域实体的主键类型。CrudRepository实现了相应的增删改查方法。

![复制代码][copycode.gif]

package cn.luxh.app.repository;
    
    
    import org.springframework.data.repository.CrudRepository;
    
    import cn.luxh.app.domain.User;
    
    /**
     * 用户持久层接口
     * @author Luxh
     * 2012-8-31
     */
    public interface UserRepository extends CrudRepository<User,Integer>{
        
        
    }

![复制代码][copycode.gif]

不再需要持久层接口实现类。

4）业务层

一般多层架构是控制层调用业务层，业务层再调用持久层。所以这里写个业务层。

a、业务层接口：

![复制代码][copycode.gif]

package cn.luxh.app.service;
    
    import cn.luxh.app.domain.User;
    
    /**
     * 用户业务接口
     * @author Luxh
     * 2012-8-31
     */
    public interface UserService {
        
        /**
         * 保存用户
         * @param user
         */
        void saveUser(User user);
        
        /**
         * 根据id查找用户
         * @param id
         * @return
         */
        User findUserById(Integer id);
        
        /**
         * 更新用户
         * @param user
         */
        void updateUser(User user);
        
        /**
         * 根据ID删除用户
         * @param id
         */
        void deleteUserById(Integer id);
        
        
    }

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b、业务层接口实现类

![复制代码][copycode.gif]

package cn.luxh.app.service;
    
    import org.springframework.beans.factory.annotation.Autowired;
    import org.springframework.stereotype.Service;
    import org.springframework.transaction.annotation.Transactional;
    
    import cn.luxh.app.domain.User;
    import cn.luxh.app.repository.UserRepository;
    
    /**
     * 用户业务服务实现类
     * @author Luxh
     * 2012-8-31
     */
    @Service("userService")
    public class UserServiceImpl implements UserService{
        
        
        @Autowired
        private UserRepository userRepository;//注入UserRepository
    
        @Override
        @Transactional
        public void saveUser(User user) {
            userRepository.save(user);
            
        }
    
        @Override
        @Transactional(readOnly=true)
        public User findUserById(Integer id) {
            return userRepository.findOne(id);
        }
    
        
        @Override
        @Transactional
        public void updateUser(User user) {
            userRepository.save(user);
        }
    
        @Override
        @Transactional
        public void deleteUserById(Integer id) {
            userRepository.delete(id);
        }
    
    }

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**9）编写测试用例**

在执行测试的时候，发现如下错误：

![复制代码][copycode.gif]

Caused by: java.lang.NoSuchMethodError: javax.persistence.spi.PersistenceUnitInfo.getValidationMode()Ljavax/persistence/ValidationMode;
        at org.hibernate.ejb.Ejb3Configuration.configure(Ejb3Configuration.java:633)
        at org.hibernate.ejb.HibernatePersistence.createContainerEntityManagerFactory(HibernatePersistence.java:73)
        at org.springframework.orm.jpa.LocalContainerEntityManagerFactoryBean.createNativeEntityManagerFactory(LocalContainerEntityManagerFactoryBean.java:268)
        at org.springframework.orm.jpa.AbstractEntityManagerFactoryBean.afterPropertiesSet(AbstractEntityManagerFactoryBean.java:310)
        at org.springframework.beans.factory.support.AbstractAutowireCapableBeanFactory.invokeInitMethods(AbstractAutowireCapableBeanFactory.java:1514)
        at org.springframework.beans.factory.support.AbstractAutowireCapableBeanFactory.initializeBean(AbstractAutowireCapableBeanFactory.java:1452)
        ... 51 more

![复制代码][copycode.gif]

网上说是新版本的Hibernate跟javaee.jar里面的JPA接口冲突了。

解决方法：移除MyEclipse自带的Java EE 5 Libraries，自己新建一个user libraries，加入Java EE中的jsf-api.jar、jsf-impl.jar和jstl-1.2.jar，再加入Tomcat中自带的　　　　　servlet-api.jar

![2012083117222672.jpg][]

![2012083117225758.jpg][]

![2012083117233289.jpg][]

用servlet-api.jar替换掉javaee.jar就没问题了。

测试代码：

![复制代码][copycode.gif]

package cn.luxh.app.test;
    
    import org.junit.Assert;
    import org.junit.Test;
    import org.junit.runner.RunWith;
    import org.springframework.beans.factory.annotation.Autowired;
    import org.springframework.test.context.ContextConfiguration;
    import org.springframework.test.context.junit4.SpringJUnit4ClassRunner;
    
    import cn.luxh.app.domain.User;
    import cn.luxh.app.service.UserService;
    
    @RunWith(SpringJUnit4ClassRunner.class)
    @ContextConfiguration({
        "/applicationContext.xml"}) 
    public class UserTest {
        
        @Autowired
        private UserService userService;
        
        //保存用户
        @Test
        public void testSaveUser() {
            User user = new User();
            user.setAccount("LiHuai");
            user.setName("李坏");
            user.setPassword("123456");
            
            userService.saveUser(user);
        }
        
        
        //根据id查找用户
        @Test
        public void testFindUserById() {
            Integer id = 1;
            User user = userService.findUserById(id);
            Assert.assertEquals("李坏",user.getName());
        }
        
        //更新用户
        @Test
        public void testUpdateUser() {
            Integer id = 1;
            User user = userService.findUserById(id);
            user.setName("李寻欢");
            
            userService.updateUser(user);
            
        }
        
        //根据id删除用户
        @Test
        public void testDeleteUserById() {
            Integer id = 1;
            
            userService.deleteUserById(id);
        }
    
    }

![复制代码][copycode.gif]

--------------------

使用Spring Data JPA相当的简单，我们只需要定义持久层的接口，不需要编写实现代码。

步骤和注意点：

1）在spring配置文件中添加仓库接口的扫描路径 <jpa:repositories base-package="cn.luxh.app.repository"/>

2）编写领域实体，需要按照JPA规范

3）编写仓库Repository<T,ID>接口，依靠Spring Data规范定义接口方法。

比如按照规范定义一个数据访问接口方法  List<User> findByName(String name);

Spring Data JPA 就会自动转化为 select u from User u where u.name = ?1

--------------------

可以使用的仓库接口有：  
　　　　Repository： 　　　　　　　　　　是 Spring Data的一个核心接口，它不提供任何方法，开发者需要在自己定义的接口中声明需要的方法。

CrudRepository： 　 　　　　　　 继承Repository，提供增删改查方法，可以直接调用。

PagingAndSortingRepository：    继承CrudRepository，具有分页查询和排序功能

JpaRepository：                         继承PagingAndSortingRepository，针对JPA技术提供的接口

JpaSpecificationExecutor：          可以执行原生SQL查询

[http_www.springsource.org_spring-framework]: http://www.springsource.org/spring-framework
[http_olex.openlogic.com_packages_hibernate]: http://olex.openlogic.com/packages/hibernate
[http_www.springsource.org_spring-data_jpa]: http://www.springsource.org/spring-data/jpa
[http_www.springsource.org_spring-data_commons]: http://www.springsource.org/spring-data/commons
[http_ebr.springsource.com_repository_app_library]: http://ebr.springsource.com/repository/app/library
[copycode.gif]: /images/20220810/d33d6b3310ce4124bd2a2e4cea3ff225.png
[2012083116291850.jpg]: /images/20220810/b006e7f120f546a08da8f268c128ffca.png
[2012083117222672.jpg]: /images/20220810/e15cc5d2297b42de87e1efc61cfc9415.png
[2012083117225758.jpg]: /images/20220810/80b5dab6dd444ed69c3d781d58af4d5d.png
[2012083117233289.jpg]: /images/20220810/b4832b78fedb42148c7a84d5b7037d05.png