Spring Data Jpa使用

Spring Data Jpa简介

Spring Data JPA是Spring Data框架的一个模块。
Spring Data JPA依赖于Spring的核心jar,JPA只有接口和注解，Spring Data JPA的功能实现默是使用的Hibernate，因此还必须引入Hibernate对JPA的支持（整合）项目hibernate-entitymanager。

JPA编程是通过EntityManagerFactory（类似SessionFactory），获得EntityManager （类似Session）进行增删改查，CRUD的方法分别为：
增加 persist()、修改 merge()、删除 remove()、查询 find()

Spring Data JPA配置和基本使用

1.引入spring data jpa和hibernate-entitymanager的依赖；
2.配置DataSource，配置EntityManagerFactory，配置事务，配置JPA扫描。
3.编写接口继承Repository系列接口，按照JPA规范编写相关方法。

具体实例

依赖：

<properties>
    <spring.version>4.0.3.RELEASEspring.version>
    <spring.groupId>org.springframeworkspring.groupId>
    <druid.version>1.0.28druid.version>
    <mysql.version>5.1.45mysql.version>
    <spring.data.jpa.version>1.7.0.RELEASEspring.data.jpa.version>
    <hibernate.entitymanager.version>4.3.6.Finalhibernate.entitymanager.version>
    <junit.version>4.12junit.version>
    <aspectjweaver.version>1.8.1aspectjweaver.version>
properties>
<dependencies>
    <dependency>
        <groupId>${spring.groupId}groupId>
        <artifactId>spring-beansartifactId>
        <version>${spring.version}version>
    dependency>
    <dependency>
        <groupId>${spring.groupId}groupId>
        <artifactId>spring-contextartifactId>
        <version>${spring.version}version>
    dependency>
    <dependency>
        <groupId>${spring.groupId}groupId>
        <artifactId>spring-coreartifactId>
        <version>${spring.version}version>
    dependency>
    <dependency>
        <groupId>${spring.groupId}groupId>
        <artifactId>spring-testartifactId>
        <version>${spring.version}version>
    dependency>
    <dependency>
        <groupId>${spring.groupId}groupId>
        <artifactId>spring-jdbcartifactId>
        <version>${spring.version}version>
    dependency>
    <dependency>
        <groupId>${spring.groupId}groupId>
        <artifactId>spring-txartifactId>
        <version>${spring.version}version>
    dependency>
    <dependency>
        <groupId>com.alibabagroupId>
        <artifactId>druidartifactId>
        <version>${druid.version}version>
    dependency>
    <dependency>
        <groupId>mysqlgroupId>
        <artifactId>mysql-connector-javaartifactId>
        <version>${mysql.version}version>
    dependency>
    <dependency>
        <groupId>org.springframework.datagroupId>
        <artifactId>spring-data-jpaartifactId>
        <version>${spring.data.jpa.version}version>
    dependency>
    <dependency>
        <groupId>org.hibernategroupId>
        <artifactId>hibernate-entitymanagerartifactId>
        <version>${hibernate.entitymanager.version}version>
    dependency>
    <dependency>
        <groupId>junitgroupId>
        <artifactId>junitartifactId>
        <version>${junit.version}version>
    dependency>
    <dependency>
        <groupId>org.aspectjgroupId>
        <artifactId>aspectjweaverartifactId>
        <version>${aspectjweaver.version}version>
    dependency>
dependencies>

spring.xml

<beans xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
       xmlns="http://www.springframework.org/schema/beans" xmlns:aop="http://www.springframework.org/schema/aop"
       xmlns:context="http://www.springframework.org/schema/context" xmlns:tx="http://www.springframework.org/schema/tx"
       xmlns:cache="http://www.springframework.org/schema/cache" xmlns:p="http://www.springframework.org/schema/p"
       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-4.0.xsd
     http://www.springframework.org/schema/aop
     http://www.springframework.org/schema/aop/spring-aop-4.0.xsd
     http://www.springframework.org/schema/context
     http://www.springframework.org/schema/context/spring-context-4.0.xsd
     http://www.springframework.org/schema/tx
     http://www.springframework.org/schema/tx/spring-tx-4.0.xsd
     http://www.springframework.org/schema/cache http://www.springframework.org/schema/cache/spring-cache-4.0.xsd http://www.springframework.org/schema/data/jpa http://www.springframework.org/schema/data/jpa/spring-jpa.xsd">
    <context:component-scan base-package="com.tommy.myapp">
        <context:exclude-filter type="annotation" expression="org.springframework.stereotype.Controller"/>
    context:component-scan>
    <context:property-placeholder location="classpath:db.properties"/>
    
    <bean id="dataSource" class="com.alibaba.druid.pool.DruidDataSource" init-method="init" destroy-method="close">
        
        <property name="url" value="${db.url}"/>
        <property name="username" value="${db.username}"/>
        <property name="password" value="${db.password}"/>
        
        <property name="initialSize" value="10"/>
        <property name="minIdle" value="10"/>
        <property name="maxActive" value="100"/>
        
        <property name="maxWait" value="60000"/>
        
        <property name="timeBetweenEvictionRunsMillis" value="60000"/>
        
        <property name="minEvictableIdleTimeMillis" value="300000"/>
        <property name="validationQuery" value="${db.test_sql}"/>
        
        <property name="testWhileIdle" value="true"/>
        
        <property name="testOnBorrow" value="false"/>
        
        <property name="testOnReturn" value="false"/>
        
        <property name="poolPreparedStatements" value="true"/>
        <property name="maxPoolPreparedStatementPerConnectionSize" value="20"/>
        
        <property name="filters" value="stat"/>
    bean>
    
    <bean id="entityManagerFactory" class="org.springframework.orm.jpa.LocalContainerEntityManagerFactoryBean">
        
        <property name="dataSource" ref="dataSource"/>
        
        <property name="packagesToScan" value="com.tommy.myapp.entity"/>
        
        <property name="jpaVendorAdapter">
            <bean class="org.springframework.orm.jpa.vendor.HibernateJpaVendorAdapter">
                
                <property name="database" value="${db.type}"/>
                
                <property name="generateDdl" value="true"/>
                
                <property name="databasePlatform" value="${db.dialect}"/>
                
                <property name="showSql" value="true"/>
            bean>
        property>
        
        <property name="jpaProperties">
            <props>
                <prop key="hibernate.format_sql">trueprop>
            props>
        property>
    bean>
    
    <bean id="transactionManager" class="org.springframework.orm.jpa.JpaTransactionManager">
        <property name="entityManagerFactory" ref="entityManagerFactory"/>
    bean>
    
    <tx:annotation-driven transaction-manager="transactionManager"/>
    <tx:advice id="transactionAdvice" transaction-manager="transactionManager">
        <tx:attributes>
            <tx:method name="add*" propagation="REQUIRED"/>
            <tx:method name="append*" propagation="REQUIRED"/>
            <tx:method name="insert*" propagation="REQUIRED"/>
            <tx:method name="save*" propagation="REQUIRED"/>
            <tx:method name="update*" propagation="REQUIRED"/>
            <tx:method name="modify*" propagation="REQUIRED"/>
            <tx:method name="edit*" propagation="REQUIRED"/>
            <tx:method name="delete*" propagation="REQUIRED"/>
            <tx:method name="remove*" propagation="REQUIRED"/>
            <tx:method name="repair" propagation="REQUIRED"/>
            <tx:method name="get*" propagation="SUPPORTS"/>
            <tx:method name="select*" propagation="SUPPORTS"/>
            <tx:method name="find*" propagation="SUPPORTS"/>
            <tx:method name="load*" propagation="SUPPORTS"/>
            <tx:method name="search*" propagation="SUPPORTS"/>
            <tx:method name="*" propagation="SUPPORTS"/>
        tx:attributes>
    tx:advice>
    
    <aop:config proxy-target-class="true">
        <aop:pointcut id="myPointcut"
                      expression="execution(* com.tommy.myapp.service.impl.*.*(..))"/>
        <aop:advisor advice-ref="transactionAdvice" pointcut-ref="myPointcut"/>
    aop:config>
    <jpa:repositories base-package="com.tommy.myapp.dao" entity-manager-factory-ref="entityManagerFactory"
                      transaction-manager-ref="transactionManager">
    jpa:repositories>
beans>

db.properties:

db.type=MYSQL
db.dialect=org.hibernate.dialect.MySQL5InnoDBDialect
db.url=jdbc:mysql://192.168.74.135:3306/test?useUnicode=true&characterEncoding=utf8
db.username=root
db.password=123456
db.test_sql=select 1

User.java

@Entity
@Table(name = "t_user")
public class User {
    @Id
    @GeneratedValue(strategy = GenerationType.AUTO)
    private Long id;
    private String name;
    private Date birthday;
    public Long getId() {
        return id;
    }
    public void setId(Long id) {
        this.id = id;
    }
    public String getName() {
        return name;
    }
    public void setName(String name) {
        this.name = name;
    }
    public Date getBirthday() {
        return birthday;
    }
    public void setBirthday(Date birthday) {
        this.birthday = birthday;
    }
}

UserDao.java

public interface UserDao extends JpaRepository<User,Long> {
    User findByName(String name);
}

单元测试

@RunWith(SpringJUnit4ClassRunner.class)
@ContextConfiguration(locations = "classpath:spring.xml")
@TransactionConfiguration(transactionManager = "transactionManager",defaultRollback = true) // 单元测试完毕回滚事务
@Transactional
public class UserDaoTest {
    @Autowired
    private UserDao userDao;
    private Long dbUserId = 0L;
    @Test
    public void testSave() {
        User user = new User();
        user.setName("test");
        user.setBirthday(new Date());
        user = this.userDao.save(user);
        assert user.getId() > 0;
        dbUserId = user.getId();
    }
    @Test
    public void testFindUserById() {
        User user = this.userDao.findOne(dbUserId);
        assert user != null;
    }
    @Test
    public void testFindUserByName() {
        String name = "test";
        User user = this.userDao.findByName(name);
        assert user != null;
    }
}

相关问题：
1.org.hibernate.id.IdentifierGenerationException: ids for this class must be manually assigned before
解决：在实体类的id字段上加入@GeneratedValue(strategy = GenerationType.AUTO)注解

@Id
@GeneratedValue(strategy = GenerationType.AUTO)
private Long id;

参考：Spring Data JPA框架、使用Spring Data JPA简化JPA开发、Spring Data系列入门