Spring 整合 JPA

spring 整合 jpa 客户的基本CRUD

依赖

<properties>
    <spring.version>4.2.4.RELEASE</spring.version>
    <hibernate.version>5.0.7.Final</hibernate.version>
    <slf4j.version>1.6.6</slf4j.version>
    <log4j.version>1.2.12</log4j.version>
    <c3p0.version>0.9.1.2</c3p0.version>
    <mysql.version>5.1.6</mysql.version>
</properties>
<dependencies>
    <!-- junit单元测试 -->
    <dependency>
        <groupId>junit</groupId>
        <artifactId>junit</artifactId>
        <version>4.9</version>
        <scope>test</scope>
    </dependency>
    <!-- spring beg -->
    <dependency>
        <groupId>org.aspectj</groupId>
        <artifactId>aspectjweaver</artifactId>
        <version>1.6.8</version>
    </dependency>
    <dependency>
        <groupId>org.springframework</groupId>
        <artifactId>spring-aop</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-context-support</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-beans</artifactId>
        <version>${spring.version}</version>
    </dependency>
    <dependency>
        <groupId>org.springframework</groupId>
        <artifactId>spring-core</artifactId>
        <version>${spring.version}</version>
    </dependency>
    <!-- spring end -->
    <!-- hibernate beg -->
    <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>
    <dependency>
        <groupId>org.hibernate</groupId>
        <artifactId>hibernate-validator</artifactId>
        <version>5.2.1.Final</version>
    </dependency>
    <!-- hibernate end -->
    <!-- c3p0 beg -->
    <dependency>
        <groupId>c3p0</groupId>
        <artifactId>c3p0</artifactId>
        <version>${c3p0.version}</version>
    </dependency>
    <!-- c3p0 end -->
    <!-- log end -->
    <dependency>
        <groupId>log4j</groupId>
        <artifactId>log4j</artifactId>
        <version>${log4j.version}</version>
    </dependency>
    <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>
    <!-- log end -->
    <dependency>
        <groupId>mysql</groupId>
        <artifactId>mysql-connector-java</artifactId>
        <version>${mysql.version}</version>
    </dependency>
    <dependency>
        <groupId>org.springframework.data</groupId>
        <artifactId>spring-data-jpa</artifactId>
        <version>1.9.0.RELEASE</version>
    </dependency>
    <dependency>
        <groupId>org.springframework</groupId>
        <artifactId>spring-test</artifactId>
        <version>4.2.4.RELEASE</version>
    </dependency>
    <!-- el beg 使用spring data jpa 必须引入 -->
    <dependency>
        <groupId>javax.el</groupId>
        <artifactId>javax.el-api</artifactId>
        <version>2.2.4</version>
    </dependency>
    <dependency>
        <groupId>org.glassfish.web</groupId>
        <artifactId>javax.el</artifactId>
        <version>2.2.4</version>
    </dependency>
    <!-- el end -->
</dependencies>

spring-jpa 配置文件

<?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:aop="http://www.springframework.org/schema/aop"
       xmlns:context="http://www.springframework.org/schema/context"
       xmlns:jdbc="http://www.springframework.org/schema/jdbc"
       xmlns:tx="http://www.springframework.org/schema/tx"
       xmlns:jpa="http://www.springframework.org/schema/data/jpa"
       xmlns:task="http://www.springframework.org/schema/task"
       xsi:schemaLocation="
http://www.springframework.org/schema/beans
http://www.springframework.org/schema/beans/spring-beans.xsd
http://www.springframework.org/schema/aop
http://www.springframework.org/schema/aop/spring-aop.xsd
http://www.springframework.org/schema/context
http://www.springframework.org/schema/context/spring-context.xsd
http://www.springframework.org/schema/jdbc
http://www.springframework.org/schema/jdbc/spring-jdbc.xsd
http://www.springframework.org/schema/tx
http://www.springframework.org/schema/tx/spring-tx.xsd
http://www.springframework.org/schema/data/jpa
http://www.springframework.org/schema/data/jpa/spring-jpa.xsd">

    <!-- 1.dataSource 配置数据库连接池-->
    <bean id="dataSource" class="com.mchange.v2.c3p0.ComboPooledDataSource">
        <property name="driverClass" value="com.mysql.jdbc.Driver"/>
        <property name="jdbcUrl" value="jdbc:mysql:///jpa"/>
        <property name="user" value="root"/>
        <property name="password" value="root"/>
    </bean>
    <!-- 2.配置entityManagerFactory -->
    <bean id="entityManagerFactory"
          class="org.springframework.orm.jpa.LocalContainerEntityManagerFactoryBean">
        <property name="dataSource" ref="dataSource"/>
        <property name="packagesToScan" value="cn.itcast.entity"/>
        <property name="persistenceProvider">
            <bean class="org.hibernate.jpa.HibernatePersistenceProvider"/>
        </property>
        <!--JPA的供应商适配器-->
        <property name="jpaVendorAdapter">
            <bean
                    class="org.springframework.orm.jpa.vendor.HibernateJpaVendorAdapter">
                <property name="generateDdl" value="true"/>
                <property name="database" value="MYSQL"/>
                <property name="databasePlatform"
                          value="org.hibernate.dialect.MySQLDialect"/>
                <property name="showSql" value="true"/>
            </bean>
        </property>
        <property name="jpaDialect">
            <bean class="org.springframework.orm.jpa.vendor.HibernateJpaDialect"/>
        </property>
    </bean>
    <!-- 3.事务管理器-->
    <!-- JPA事务管理器 -->
    <bean id="transactionManager"
          class="org.springframework.orm.jpa.JpaTransactionManager">
        <property name="entityManagerFactory" ref="entityManagerFactory"/>
    </bean>
    <!-- 整合spring data jpa-->
    <jpa:repositories base-package="cn.itcast.dao"
                      transaction-manager-ref="transactionManager"
                      entity-manager-factory-ref="entityManagerFactory"></jpa:repositories>
    <!-- 4.txAdvice-->
    <tx:advice id="txAdvice" transaction-manager="transactionManager">
        <tx:attributes>
            <tx:method name="save*" propagation="REQUIRED"/>
            <tx:method name="insert*" propagation="REQUIRED"/>
            <tx:method name="update*" propagation="REQUIRED"/>
            <tx:method name="delete*" propagation="REQUIRED"/>
            <tx:method name="get*" read-only="true"/>
            <tx:method name="find*" read-only="true"/>
            <tx:method name="*" propagation="REQUIRED"/>
        </tx:attributes>
    </tx:advice>
    <!-- 5.aop-->
    <aop:config>
        <aop:pointcut id="pointcut" expression="execution(* cn.itcast.service.*.*(..))"/>
        <aop:advisor advice-ref="txAdvice" pointcut-ref="pointcut"/>
    </aop:config>
    <context:component-scan base-package="cn.itcast"></context:component-scan>
    <!--组装其它 配置文件-->
</beans>

实体类

import javax.persistence.Column;
import javax.persistence.Entity;
import javax.persistence.GeneratedValue;
import javax.persistence.GenerationType;
import javax.persistence.Id;
import javax.persistence.Table;
/**
 * 所有的注解都是使用JPA的规范提供的注解，
 * 所以在导入注解包的时候，一定要导入javax.persistence下的
 */
@Entity //声明实体类
@Table(name="cst_customer") //建立实体类和表的映射关系
public class Customer {
    @Id//声明当前私有属性为主键
    @GeneratedValue(strategy=GenerationType.IDENTITY) //配置主键的生成策略
    @Column(name="cust_id") //指定和表中cust_id字段的映射关系
    private Long custId;
    @Column(name="cust_name") //指定和表中cust_name字段的映射关系
    private String custName;
    @Column(name="cust_source")//指定和表中cust_source字段的映射关系
    private String custSource;
    @Column(name="cust_industry")//指定和表中cust_industry字段的映射关系
    private String custIndustry;
    @Column(name="cust_level")//指定和表中cust_level字段的映射关系
    private String custLevel;
    @Column(name="cust_address")//指定和表中cust_address字段的映射关系
    private String custAddress;
    @Column(name="cust_phone")//指定和表中cust_phone字段的映射关系
    private String custPhone;
}

编写符合 Spring Data JPA 规范的 Dao 层接口

在 Spring Data JPA 中，对于定义符合规范的 Dao 层接口，我们只需要遵循以下几点就可以了：

1. 创建一个 Dao 层接口，继承 JpaRepository 和 JpaSpecificationExecutor 接口
2. 提供相应的泛型

public interface CustomerDao extends JpaRepository<Customer, Long>, JpaSpecificationExecutor<Customer> {
    // jpql 查全部
    @Query("from Customer")
    List<Customer> findAll();
    // jpql 条件查询
    @Query("from Customer where cust_name = ?1")
    List<Customer> findByCustName(String custName);
    // jpql 更新 @Modifying 执行更新操作
    @Query("update Customer set cust_address = ?2 where cust_id = ?1")
    @Modifying
    void updateCustAddress(Long custId, String custAddress);
    // 原生 sql
    @Query(value = "select * from cst_customer", nativeQuery = true)
    List<Customer> findSql();
    //方法命名规则查询
    List<Customer> findByCustAddress(String custAddress);
    List<Customer> findByCustAddressLikeAndCustNameLike(String custAddress, String custName);
}

方法命名规则查询

就是在定义我们的查询方法的时候，需要按照spring data jpa所指定的命名规则进行命名

findBy + 方法属性名 + 查询方式 + [逻辑连接符 + 方法属性名 + 查询方式]...

优缺点：简单，但是如果条件特别多将导致方法名冗长。实际中方法命名和 jpql 结合使用。

jpql 查询

使用的是类名和属性名。@Query @Modifying

sql 查询

使用的是表名和字段名。@Query nativeQuery = true

测试类

@RunWith(SpringJUnit4ClassRunner.class)
@ContextConfiguration(locations = "classpath:spring/spring-jpa.xml")
public class CustomerDaoTest {
    @Autowired
    private CustomerDao customerDao;
    /**
     * 保存客户：调用save(obj)方法
     */
    @Test
    public void testSave() {
        Customer c = new Customer();
        c.setCustName("传智播客");
        customerDao.save(c);
    }
    /**
     * 修改客户：调用save(obj)方法
     * 根据是否存在 id ，进行保存或更新。
     */
    @Test
    public void testUpdate() {
        //根据id查询id为1的客户
        Customer customer = customerDao.findOne(1L);
        //修改客户名称
        customer.setCustName("传智播客顺义校区");
        //更新
        customerDao.save(customer);
    }
    /**
     * 根据id删除：调用delete(id)方法
     */
    @Test
    public void testDelete() {
        customerDao.delete(1L);
    }
    /**
     * 根据id查询：调用findOne(id)方法
     */
    @Test
    public void testFindById() {
        Customer customer = customerDao.findOne(1L);
        System.out.println(customer);
    }
	// jpql 查询
    @Test
    public void testFindAll(){
        List<Customer> customerList = customerDao.findAll();
        System.out.println(customerList);
    }
    @Test
    public void testFindByCustName(){
        List<Customer> customerList = customerDao.findByCustName("传智播客1");
        System.out.println(customerList);
    }

    /**
     * SpringDataJpa 更新/删除操作
     *      * 需要手动开启事务
     *      * 执行完毕后会回滚事务
     * 		@Rollback : 设置是否回滚 false|true
     */
    @Test
    @Transactional
    @Rollback(false)
    public void testUpdateCustAddress(){
        customerDao.updateCustAddress(1L, "西安校区");
    }
    // 方法命名查询
    @Test
    public void testFindByCustAddress(){
        List<Customer> customerList = customerDao.findByCustAddress("西安校区");
        System.out.println(customerList);
    }

    @Test
    public void testFindByCustAddressLikeAndCustNameLike(){
        List<Customer> customerList = customerDao.findByCustAddressLikeAndCustNameLike("西安%", "传智%");
        System.out.println(customerList);
    }
	// sql 查询
    @Test
    public void testFindSql(){
        List<Customer> customerList = customerDao.findSql();
        System.out.println(customerList);
    }
}

bugs

org.springframework.dao.InvalidDataAccessApiUsageException: Executing an update/delete query; nested exception is javax.persistence.TransactionRequiredException: Executing an update/delete query
原因：SpringDataJpa 更新/删除操作，必须手动加事务

org.springframework.dao.InvalidDataAccessResourceUsageException: could not extract ResultSet; SQL [n/a]; nested exception is org.hibernate.exception.SQLGrammarException: could not extract ResultSet
原因：sql 查询使用的是表名，不是实体名
@Query(value = "select * from Customer", nativeQuery = true)//错误
List<Customer> findSql();