SpringDataJPA

一.SpringDataJpa入门案列1.搭建环境1.1 创建工程导入jar包1.2 配置配置文件1.3 创建客户实体类并配置映射关系1.4 编写SpringDataJpa规范的Dao接口1.5 测试代码1.5.1 findall查询所有1.5.2 save保存和更新1.5.3 delete删除记录 2.复杂查询2.1 findone （立即加载）2.2 getone （延迟加载）2.3 自定义方法查询2.4自定义方法更新2.5 在JPA中用SQL查询2.5.1 查询全部2.5.2 条件查询 2.6 方法命名规则查询

一.SpringDataJpa入门案列

1.搭建环境

1.1 创建工程导入jar包

<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> <dependency> <groupId>javax.xml.bind</groupId> <artifactId>jaxb-api</artifactId> <version>2.3.0</version> </dependency> <dependency> <groupId>com.sun.xml.bind</groupId> <artifactId>jaxb-impl</artifactId> <version>2.3.0</version> </dependency> <dependency> <groupId>com.sun.xml.bind</groupId> <artifactId>jaxb-core</artifactId> <version>2.3.0</version> </dependency> <dependency> <groupId>javax.activation</groupId> <artifactId>activation</artifactId> <version>1.1.1</version> </dependency>

1.2 配置配置文件

<?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"> <bean id="dataSources" class="com.mchange.v2.c3p0.ComboPooledDataSource"> <property name="driverClass" value="com.mysql.jdbc.Driver" /> <property name="jdbcUrl" value="jdbc:mysql://localhost:3306/jpa" /> <property name="user" value="root" /> <property name="password" value="root" /> </bean> <!--1.创建entityManagerfactory对象交给spring容器管理--> <bean id="entityManager" class="org.springframework.orm.jpa.LocalContainerEntityManagerFactoryBean"> <property name="dataSource" ref="dataSources"></property> <!-- 2.配置的是扫描的包，实体类所在包--> <property name="packagesToScan" value="cn.xkm.domain"></property> <!-- 3.jpa实现厂家--> <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"> <!-- 配置是否自动创建数据库表--> <property name="generateDdl" value="false" /> <!-- 指定数据库类型--> <property name="database" value="MYSQL" /> <!-- 数据库方言，支持的特有语法--> <property name="databasePlatform" value="org.hibernate.dialect.MySQLDialect" /> <property name="showSql" value="true" /> </bean> </property> <!-- jpa的方言：高级的特性--> <property name="jpaDialect"> <bean class="org.springframework.orm.jpa.vendor.HibernateJpaDialect"></bean> </property> </bean> <!-- 整合springdatajpa--> <jpa:repositories base-package="cn.xkm.dao" transaction-manager-ref="transactionManager" entity-manager-factory-ref="entityManager"></jpa:repositories> <bean id="transactionManager" class="org.springframework.orm.jpa.JpaTransactionManager"> <property name="entityManagerFactory" ref="entityManager"></property> </bean> <!-- spring声明式事务,此处省略--> <!-- 注解包扫描--> <context:component-scan base-package="cn.xkm"></context:component-scan> </beans>

1.3 创建客户实体类并配置映射关系

package cn.xkm.domain; import javax.persistence.*; @Entity @Table(name="cst_customer") public class Customer { @Id @GeneratedValue(strategy = GenerationType.IDENTITY) @Column(name = "cust_id") private long custId; //客户主键 @Column(name = "cust_name") private String custName; //客户名称 @Column(name = "cust_source") private String custSource; //客户来源 @Column(name = "cust_industry") private String custIndustry; //客户级别 @Column(name = "cust_level") private String custLevel; //客户所属行业 @Column(name = "cust_address") private String custAddress; //客户地址 @Column(name = "cust_phone") private String custPhone; //客户联系方式

1.4 编写SpringDataJpa规范的Dao接口

不需要写额外代码，只要继承两个接口就行

//符合SpringDataJpa的Dao曾接口规范 //JpaRepository<操作的实体类类型,实体类中主键属性的类型> // *封装了基本的CRUD操作 //JpaSpecificationExecutor<操作的实体类类型> // *封装了复杂查询（分页） public interface JpaDao extends JpaRepository<Customer,Long>, JpaSpecificationExecutor<Customer> { }

1.5 测试代码

1.5.1 findall查询所有

//声明Spring提供的单元测试环境 @RunWith(SpringJUnit4ClassRunner.class) //指定spring容器的配置信息 @ContextConfiguration(locations = "classpath:applicationContext.xml") public class JpaTest { @Autowired private JpaDao jpaDao; @Test public void findall(){ List<Customer> all = jpaDao.findAll(); all.forEach(a-> System.out.println(a)); } }

1.5.2 save保存和更新

如果主键存在，则更新，如果主键不存在则保存，都是save

jpaDao.save(customer);

1.5.3 delete删除记录

jpaDao.delete(4l);

2.复杂查询

2.1 findone （立即加载）

Customer one = jpaDao.findOne(5l); System.out.println(one);

2.2 getone （延迟加载）

需要加上 @Transactional注解防止报错

@Test @Transactional public void getOne(){ Customer one = jpaDao.getOne(5l); System.out.println(one); }

2.3 自定义方法查询

在Dao接口上添加@Query注解，并设定查询语句

public interface JpaDao extends JpaRepository<Customer,Long>, JpaSpecificationExecutor<Customer> { @Query(value = "from Customer where custName = ? and custId = ?") public List<Customer> findJpql(String custName,long id); }

2.4自定义方法更新

注： 1.dao接口中方法要加上 @Modifying，代表此操作是更新 2.更新操作要添加事务管理的注解 @Transactional 3.更新会默认回滚，要将默认回滚设为False，否则不成功 @Rollback(false)

@Query(value = "update Customer set custName = ? where custId = ?") @Modifying//代表此操作是更新 public void updateJpql(String custName,long id); @Test @Transactional @Rollback(false) public void update(){ jpaDao.updateJpql("xkm",3l); } }

2.5 在JPA中用SQL查询

2.5.1 查询全部

1.在dao中的 @Query注解中输入查询语句，并开启sql查询nativeQuery = true，默认为false 2.返回值设为List<Object[]>

@Query(value = "select * from cst_customer",nativeQuery = true) public List<Object[]> findAllSql(); List<Object[]> objects = jpaDao.findAllSql(); for (Object[] object : objects) { String s = Arrays.toString(object); System.out.println(s);

2.5.2 条件查询

添加参数即可

@Query(value = "select * from cst_customer where cust_name = ?",nativeQuery = true) public List<Object[]> findoneSql(String name);

2.6 方法命名规则查询

注：用提供好的命名规则，可以不用自己定义查询语句，例如：findBy开头

public Customer findByCustId(Long id); Customer byCustId = jpaDao.findByCustId(4l); System.out.println(byCustId);