spring data jpa对jpa进行了一次完整的封装
JPA是一套规范，内部是有接口和抽象类组成的。hibernate是一套成熟的ORM框架，而且Hibernate实现了JPA规范，所以也可以称hibernate为JPA的一种实现方式，我们使用JPA的API编程，意味着站在更高的角度上看待问题（面向接口编程）Spring Data JPA是Spring提供的一套对JPA操作更加高级的封装，是在JPA规范下的专门用来进行数据持久化的解决方案。
Spring Data JPA 是 Spring 基于 ORM 框架、JPA 规范的基础上封装的一套JPA应用框架，可使开发者用极简的代码即可实现对数据库的访问和操作。它提供了包括增删改查等在内的常用功能，且易于扩展！学习并使用 Spring Data JPA 可以极大提高开发效率！
<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>
整合Spring Data JPA与Spring
<?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">
<!--spring和spring-data-jpa的整合-->
<!--1.创建entityManagerFactory对象交给spring管理-->
<bean id="entityManagerFactory" class="org.springframework.orm.jpa.LocalContainerEntityManagerFactoryBean">
<!--数据库注入-->
<property name="dataSource" ref="dataSource"/>
<!--配置包的扫描-->
<property name="packagesToScan" value="com.ytkj.entity"/>
<!--jpa实现厂家-->
<property name="persistenceProvider">
<bean class="org.hibernate.jpa.HibernatePersistenceProvider"></bean>
</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" />
<!--是否显示sql语句-->
<property name="showSql" value="true" />
</bean>
</property>
<!--jpa方言：高级特性-->
<property name="jpaDialect">
<bean class="org.springframework.orm.jpa.vendor.HibernateJpaDialect" />
</property>
</bean>
<!--2.创建数据连接池-->
<bean id="dataSource" class="com.mchange.v2.c3p0.ComboPooledDataSource">
<!--数据库信息-->
<property name="driverClass" value="com.mysql.jdbc.Driver"/>
<property name="jdbcUrl" value="jdbc:mysql://192.168.2.100:3306/ytkj?serverTimeZone=UTC"/>
<property name="user" value="root"/>
<property name="password" value="123456"/>
</bean>
<!--3.整合spring-data-jpa-->
<jpa:repositories base-package="com.ytkj.dao" transaction-manager-ref="transacManager" entity-manager-factory-ref="entityManagerFactory"></jpa:repositories>
<!--4.配置事务管理器-->
<bean id="transacManager" class="org.springframework.orm.jpa.JpaTransactionManager">
<property name="entityManagerFactory" ref="entityManagerFactory" />
</bean>
<!--5.声明式事务-->
<tx:advice id="txAdvice" transaction-manager="transacManager">
<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(* com.ytkj.service.*.*(..))" />
<aop:advisor advice-ref="txAdvice" pointcut-ref="pointcut" />
</aop:config>
<context:component-scan base-package="com.ytkj"></context:component-scan>
</beans>
Spring Data JPA是spring提供的一款对于数据访问层（Dao层）的框架，使用Spring Data JPA，只需要按照框架的规范提供dao接口，不需要实现类就可以完成数据库的增删改查、分页查询等方法的定义，极大的简化了我们的开发过程。
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，并实现JpaRepository和JpaSpecificationExecutor
2.提供相应的泛型
package com.ytkj.entity;
import javax.persistence.*;
import java.io.Serializable;
/**
* @Entity
* 作用：指定当前类是实体类。
* @Table
* 作用：指定实体类和表之间的对应关系。
* 属性：
* name：指定数据库表的名称
* @Id
* 作用：指定当前字段是主键。
* @GeneratedValue
* 作用：指定主键的生成方式。。
* 属性：
* strategy ：指定主键生成策略。
* @Column
* 作用：指定实体类属性和数据库表之间的对应关系
* 属性：
* name：指定数据库表的列名称。
* unique：是否唯一
* nullable：是否可以为空
* inserttable：是否可以插入
* updateable：是否可以更新
* columnDefinition: 定义建表时创建此列的DDL
* secondaryTable: 从表名。如果此列不建在主表上（默认建在主表），该属性定义该列所在从表的名字搭建开发环境[重点]
*
* 客户实体类
* 配置映射关系
* 实体类和表映射
* 实体类属性和表字段映射
*/
@Entity
@Table(name = "cst_customer")
public class Customer implements Serializable {
/**
* 声明主键配置
*/
@Id
/**
* 配置主键的生成策略
*/
@GeneratedValue(strategy = GenerationType.IDENTITY)
/**
* 指定实体类属性和数据库表之间的对应关系
*/
@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;//客户行业
@Column(name ="cust_level")
private String custLevel;//客户级别
@Column(name ="cust_address")
private String custAddress;//客户地址
@Column(name = "cust_phone")
private String custPhone;//客户电话
public Long getCustId() {
return custId;
}
public void setCustId(Long custId) {
this.custId = custId;
}
public String getCustName() {
return custName;
}
public void setCustName(String custName) {
this.custName = custName;
}
public String getCustSource() {
return custSource;
}
public void setCustSource(String custSource) {
this.custSource = custSource;
}
public String getCustIndustry() {
return custIndustry;
}
public void setCustIndustry(String custIndustry) {
this.custIndustry = custIndustry;
}
public String getCustLevel() {
return custLevel;
}
public void setCustLevel(String custLevel) {
this.custLevel = custLevel;
}
public String getCustAddress() {
return custAddress;
}
public void setCustAddress(String custAddress) {
this.custAddress = custAddress;
}
public String getCustPhone() {
return custPhone;
}
public void setCustPhone(String custPhone) {
this.custPhone = custPhone;
}
@Override
public String toString() {
return "Customer{" +
"custId=" + custId +
", custName='" + custName + '\'' +
", custSource='" + custSource + '\'' +
", custIndustry='" + custIndustry + '\'' +
", custLevel='" + custLevel + '\'' +
", custAddress='" + custAddress + '\'' +
", custPhone='" + custPhone + '\'' +
'}';
}
}
package com.ytkj.dao; import com.ytkj.entity.Customer; import org.springframework.data.jpa.repository.JpaRepository; import org.springframework.data.jpa.repository.JpaSpecificationExecutor; import org.springframework.stereotype.Component; import org.springframework.stereotype.Repository; /** * JpaRepository<实体类类型，主键类型>：用来完成基本CRUD操作 * JpaSpecificationExecutor<实体类类型>：用于复杂查询（分页等查询操作） */ @Repository public interface CustomerDao extends JpaRepository<Customer,Long>, JpaSpecificationExecutor<Customer> { }
import com.ytkj.dao.CustomerDao; import com.ytkj.entity.Customer; 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 java.util.List; @RunWith(SpringJUnit4ClassRunner.class)//声明spring提供的单元测试环境 @ContextConfiguration(locations = "classpath:applicationContext.xml")//指定spring容器的配置信息 public class SpringdatajpaTest { @Autowired CustomerDao customerDao; /** * 根据id查询 */ @Test public void findById(){ Customer customer = customerDao.findOne(1l); System.out.println(customer); } /** * 查询所有 */ @Test public void findAll(){ List<Customer> list = customerDao.findAll(); for (Customer customer : list) { System.out.println(customer); } } /** * save: * 保存或者更新 * 根据传递的对象是否存在主键id.如果没有主键id就是保存 * 存在主键id,根据id查询，在跟新数据 */ @Test public void save(){ Customer customer=new Customer(); customer.setCustName("hahahahah"); customer.setCustPhone("119"); customerDao.save(customer);//没有id，保存 } @Test public void save2(){ Customer customer=new Customer(); customer.setCustId(4L); customer.setCustName("中国人"); customer.setCustPhone("0520"); customer.setCustAddress("曲靖"); customerDao.save(customer);//有id，更新 } /** * 根据id删除 */ @Test public void deleteById(){ customerDao.delete(6l); } }
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