1.导入版本管理依赖 到父项目里

<dependencyManagement><dependencies><dependency><groupId>org.springframework.data</groupId><artifactId>spring-data-bom</artifactId><version>2021.1.10</version><scope>import</scope><type>pom</type></dependency></dependencies>
</dependencyManagement>

2.导入spring-data-jpa 依赖 在子模块

  <dependencies><!--    Junit    --><dependency><groupId>junit</groupId><artifactId>junit</artifactId><version>4.12</version><scope>test</scope></dependency><!--   hibernate --><dependency><groupId>org.hibernate</groupId><artifactId>hibernate-entitymanager</artifactId><version>5.4.32.Final</version></dependency><!--        mysql  --><dependency><groupId>mysql</groupId><artifactId>mysql-connector-java</artifactId><version>5.1.47</version></dependency><!--        jpa  --><dependency><groupId>org.springframework.data</groupId><artifactId>spring-data-jpa</artifactId></dependency><!--     连接池   --><dependency><groupId>com.alibaba</groupId><artifactId>druid</artifactId><version>1.2.8</version></dependency><!--     spring -  test    --><dependency><groupId>org.springframework</groupId><artifactId>spring-test</artifactId><version>5.3.10</version><scope>test</scope></dependency></dependencies>

3.创建实体类

package com.kuang.pojo;import javax.persistence.*;@Entity//作为 hibernate实体类
@Table(name = "tb_customer")//映射的表名
public class Customer {/*** @Id: 声明主键的配置* @GeneratedValue: 配置主键的生成策略*        strategy :*            1. GenerationType.IDENTITY :自增 mysql*               底层数据库必须支持自动增长 (底层数据库支持的自动增长方式，对id自增)*            2. GenerationType.SEQUENCE : 序列 ，oracle*               底层书库必须支持序列*            3. GenerationType.TABLE : jpa 提供的一种机制， 通过一张数据库表的形式帮助我们完成主键的配置*            4. GenerationType.AUTO : 由程序自动的帮助我们选择主键生成策略*   @Column(name = "cust_id") 配置属性和字段的映射关系*       name: 数据库表中字段的名称*/@Id@GeneratedValue(strategy = GenerationType.IDENTITY)@Column(name = "cust_id")private Long custId;//客户的主键@Column(name = "cust_name")private String custName;//客户的名称@Column(name = "cust_address")private String custAddress;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 getCustAddress() {return custAddress;}public void setCustAddress(String custAddress) {this.custAddress = custAddress;}@Overridepublic String toString() {return "Customer{" +"custId=" + custId +", custName='" + custName + '\'' +", custAddress='" + custAddress + '\'' +'}';}
}

4.创建spring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:jpa="http://www.springframework.org/schema/data/jpa" xmlns:tx="http://www.springframework.org/schema/tx"xsi:schemaLocation="http://www.springframework.org/schema/beanshttps://www.springframework.org/schema/beans/spring-beans.xsdhttp://www.springframework.org/schema/data/jpahttps://www.springframework.org/schema/data/jpa/spring-jpa.xsd http://www.springframework.org/schema/tx http://www.springframework.org/schema/tx/spring-tx.xsd"><!-- 用于整合 jpa  相当于 @EnableJpaRepositories       --><jpa:repositories base-package="com.kuang.repositories"entity-manager-factory-ref="entityManagerFactory"transaction-manager-ref="transactionManager"/><!-- 配置 bean  EntityManagerFactory    --><bean id="entityManagerFactory" class="org.springframework.orm.jpa.LocalContainerEntityManagerFactoryBean"><property name="jpaVendorAdapter"><!--         Hibernate 实现   --><bean class="org.springframework.orm.jpa.vendor.HibernateJpaVendorAdapter"><!--            是否自动的表的生成  true 相当于之前的 update  false 相当于 none  --><property name="generateDdl" value="true"/><!--             是否显示sql   --><property name="showSql" value="true"/></bean></property><!--        扫描实体类的包  来决定哪些实体类做 ORM映射  --><property name="packagesToScan" value="com.kuang.pojo"></property>
<!--    数据源   druid --><property name="dataSource" ref="dataSource"/></bean><!--    数据源--><bean class="com.alibaba.druid.pool.DruidDataSource" id="dataSource"><property name="driverClassName" value="com.mysql.jdbc.Driver"/><property name="url" value="jdbc:mysql://localhost:3306/springdata_jpa?useUnicode=true&amp;useSSL=false&amp;characterEncoding=UTF-8"/><property name="username" value="root"/><property name="password" value="2001"/></bean><!--    声明式事务  --><bean class="org.springframework.orm.jpa.JpaTransactionManager" id="transactionManager"><property name="entityManagerFactory" ref="entityManagerFactory"/></bean>
<!-- 启动注解方式的声明式事务--><tx:annotation-driven transaction-manager="transactionManager"></tx:annotation-driven>
</beans>

5.创建Repository接口

package com.kuang.repositories;import com.kuang.pojo.Customer;
import org.springframework.data.repository.CrudRepository;public interface CustomerRepository extends CrudRepository<Customer,Long> {}

6.测试通过主键查询

package com.kuang.test;import com.kuang.pojo.Customer;
import com.kuang.repositories.CustomerRepository;
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.Optional;@ContextConfiguration("/spring.xml")
@RunWith(SpringJUnit4ClassRunner.class)
public class SpringDataJpaTest {@Autowiredprivate CustomerRepository customerRepository;@Testpublic void select() {Optional<Customer> byId = customerRepository.findById(1L);Customer customer = byId.get();System.out.println(customer);}
}

package com.kuang.test;import com.kuang.pojo.Customer;
import com.kuang.repositories.CustomerRepository;
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.Optional;@ContextConfiguration("/spring.xml")
@RunWith(SpringJUnit4ClassRunner.class)
public class SpringDataJpaTest {@Autowiredprivate CustomerRepository customerRepository;@Testpublic void select() {Optional<Customer> byId = customerRepository.findById(1L);Customer customer = byId.get();System.out.println(customer);}@Testpublic void insert() {Customer customer = new Customer();customer.setCustAddress("南环路");customer.setCustName("豪哥");Customer save = customerRepository.save(customer);save.setCustAddress("刘备");System.out.println(customer);}@Testpublic void update() {Customer customer = new Customer();customer.setCustId(1L);customer.setCustAddress("栖霞路");customer.setCustName("张飞");Customer save = customerRepository.save(customer);}@Testpublic void remove() {Customer customer = new Customer();customer.setCustId(1L);customerRepository.delete(customer);}
}