SpringDataJpa学习(七) Spring Data JPA的快速入门

1、搭建Spring Data JPA开发环境

案例：客户的基本crud
i.环境搭建
创建工程导入坐标
配置spring的配置文件
编写实体类（customer）,使用jpa注解配置映射关系
ii.编写一个符合Spring Data JPA规范的dao层接口
	*只需要编写dao层接口，不需要编写dao层实现类
	*dao层接口规范
		1.需要继承两个接口（JpaRepository,JpaSpecificationExecutor）
		2.需要提供响应的泛型

1.1 引入Spring Data JPA的坐标

<?xml version="1.0" encoding="UTF-8"?>
<project xmlns="http://maven.apache.org/POM/4.0.0"
         xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
         xsi:schemaLocation="http://maven.apache.org/POM/4.0.0 http://maven.apache.org/xsd/maven-4.0.0.xsd">
    <modelVersion>4.0.0</modelVersion>

    <groupId>cn.ysk</groupId>
    <artifactId>jpa-day2</artifactId>
    <version>1.0-SNAPSHOT</version>

    <dependencies>
        <!-- https://mvnrepository.com/artifact/junit/junit -->
        <dependency>
            <groupId>junit</groupId>
            <artifactId>junit</artifactId>
            <version>4.12</version>
            <scope>test</scope>
        </dependency>

        <!-- https://mvnrepository.com/artifact/org.hibernate/hibernate-entitymanager -->
        <dependency>
            <groupId>org.hibernate</groupId>
            <artifactId>hibernate-entitymanager</artifactId>
            <version>5.4.4.Final</version>
        </dependency>

        <!-- https://mvnrepository.com/artifact/org.hibernate/hibernate-c3p0 -->
        <dependency>
            <groupId>org.hibernate</groupId>
            <artifactId>hibernate-c3p0</artifactId>
            <version>5.4.5.Final</version>
        </dependency>

        <!-- https://mvnrepository.com/artifact/log4j/log4j -->
        <dependency>
            <groupId>log4j</groupId>
            <artifactId>log4j</artifactId>
            <version>1.2.17</version>
        </dependency>

        <!-- https://mvnrepository.com/artifact/mysql/mysql-connector-java -->
        <dependency>
            <groupId>mysql</groupId>
            <artifactId>mysql-connector-java</artifactId>
            <version>5.1.47</version>
        </dependency>

        <dependency>
            <groupId>org.aspectj</groupId>
            <artifactId>aspectjweaver</artifactId>
            <version>1.9.5</version>
        </dependency>

        <dependency>
            <groupId>org.springframework</groupId>
            <artifactId>spring-aop</artifactId>
            <version>5.2.4.RELEASE</version>
        </dependency>

        <dependency>
            <groupId>org.springframework</groupId>
            <artifactId>spring-context-support</artifactId>
            <version>5.2.3.RELEASE</version>
        </dependency>

        <dependency>
            <groupId>org.springframework</groupId>
            <artifactId>spring-orm</artifactId>
            <version>5.2.4.RELEASE</version>
        </dependency>

        <dependency>
            <groupId>org.springframework</groupId>
            <artifactId>spring-beans</artifactId>
            <version>5.2.4.RELEASE</version>
        </dependency>

        <dependency>
            <groupId>org.springframework</groupId>
            <artifactId>spring-core</artifactId>
            <version>5.2.4.RELEASE</version>
        </dependency>

        <dependency>
            <groupId>org.hamcrest</groupId>
            <artifactId>hamcrest-core</artifactId>
            <version>2.1</version>
        </dependency>

        <dependency>
            <groupId>org.hibernate</groupId>
            <artifactId>hibernate-validator</artifactId>
            <version>5.4.1.Final</version>
        </dependency>

        <dependency>
            <groupId>c3p0</groupId>
            <artifactId>c3p0</artifactId>
            <version>0.9.1.2</version>
        </dependency>

        <dependency>
            <groupId>org.slf4j</groupId>
            <artifactId>slf4j-api</artifactId>
            <version>1.7.30</version>
        </dependency>

        <dependency>
            <groupId>org.log4j</groupId>
            <artifactId>slf4j-log4j12</artifactId>
            <version>1.2.12</version>
        </dependency>

        <dependency>
            <groupId>org.springframework.data</groupId>
            <artifactId>spring-data-jpa</artifactId>
            <version>2.2.5.RELEASE</version>
        </dependency>

        <dependency>
            <groupId>org.springframework</groupId>
            <artifactId>spring-test</artifactId>
            <version>5.2.4.RELEASE</version>
        </dependency>

        <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>
    </dependencies>


</project>

1.2 整合Spring Data JPA与Spring

/resources/applicationContext.xml

<?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"
       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的配置-->
    <!--1.创建entityManagerFactory对象交给spring容器处理-->
    <bean id="entityManagerFactory" class="org.springframework.orm.jpa.LocalContainerEntityManagerFactoryBean">
        <property name="dataSource" ref="dataSource" />
        <!--配置的扫描的包，实体类所在的包-->
        <property name="packagesToScan" value="cn.ysk.domian" />
        <!--jpa的实现厂家-->
        <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" />
                <!--指定的数据库类型-->
                <property name="database" value="MYSQL" />
                <property name="databasePlatform" value="org.hibernate.dialect.MySQLDialect" />
                <!--是否显示sql语句-->
                <property name="showSql" value="true" />
            </bean>
        </property>

        <!--jpa的方言-->
        <property name="jpaDialect">
            <bean class="org.springframework.orm.jpa.vendor.HibernateJpaDialect" />
        </property>

    </bean>

    <!--2.创建数据库连接池-->
    <bean id="dataSource" class="com.mchange.v2.c3p0.ComboPooledDataSource">
        <property name="user" value="root" />
        <property name="password" value="123456" />
        <property name="jdbcUrl" value="jdbc:mysql:///mytest" />
        <property name="driverClass" value="com.mysql.jdbc.Driver" />

    </bean>

    <!--3.整合spring data jpa-->
    <jpa:repositories base-package="cn.ysk.dao" transaction-manager-ref="transactionManager" entity-manager-factory-ref="entityManagerFactory"></jpa:repositories>

    <!--4.配置事务管理器-->
    <bean id="transactionManager" class="org.springframework.orm.jpa.JpaTransactionManager">
        <property name="entityManagerFactory" ref="entityManagerFactory"  />
    </bean>

    <!--5.声明式事务 略-->
    <!--6.配置包扫描-->
    <context:component-scan base-package="cn.ysk" ></context:component-scan>
</beans>

1.3 使用JPA注解配置映射关系

Customer.java

package cn.ysk.domian;

import javax.persistence.*;

/**
 * @Author ysk
 * @Date 2020/3/6 17:08
 * @Version 1.0
 * 1.实体类和表的映射关系
 * @Entity
 * @Table
 * 2.类中属性和表中字段的映射关系
 * @Id
 * @GeneratedValue
 */
@Entity
@Table(name = "cst_customer")
public class Customer {

    @Id
    @GeneratedValue(strategy = GenerationType.IDENTITY)
    @Column(name = "cust_id")
    private Long custId;
    @Column(name = "cust_name")
    private String custName;
    @Column(name = "cust_source")
    private String custSource;
    @Column(name = "cust_level")
    private String custLevel;
    @Column(name = "cust_industry")
    private String custIndustry;
    @Column(name = "cust_phone")
    private String custPhone;
    @Column(name = "cust_address")
    private String custAddress;

    public Customer() {
    }

    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 getCustLevel() {
        return custLevel;
    }

    public void setCustLevel(String custLevel) {
        this.custLevel = custLevel;
    }

    public String getCustIndustry() {
        return custIndustry;
    }

    public void setCustIndustry(String custIndustry) {
        this.custIndustry = custIndustry;
    }

    public String getCustPhone() {
        return custPhone;
    }

    public void setCustPhone(String custPhone) {
        this.custPhone = custPhone;
    }

    public String getCustAddress() {
        return custAddress;
    }

    public void setCustAddress(String custAddress) {
        this.custAddress = custAddress;
    }

    @Override
    public String toString() {
        return "Customer{" +
                "custId=" + custId +
                ", custName='" + custName + '\'' +
                ", custSource='" + custSource + '\'' +
                ", custLevel='" + custLevel + '\'' +
                ", custIndustry='" + custIndustry + '\'' +
                ", custPhone='" + custPhone + '\'' +
                ", custAddress='" + custAddress + '\'' +
                '}';
    }
}

2、使用Spring Data JPA完成需求

2.1 编写符合Spring Data JPA规范的Dao层接口

/cn/ysk/dao/CustomerDao.java

package cn.ysk.dao;

import cn.ysk.domian.Customer;
import org.springframework.data.jpa.repository.JpaRepository;
import org.springframework.data.jpa.repository.JpaSpecificationExecutor;

/**
 * @Author ysk
 * @Date 2020/3/6 17:21
 * @Version 1.0
 *
 * 符合springDataJPA的dao层规范
 *  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（比如分页）
 *
 */
public interface CustomerDao extends JpaRepository<Customer,Long>, JpaSpecificationExecutor<Customer> {
}

2.2 完成基本的CRUD(增删查改)操作

CustomerTest.java

package cn.ysk.test;

import cn.ysk.dao.CustomerDao;
import cn.ysk.domian.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 sun.rmi.runtime.Log;

import java.util.List;
import java.util.Optional;

/**
 * @Author ysk
 * @Date 2020/3/6 17:28
 * @Version 1.0
 */
@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 CustomerTest {

    @Autowired
    private CustomerDao customerDao;

    /**
     * 根据id查询
     */
    @Test
    public void testFindOne(){
        Optional<Customer> customer =  customerDao.findById((long) 2);
        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id ：保存
     * 如果有id ： 更新
     */
    @Test
    public void testSave(){

        Customer cus = new Customer();
        cus.setCustName("喵喵");
        cus.setCustIndustry("罐头");
        customerDao.save(cus);
    }

    /**
     * 删除
     */
    @Test
    public void testDelete(){
        customerDao.deleteById((long) 3);
    }

    /**
     * 查询所有
     */
    @Test
    public void testFindAll(){
        List<Customer> list = customerDao.findAll();
        for (Object object : list){
            System.out.println(object);
        }

    }
}