spring data jpa之jpql查询

pom.xml

    <properties>
        <spring.version>5.2.14.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>
        <dependency>
            <groupId>org.projectlombok</groupId>
            <artifactId>lombok</artifactId>
            <version>1.18.20</version>
        </dependency>
        <dependency>
            <groupId>junit</groupId>
            <artifactId>junit</artifactId>
            <version>4.13.2</version>
            <scope>test</scope>
        </dependency>
        <dependency>
            <groupId>org.aspectj</groupId>
            <artifactId>aspectjweaver</artifactId>
            <version>1.9.6</version>
        </dependency>
        <dependency>
            <groupId>org.springframework</groupId>
            <artifactId>spring-aop</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>
        <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>5.4.1.Final</version>
        </dependency>
        <dependency>
            <groupId>c3p0</groupId>
            <artifactId>c3p0</artifactId>
            <version>${c3p0.version}</version>
        </dependency>
        <!-- c3p0 end -->

        <dependency>
            <groupId>log4j</groupId>
            <artifactId>log4j</artifactId>
            <version>${log4j.version}</version>
        </dependency>

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


<!--        <dependency>-->
<!--            <groupId>org.slf4j</groupId>-->
<!--            <artifactId>slf4j-log4j12</artifactId>-->
<!--            <version>1.6.6</version>-->
<!--        </dependency>-->

        <dependency>
            <groupId>mysql</groupId>
            <artifactId>mysql-connector-java</artifactId>
            <version>${mysql.version}</version>
        </dependency>
        <!-- spring data jpa 的坐标-->
        <dependency>
            <groupId>org.springframework.data</groupId>
            <artifactId>spring-data-jpa</artifactId>
            <version>2.3.9.RELEASE</version>
        </dependency>


        <dependency>
            <groupId>org.springframework</groupId>
            <artifactId>spring-test</artifactId>
            <version>${spring.version}</version>
        </dependency>

        <!-- el beg 使用spring data jpa 必须引入 -->
        <dependency>
            <groupId>javax.el</groupId>
            <artifactId>javax.el-api</artifactId>
            <version>2.2.5</version>
        </dependency>
        <dependency>
            <groupId>org.glassfish.web</groupId>
            <artifactId>javax.el</artifactId>
            <version>2.2.6</version>
        </dependency>

    </dependencies>

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" 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的配置-->

    <!-- 1.创建entityManagerFactory对象交给spring容器管理-->
    <bean id="entityManagerFactoty" 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="com.qijian.domain" />
        <!-- 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 -->
                <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" />
        </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>
        <property name="password" value="root"></property>
        <property name="jdbcUrl" value="jdbc:mysql:///jpa" ></property>
        <property name="driverClass" value="com.mysql.jdbc.Driver"></property>
    </bean>

    <!--3.整合spring dataJpa
    base-package="com.qijian.dao" 对该包下的接口进行动态代理-->
    <jpa:repositories base-package="com.qijian.dao" transaction-manager-ref="transactionManager"
                      entity-manager-factory-ref="entityManagerFactoty" ></jpa:repositories>

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

    <!-- 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>-->


    <!--5.声明式事务 -->

    <!-- 6. 配置包扫描-->
    <context:component-scan base-package="com.qijian" ></context:component-scan>
</beans>

实体类

package com.qijian.domain;

import lombok.Data;

import javax.persistence.*;

/**
 * TODO 类描述
 *
 * @author qijian.
 * @date 2021/7/26 14:28
 */
@Data
@Entity
@Table(name = "cst_customer")
public class Customer{

    /**
     * 客户主键
     * @Id:申明是主键的配置
     * @GeneratedValue配置主键的生成策略
     *          strategy = GenerationType.IDENTITY:自增
     *              public enum GenerationType{
     *                  TABLE,
     *                  SEQUENCE,
     *                  IDENTITY,
     *                  AUTO
     *             }
     *          JPA提供的四种标准用法为TABLE，SEQUENCE，IDENTITY，AUTO。
     *              a，TABLE：使用一个特定的数据库表格来保存主键。
     *              b，SEQUENCE：根据底层数据库的序列来生成主键，条件是数据库支持序列。
     *              c，IDENTITY：主键由数据库自动生成（主要是自动增长型） mysql数据库
     *              d，AUTO：主键由程序控制
     * @Column:配置属性和字段的映射关系
     *         name:数据库中字段的名称
     *
     */
    @Id
    @GeneratedValue(strategy = GenerationType.IDENTITY)
    @Column(name = "cust_id")
    private Long custId;

    /**
     * 客户姓名
     */
    @Column(name = "cust_name")
    private String custName;

    /**
     * 客户来源
     */
    @Column(name = "cust_source")
    private String custSource;

    /**
     * 客户所属行业
     */
    @Column(name = "cust_industry")
    private String custIndustry;

    /**
     * 客户级别
     */
    @Column(name = "cust_level")
    private String custLevel;

    /**
     * 客户地址
     */
    @Column(name = "cust_address")
    private String custAddress;

    /**
     * 客户联系方式
     */
    @Column(name = "cust_phone")
    private String custPhone;

}

dao层接口

package com.qijian.dao;

import com.qijian.domain.Customer;
import org.springframework.data.jpa.repository.JpaRepository;
import org.springframework.data.jpa.repository.JpaSpecificationExecutor;

/**
 * TODO 符合springdatajpa的dao层接口
 *      JpaRepository<操作实体类型，实体类中主键属性的类型>
 *          封装了基本CRUD操作
 *      JpaSpecificationExecutor<操作的实体类>
 *          封装复杂查询
 *
 * @author qijian.
 * @date 2021/7/26 14:39
 */
public interface CustomerDao extends  JpaRepository<Customer,Long> ,JpaSpecificationExecutor<Customer> {

}

测试类

package com.qijian.dao;

import com.qijian.dao.CustomerDao;
import com.qijian.domain.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 org.springframework.transaction.annotation.Transactional;

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

/**
 * TODO 类描述
 *
 * @author qijian.
 * @date 2021/7/26 14:54
 */
@RunWith(SpringJUnit4ClassRunner.class)//声明spring提供的单元测试
@ContextConfiguration(locations = "classpath:applicationContext.xml")//指定spring容器的配置信息
public class TestDao {

    @Autowired
    private CustomerDao customerDao;

    @Test
    @Transactional
    public void testFindOne(){
//        Optional<Customer> byId = customerDao.findById(2l);
//        System.out.println(byId);

//        使用下面的方法获取报错
//          org.hibernate.LazyInitializationException: could not initialize proxy - no Session
//        目前还没有找到解决方法
        Customer customer = customerDao.getOne(3l);
        System.out.println(customer);
    }
    @Test
    public void test1(){
        List list = customerDao.findAll();
        for (Object o:list ) {
            System.out.println(o);
        }
    }

    /**
     * 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主键属性：保存
     *      存在id主键属性，根据id查询数据，更新数据
     */
    @Test
    public void testSave(){
        Customer customer = new Customer();
        customer.setCustId(9l);
        customer.setCustName("qijian");
        customer.setCustPhone("11111111");
        customerDao.save(customer);
    }

    @Test
    public void testDelete(){
        Customer customer = new Customer();
        customer.setCustId(10l);
        customer.setCustName("qijian");
        customer.setCustPhone("11111111");
        customerDao.delete(customer);

        customerDao.deleteById(2l);
    }

    /**测试统计查询**/
    @Test
    public void testCount(){
        long count = customerDao.count();
        System.out.println(count);
    }

    /**
     * 判断id为固定值的客户是否存在
     *
     */
    @Test
    public void testExists(){
        boolean exists = customerDao.existsById(4l);
        System.out.println(exists);
        Integer d;
    }

    /**
     * 根据id查询
     * @Transactional : 保证getOne正常运行
     *  findOne()
     *      em.find()   立即加载
     *  getOne()
     *      em.getReference()   延迟加载
     *      返回的是一个客户的动态代理对象
     *      什么时候用，什么时候查询
     */
    @Test
    @Transactional
    public void testGetone(){
//        getOne() 使用em.getReference(getDomainClass(), id);实现延迟加载
        Customer customer = customerDao.getOne(4l);
        System.out.println(customer);
    }

}