三、Spring Data JPA入门案例

创建Maven工程

导入坐标

<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>4.0.0modelVersion>

    <groupId>cn.itcastgroupId>
    <artifactId>jpa-day2artifactId>
    <version>1.0-SNAPSHOTversion>

    <properties>
        <spring.version>5.0.2.RELEASEspring.version>
        <hibernate.version>5.0.7.Finalhibernate.version>
        <slf4j.version>1.6.6slf4j.version>
        <log4j.version>1.2.12log4j.version>
        <c3p0.version>0.9.1.2c3p0.version>
        <mysql.version>5.1.6mysql.version>
    properties>

    <dependencies>
        
        <dependency>
            <groupId>junitgroupId>
            <artifactId>junitartifactId>
            <version>4.12version>
            <scope>testscope>
        dependency>
        
        <dependency>
            <groupId>org.aspectjgroupId>
            <artifactId>aspectjweaverartifactId>
            <version>1.6.8version>
        dependency>

        <dependency>
            <groupId>org.springframeworkgroupId>
            <artifactId>spring-aopartifactId>
            <version>${spring.version}version>
        dependency>

        <dependency>
            <groupId>org.springframeworkgroupId>
            <artifactId>spring-contextartifactId>
            <version>${spring.version}version>
        dependency>

        <dependency>
            <groupId>org.springframeworkgroupId>
            <artifactId>spring-context-supportartifactId>
            <version>${spring.version}version>
        dependency>
        
        <dependency>
            <groupId>org.springframeworkgroupId>
            <artifactId>spring-ormartifactId>
            <version>${spring.version}version>
        dependency>

        <dependency>
            <groupId>org.springframeworkgroupId>
            <artifactId>spring-beansartifactId>
            <version>${spring.version}version>
        dependency>

        <dependency>
            <groupId>org.springframeworkgroupId>
            <artifactId>spring-coreartifactId>
            <version>${spring.version}version>
        dependency>
        
        
        <dependency>
            <groupId>org.hibernategroupId>
            <artifactId>hibernate-coreartifactId>
            <version>${hibernate.version}version>
        dependency>
        <dependency>
            <groupId>org.hibernategroupId>
            <artifactId>hibernate-entitymanagerartifactId>
            <version>${hibernate.version}version>
        dependency>
        <dependency>
            <groupId>org.hibernategroupId>
            <artifactId>hibernate-validatorartifactId>
            <version>5.2.1.Finalversion>
        dependency>
        

        
        <dependency>
            <groupId>c3p0groupId>
            <artifactId>c3p0artifactId>
            <version>${c3p0.version}version>
        dependency>
        

        
        <dependency>
            <groupId>log4jgroupId>
            <artifactId>log4jartifactId>
            <version>${log4j.version}version>
        dependency>

        <dependency>
            <groupId>org.slf4jgroupId>
            <artifactId>slf4j-apiartifactId>
            <version>${slf4j.version}version>
        dependency>

        <dependency>
            <groupId>org.slf4jgroupId>
            <artifactId>slf4j-log4j12artifactId>
            <version>${slf4j.version}version>
        dependency>
        
        <dependency>
            <groupId>mysqlgroupId>
            <artifactId>mysql-connector-javaartifactId>
            <version>${mysql.version}version>
        dependency>
        
        <dependency>
            <groupId>org.springframework.datagroupId>
            <artifactId>spring-data-jpaartifactId>
            <version>1.9.0.RELEASEversion>
        dependency>

        <dependency>
            <groupId>org.springframeworkgroupId>
            <artifactId>spring-testartifactId>
            <version>${spring.version}version>
        dependency>
        
        <dependency>
            <groupId>javax.elgroupId>
            <artifactId>javax.el-apiartifactId>
            <version>2.2.4version>
        dependency>
        <dependency>
            <groupId>org.glassfish.webgroupId>
            <artifactId>javax.elartifactId>
            <version>2.2.4version>
        dependency>
        
    dependencies>

project>

创建实体类，使用Jpa注解

@Entity
@Table(name="cst_customer")
public class Customer {

    @Id
    @GeneratedValue(strategy = GenerationType.IDENTITY)
    @Column(name="cust_id")
    private Long custId;
    @Column(name="cust_address")
    private String custAddress;
    @Column(name="cust_industry")
    private String custIndustry;
    @Column(name="cust_level")
    private String custLevel;
    @Column(name="cust_name")
    private String custName;
    @Column(name="cust_phone")
    private String custPhone;
    @Column(name="cust_source")
    private String custSource;
	//getter and setter
    @Override
    public String toString() {
        return "Customer{" +
                "custId=" + custId +
                ", custAddress='" + custAddress + '\'' +
                ", custIndustry='" + custIndustry + '\'' +
                ", custLevel='" + custLevel + '\'' +
                ", custName='" + custName + '\'' +
                ", custPhone='" + custPhone + '\'' +
                ", custSource='" + custSource + '\'' +
                '}';
    }
}

Dao接口：

/**
 * 符合SpringDataJpa的dao层接口规范
 *      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CRUD操作
 *      JpaSpecificationExecutor<操作的实体类类型>           封装了复杂查询（分页）
 */
public interface CustomerDao extends JpaRepository<Customer,Long> ,JpaSpecificationExecutor<Customer> {
}

创建Spring的配置文件：

<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">

    

    
    <bean id="entityManagerFactory" class="org.springframework.orm.jpa.LocalContainerEntityManagerFactoryBean">
        <property name="dataSource" ref="dataSource" />

        
        <property name="packagesToScan" value="com.liaoxiang.domain" />

        
        <property name="persistenceProvider">
            <bean class="org.hibernate.jpa.HibernatePersistenceProvider"/>
        property>

        
        <property name="jpaVendorAdapter">
            <bean class="org.springframework.orm.jpa.vendor.HibernateJpaVendorAdapter">
                
                <property name="generateDdl" value="false" />
                
                <property name="database" value="MYSQL" />
                
                <property name="databasePlatform" value="org.hibernate.dialect.MySQLDialect" />
                
                <property name="showSql" value="true" />
            bean>
        property>

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

    bean>

    
    <bean id="dataSource" class="com.mchange.v2.c3p0.ComboPooledDataSource">
        <property name="user" value="root">property>
        <property name="password" value="123456">property>
        <property name="jdbcUrl" value="jdbc:mysql:///jpa" >property>
        <property name="driverClass" value="com.mysql.jdbc.Driver">property>
    bean>

    
    <jpa:repositories base-package="com.liaoxiang.dao"
                      transaction-manager-ref="transactionManager"
                      entity-manager-factory-ref="entityManagerFactory" >
    jpa:repositories>

    
    
    <bean id="transactionManager" class="org.springframework.orm.jpa.JpaTransactionManager">
        <property name="entityManagerFactory" ref="entityManagerFactory">property>
    bean>

    
    <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>

    
    <aop:config>
        <aop:pointcut id="pointcut" expression="execution(* com.liaoxiang.service.*.*(..))" />
        <aop:advisor advice-ref="txAdvice" pointcut-ref="pointcut" />
    aop:config>

    
    <context:component-scan base-package="com.liaoxiang" >context:component-scan>
beans>

使用JpaRepository和JpaSpecificationExecutor接口里提供的方法进行简单CRUD测试

@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 CustomerDaoTest {

    @Autowired
    private CustomerDao customerDao;

    /**
     * 根据id查询
     */
    @Test
    public void testFindOne() {
        Customer customer = customerDao.findOne(4l);
        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主键属性：保存
     *       存在id主键属性，根据id 更新数据
     */
    @Test
    public void testSave() {
        Customer customer  = new Customer();
        customer.setCustName("中国移动");
        customer.setCustLevel("vip");
        customer.setCustIndustry("通信");
        customerDao.save(customer);
    }
    @Test
    public void testUpdate() {
        Customer customer  = new Customer();
        customer.setCustId(7l);
        customer.setCustName("中国联通");
        customerDao.save(customer);
    }
    @Test
    public void testDelete () {
        customerDao.delete(3l);
    }
    /**
     * 查询所有
     */
    @Test
    public void testFindAll() {
        List<Customer> list = customerDao.findAll();
        for(Customer customer : list) {
            System.out.println(customer);
        }
    }
    /**
     * 测试统计查询：查询客户的总数量
     *      count:统计总条数
     */
    @Test
    public void testCount() {
        long count = customerDao.count();//查询全部的客户数量
        System.out.println(count);
    }

    /**
     * 测试：判断id为4的客户是否存在
     *      1. 可以查询以下id为4的客户
     *          如果值为空，代表不存在，如果不为空，代表存在
     *      2. 判断数据库中id为4的客户的数量
     *          如果数量为0，代表不存在，如果大于0，代表存在
     */
    @Test
    public void  testExists() {
        boolean exists = customerDao.exists(4l);
        System.out.println("id为4的客户 是否存在："+exists);
    }
    /**
     * 根据id从数据库查询
     *      @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,要打印的时候才发送sql语句去查询
     */
    @Test
    @Transactional
    public void  testGetOne() {
        Customer customer = customerDao.getOne(4l);
        System.out.println(customer);
    }
}

使用JPQL、Sql、方法名称规则查询
在Dao接口中定义方法：

public interface CustomerDao extends JpaRepository<Customer,Long> ,JpaSpecificationExecutor<Customer> {

    /**
     * 案例：根据客户名称查询客户
     *      使用jpql的形式查询
     *  jpql：from Customer where custName = ?
     *  配置jpql语句，使用的@Query注解
     */
    @Query(value="from Customer where custName = ?1")
    Customer findJpql(String custName);

    /**
     * 案例：根据客户名称和客户id查询客户
     *      jpql： from Customer where custName = ? and custId = ?
     *  对于多个占位符参数
     *      赋值的时候，默认的情况下，占位符的位置需要和方法参数中的位置保持一致
     *  可以指定占位符参数的位置
     *      ? 索引的方式，指定此占位的取值来源
     */
    @Query(value = "from Customer where custName = ?2 and custId = ?1")
    Customer findCustNameAndId(Long id,String name);

    /**
     * 使用jpql完成更新操作
     *      案例 ： 根据id更新，客户的名称
     *          更新4号客户的名称，将名称改为“腾讯”
     *
     *  sql:  update cst_customer set cust_name = ? where cust_id = ?
     *  jpql: update Customer set custName = ? where custId = ?
     *
     *  @Query:     代表的是进行查询,声明此方法是用来进行更新操作
     *  @Modifying: 当前执行的是一个更新操作
     *
     */
    @Query(value = " update Customer set custName = ?2 where custId = ?1 ")
    @Modifying
    void updateCustomer(long custId,String custName);

    /**
     * 使用sql的形式查询：
     *     查询全部的客户
     *  sql:   select * from cst_customer;
     *  Query: 配置sql查询
     *      1、value ：       sql语句
     *      2、nativeQuery ： 查询方式
     *                true： sql查询
     *               false： jpql查询
     */
    //@Query(value = " select * from cst_customer" ,nativeQuery = true)
    @Query(value="select * from cst_customer where cust_name like ?1",nativeQuery = true)
    List<Object [] > findSql(String name);

    /**
     * 方法名的约定：findByXxx
     *  findByCustName  --  根据客户名称查询
     *
     *  在springDataJpa的运行阶段
     *          会根据方法名称进行解析  findBy    from  xxx(实体类)
     *                                      属性名称      where  custName =
     *      1.findBy  + 属性名称 （根据属性名称进行完成匹配的查询=）
     *      2.findBy  + 属性名称 + “查询方式（Like, isnull...）”
     *          findByCustNameLike
     *      3.多条件查询
     *          findBy + 属性名 + “查询方式”   + “多条件的连接符（and|or）”  + 属性名 + “查询方式”
     */
    Customer findByCustName(String custName);

    List<Customer> findByCustNameLike(String custName);

    //使用客户名称模糊匹配和客户所属行业精准匹配的查询
    Customer findByCustNameLikeAndCustIndustry(String custName,String custIndustry);
}

测试方法

@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 JpqlTest {
    @Autowired
    private CustomerDao customerDao;

    @Test
    public void  testFindJPQL() {
        Customer customer = customerDao.findJpql("美团");
        System.out.println(customer);
    }
    @Test
    public void testFindCustNameAndId() {
       // Customer customer =  customerDao.findCustNameAndId("百度",2l);
        Customer customer =  customerDao.findCustNameAndId(5l,"华为");
        System.out.println(customer);
    }
    /**
     * 测试jpql的更新操作
     *  * springDataJpa中使用jpql完成 更新/删除操作
     *         * 需要手动添加事务的支持
     *         * 默认会执行结束之后，回滚事务
     *   @Rollback : 设置是否自动回滚
     *               false | true
     */
    @Test
    @Transactional //添加事务的支持
    @Rollback(value = false)
    public void testUpdateCustomer() {
        customerDao.updateCustomer(4l,"腾讯");
    }

    //使用sql语句模糊查询
    @Test
    public void testFindSql() {
        List<Object[]> list = customerDao.findSql("%国%");
        for(Object [] obj : list) {
            System.out.println(Arrays.toString(obj));
        }
    }
    //测试方法命名规则的查询
    @Test
    public void testNaming() {
        Customer customer = customerDao.findByCustName("华为");
        System.out.println(customer);
    }
    //测试方法命名规则的查询
    @Test
    public void testFindByCustNameLike() {
        List<Customer> list = customerDao.findByCustNameLike("%美%");
        for (Customer customer : list) {
            System.out.println(customer);
        }
    }
    //测试方法命名规则的查询
    @Test
    public void testFindByCustNameLikeAndCustIndustry() {
        Customer customer = customerDao.findByCustNameLikeAndCustIndustry("新%", "教育");
        System.out.println(customer);
    }
}