jpa+springdata

学习爱酷学习网尚硅谷springdata笔记：

1.在 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:context="http://www.springframework.org/schema/context"
     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/data/jpa http://www.springframework.org/schema/data/jpa/spring-jpa-1.3.xsd
         http://www.springframework.org/schema/tx http://www.springframework.org/schema/tx/spring-tx-4.0.xsd
         http://www.springframework.org/schema/context http://www.springframework.org/schema/context/spring-context-4.0.xsd">

     <!-- 配置自动扫描的包 -->
     <context:component-scan base-package="com.atguigu.springdata"></context:component-scan>

     <!-- 1. 配置数据源 -->
     <context:property-placeholder location="classpath:db.properties"/>

     <bean id="dataSource"
         class="com.mchange.v2.c3p0.ComboPooledDataSource">
         <property name="user" value="${jdbc.user}"></property>
         <property name="password" value="${jdbc.password}"></property>
         <property name="driverClass" value="${jdbc.driverClass}"></property>
         <property name="jdbcUrl" value="${jdbc.jdbcUrl}"></property>

         <!-- 配置其他属性 -->
     </bean>

     <!-- 2. 配置 JPA 的 EntityManagerFactory -->
     <bean id="entityManagerFactory"
         class="org.springframework.orm.jpa.LocalContainerEntityManagerFactoryBean">
         <property name="dataSource" ref="dataSource"></property>
         <property name="jpaVendorAdapter">
             <bean class="org.springframework.orm.jpa.vendor.HibernateJpaVendorAdapter"></bean>
         </property>
         <property name="packagesToScan" value="com.atguigu.springdata"></property>
         <property name="jpaProperties">
             <props>
                 <!-- 二级缓存相关 -->
                 <!--
                 <prop key="hibernate.cache.region.factory_class">org.hibernate.cache.ehcache.EhCacheRegionFactory</prop>
                 <prop key="net.sf.ehcache.configurationResourceName">ehcache-hibernate.xml</prop>
                 -->
                 <!-- 生成的数据表的列的映射策略 -->
                 <prop key="hibernate.ejb.naming_strategy">org.hibernate.cfg.ImprovedNamingStrategy</prop>
                 <!-- hibernate 基本属性 -->
                 <prop key="hibernate.dialect">org.hibernate.dialect.MySQL5InnoDBDialect</prop>
                 <prop key="hibernate.show_sql">true</prop>
                 <prop key="hibernate.format_sql">true</prop>
                 <prop key="hibernate.hbm2ddl.auto">update</prop>
             </props>
         </property>
     </bean>

     <!-- 3. 配置事务管理器 -->
     <bean id="transactionManager"
         class="org.springframework.orm.jpa.JpaTransactionManager">
         <property name="entityManagerFactory" ref="entityManagerFactory"></property>
     </bean>

     <!-- 4. 配置支持注解的事务 -->
     <tx:annotation-driven transaction-manager="transactionManager"/>

     <!-- 5. 配置 SpringData -->
     <!-- 加入  jpa 的命名空间 -->
     <!-- base-package: 扫描 Repository Bean 所在的 package -->
     <jpa:repositories base-package="com.atguigu.springdata"
         entity-manager-factory-ref="entityManagerFactory"></jpa:repositories>

 </beans>

其中db.properties

 jdbc.user=root
 jdbc.password=1111
 jdbc.driverClass=com.mysql.jdbc.Driver
 jdbc.jdbcUrl=jdbc:mysql://localhost:3306/springdata

测试类：

 package com.atguigu.springdata.test;

 import java.io.FileNotFoundException;
 import java.io.IOException;
 import java.sql.SQLException;
 import java.util.ArrayList;
 import java.util.Arrays;
 import java.util.Date;
 import java.util.List;

 import javax.persistence.criteria.CriteriaBuilder;
 import javax.persistence.criteria.CriteriaQuery;
 import javax.persistence.criteria.Path;
 import javax.persistence.criteria.Predicate;
 import javax.persistence.criteria.Root;
 import javax.sql.DataSource;

 import org.junit.Test;
 import org.springframework.context.ApplicationContext;
 import org.springframework.context.support.ClassPathXmlApplicationContext;
 import org.springframework.data.domain.Page;
 import org.springframework.data.domain.PageRequest;
 import org.springframework.data.domain.Sort;
 import org.springframework.data.domain.Sort.Direction;
 import org.springframework.data.domain.Sort.Order;
 import org.springframework.data.jpa.domain.Specification;

 import com.atguigu.springdata.Person;
 import com.atguigu.springdata.PersonRepsotory;
 import com.atguigu.springdata.PersonService;
 import com.atguigu.springdata.commonrepositorymethod.AddressRepository;

 public class SpringDataTest {

     private ApplicationContext ctx = null;
     private PersonRepsotory personRepsotory = null;
     private PersonService personService;

     {
         ctx = new ClassPathXmlApplicationContext("applicationContext.xml");
         personRepsotory = ctx.getBean(PersonRepsotory.class);
         personService = ctx.getBean(PersonService.class);
     }

     //使用自定义的方法，需要声明接口，并继承，同时完成实现类，此方法比较少用
     @Test
     public void testCustomRepositoryMethod(){
         personRepsotory.test();
     }

     /**
      * 目标: 实现带查询条件的分页. id > 5 的条件
      *
      * 调用 JpaSpecificationExecutor 的 Page<T> findAll(Specification<T> spec, Pageable pageable);
      * Specification: 封装了 JPA Criteria 查询的查询条件
      * Pageable: 封装了请求分页的信息: 例如 pageNo, pageSize, Sort
      */
     //使用继承JpaSpecificationExecutor的方法实现条件查询+分页
     @Test
     public void testJpaSpecificationExecutor(){
         int pageNo = 3 - 1;
         int pageSize = 5;
         PageRequest pageable = new PageRequest(pageNo, pageSize);

         //通常使用 Specification 的匿名内部类
         Specification<Person> specification = new Specification<Person>() {
             /**
              * @param *root: 代表查询的实体类.
              * @param query: 可以从中可到 Root 对象, 即告知 JPA Criteria 查询要查询哪一个实体类. 还可以
              * 来添加查询条件, 还可以结合 EntityManager 对象得到最终查询的 TypedQuery 对象.
              * @param *cb: CriteriaBuilder 对象. 用于创建 Criteria 相关对象的工厂. 当然可以从中获取到 Predicate 对象
              * @return: *Predicate 类型, 代表一个查询条件.
              */
             @Override
             public Predicate toPredicate(Root<Person> root,
                     CriteriaQuery<?> query, CriteriaBuilder cb) {
                 Path path = root.get("id");
                 Predicate predicate = cb.gt(path, 5);
                 return predicate;
             }
         };

         Page<Person> page = personRepsotory.findAll(specification, pageable);

         System.out.println("总记录数: " + page.getTotalElements());
         System.out.println("当前第几页: " + (page.getNumber() + 1));
         System.out.println("总页数: " + page.getTotalPages());
         System.out.println("当前页面的 List: " + page.getContent());
         System.out.println("当前页面的记录数: " + page.getNumberOfElements());
     }

     //使用继承JpaRepository的方法
     @Test
     public void testJpaRepository(){
         Person person = new Person();
         person.setBirth(new Date());
         person.setEmail("xy@atguigu.com");
         person.setLastName("xyz");
         person.setId(28);

         Person person2 = personRepsotory.saveAndFlush(person);

         System.out.println(person == person2);
     }

     //使用继承PagingAndSortingRespository的方法，实现分页
     @Test
     public void testPagingAndSortingRespository(){
         //pageNo 从 0 开始.
         int pageNo = 6 - 1;
         int pageSize = 5;
         //Pageable 接口通常使用的其 PageRequest 实现类. 其中封装了需要分页的信息
         //排序相关的. Sort 封装了排序的信息
         //Order 是具体针对于某一个属性进行升序还是降序.
         Order order1 = new Order(Direction.DESC, "id");
         Order order2 = new Order(Direction.ASC, "email");
         Sort sort = new Sort(order1, order2);

         PageRequest pageable = new PageRequest(pageNo, pageSize, sort);
         Page<Person> page = personRepsotory.findAll(pageable);

         System.out.println("总记录数: " + page.getTotalElements());
         System.out.println("当前第几页: " + (page.getNumber() + 1));
         System.out.println("总页数: " + page.getTotalPages());
         System.out.println("当前页面的 List: " + page.getContent());
         System.out.println("当前页面的记录数: " + page.getNumberOfElements());
     }

     //使用继承CrudReposiory的方法
     @Test
     public void testCrudReposiory(){
         List<Person> persons = new ArrayList<>();

         for(int i = 'a'; i <= 'z'; i++){
             Person person = new Person();
             person.setAddressId(i + 1);
             person.setBirth(new Date());
             person.setEmail((char)i + "" + (char)i + "@atguigu.com");
             person.setLastName((char)i + "" + (char)i);

             persons.add(person);
         }

         personService.savePersons(persons);
     }

     @Test
     public void testModifying(){
 //        personRepsotory.updatePersonEmail(1, "mmmm@atguigu.com");
         personService.updatePersonEmail("mmmm@atguigu.com", 1);
     }

     //设置 nativeQuery=true 即可以使用原生的 SQL 查询
     @Test
     public void testNativeQuery(){
         long count = personRepsotory.getTotalCount();
         System.out.println(count);
     }

     //使用 @Query 几种传递参数的方式
     @Test
     public void testQueryAnnotationLikeParam(){
 //        List<Person> persons = personRepsotory.testQueryAnnotationLikeParam("%A%", "%bb%");
 //        System.out.println(persons.size());

 //        List<Person> persons = personRepsotory.testQueryAnnotationLikeParam("A", "bb");
 //        System.out.println(persons.size());

         List<Person> persons = personRepsotory.testQueryAnnotationLikeParam2("bb", "A");
         System.out.println(persons.size());
     }

     @Test
     public void testQueryAnnotationParams2(){
         List<Person> persons = personRepsotory.testQueryAnnotationParams2("aa@atguigu.com", "AA");
         System.out.println(persons);
     }

     @Test
     public void testQueryAnnotationParams1(){
         List<Person> persons = personRepsotory.testQueryAnnotationParams1("AA", "aa@atguigu.com");
         System.out.println(persons);
     }

     //使用 @Query 注解可以自定义 JPQL 语句以实现更灵活的查询
     @Test
     public void testQueryAnnotation(){
         Person person = personRepsotory.getMaxIdPerson();
         System.out.println(person);
     }

     //根据外键条件查询，注意下划线的使用，若无下滑线，将优先获取person的属性,下滑线则表示为外键
     @Test
     public void testKeyWords2(){
         List<Person> persons = personRepsotory.getByAddress_IdGreaterThan(1);
         System.out.println(persons);
     }

     //几种条件查询的例子
     @Test
     public void testKeyWords(){
         List<Person> persons = personRepsotory.getByLastNameStartingWithAndIdLessThan("X", 10);
         System.out.println(persons);

         persons = personRepsotory.getByLastNameEndingWithAndIdLessThan("X", 10);
         System.out.println(persons);

         persons = personRepsotory.getByEmailInAndBirthLessThan(Arrays.asList("AA@atguigu.com", "FF@atguigu.com",
                 "SS@atguigu.com"), new Date());
         System.out.println(persons.size());
     }

     //获取lastname为AA的person
     @Test
     public void testHelloWorldSpringData() throws FileNotFoundException, IOException, InstantiationException, IllegalAccessException{
         System.out.println(personRepsotory.getClass().getName());
         Person person = personRepsotory.getByLastName("AA");
         System.out.println(person);
     }

     //验证数据库连接是否成功
     @Test
     public void testDataSource() throws SQLException {
         DataSource dataSource = ctx.getBean(DataSource.class);
         System.out.println(dataSource.getConnection());
     }

 }

持久层类：

 package com.atguigu.springdata;

 import java.util.Date;
 import java.util.List;

 import org.springframework.data.jpa.repository.JpaRepository;
 import org.springframework.data.jpa.repository.JpaSpecificationExecutor;
 import org.springframework.data.jpa.repository.Modifying;
 import org.springframework.data.jpa.repository.Query;
 import org.springframework.data.repository.query.Param;

 /**
  * 1. Repository 是一个空接口. 即是一个标记接口
  * 2. 若我们定义的接口继承了 Repository, 则该接口会被 IOC 容器识别为一个 Repository Bean.
  * 纳入到 IOC 容器中. 进而可以在该接口中定义满足一定规范的方法.
  *
  * 3. 实际上, 也可以通过 @RepositoryDefinition 注解来替代继承 Repository 接口
  */
 /**
  * 在 Repository 子接口中声明方法
  * 1. 不是随便声明的. 而需要符合一定的规范
  * 2. 查询方法以 find | read | get 开头
  * 3. 涉及条件查询时，条件的属性用条件关键字连接
  * 4. 要注意的是：条件属性以首字母大写。
  * 5. 支持属性的级联查询. 若当前类有符合条件的属性, 则优先使用, 而不使用级联属性.
  * 若需要使用级联属性, 则属性之间使用 _ 进行连接.
  */
 //@RepositoryDefinition(domainClass=Person.class,idClass=Integer.class)
 public interface PersonRepsotory extends
     JpaRepository<Person, Integer>,
     JpaSpecificationExecutor<Person>, PersonDao{

     //根据 lastName 来获取对应的 Person
     Person getByLastName(String lastName);

     //WHERE lastName LIKE ?% AND id < ?
     List<Person> getByLastNameStartingWithAndIdLessThan(String lastName, Integer id);

     //WHERE lastName LIKE %? AND id < ?
     List<Person> getByLastNameEndingWithAndIdLessThan(String lastName, Integer id);

     //WHERE email IN (?, ?, ?) OR birth < ?
     List<Person> getByEmailInAndBirthLessThan(List<String> emails, Date birth);

     //WHERE a.id > ?
     List<Person> getByAddress_IdGreaterThan(Integer id);

     //查询 id 值最大的那个 Person
     //使用 @Query 注解可以自定义 JPQL 语句以实现更灵活的查询
     @Query("SELECT p FROM Person p WHERE p.id = (SELECT max(p2.id) FROM Person p2)")
     Person getMaxIdPerson();

     //为 @Query 注解传递参数的方式1: 使用占位符.
     @Query("SELECT p FROM Person p WHERE p.lastName = ?1 AND p.email = ?2")
     List<Person> testQueryAnnotationParams1(String lastName, String email);

     //为 @Query 注解传递参数的方式1: 命名参数的方式.
     @Query("SELECT p FROM Person p WHERE p.lastName = :lastName AND p.email = :email")
     List<Person> testQueryAnnotationParams2(@Param("email") String email, @Param("lastName") String lastName);

     //SpringData 允许在占位符上添加 %%.
     @Query("SELECT p FROM Person p WHERE p.lastName LIKE %?1% OR p.email LIKE %?2%")
     List<Person> testQueryAnnotationLikeParam(String lastName, String email);

     //SpringData 允许在占位符上添加 %%.
     @Query("SELECT p FROM Person p WHERE p.lastName LIKE %:lastName% OR p.email LIKE %:email%")
     List<Person> testQueryAnnotationLikeParam2(@Param("email") String email, @Param("lastName") String lastName);

     //设置 nativeQuery=true 即可以使用原生的 SQL 查询
     @Query(value="SELECT count(id) FROM jpa_persons", nativeQuery=true)
     long getTotalCount();

     //可以通过自定义的 JPQL 完成 UPDATE 和 DELETE 操作. 注意: JPQL 不支持使用 INSERT
     //在 @Query 注解中编写 JPQL 语句, 但必须使用 @Modifying 进行修饰. 以通知 SpringData, 这是一个 UPDATE 或 DELETE 操作
     //UPDATE 或 DELETE 操作需要使用事务, 此时需要定义 Service 层. 在 Service 层的方法上添加事务操作.
     //默认情况下, SpringData 的每个方法上有事务, 但都是一个只读事务. 他们不能完成修改操作!
     @Modifying
     @Query("UPDATE Person p SET p.email = :email WHERE id = :id")
     void updatePersonEmail(@Param("id") Integer id, @Param("email") String email);
 }
  

自定义方法时，声明的接口：

 package com.atguigu.springdata;

 public interface PersonDao {

     void test();

 }

其实现类：使用原生entityManager

 package com.atguigu.springdata;

 import javax.persistence.EntityManager;
 import javax.persistence.PersistenceContext;

 public class PersonRepsotoryImpl implements PersonDao {

     @PersistenceContext
     private EntityManager entityManager;

     @Override
     public void test() {
         Person person = entityManager.find(Person.class, 11);
         System.out.println("-->" + person);
     }

 }

PersonService:用于测试需要事务包裹的方法

 package com.atguigu.springdata;

 import java.util.List;

 import org.springframework.beans.factory.annotation.Autowired;
 import org.springframework.stereotype.Service;
 import org.springframework.transaction.annotation.Transactional;

 @Service
 public class PersonService {

     @Autowired
     private PersonRepsotory personRepsotory;

     @Transactional
     public void savePersons(List<Person> persons){
         personRepsotory.save(persons);
     }

     @Transactional
     public void updatePersonEmail(String email, Integer id){
         personRepsotory.updatePersonEmail(id, email);
     }
 }

与数据库表单对应的实体类：

 package com.atguigu.springdata;

 import java.util.Date;

 import javax.persistence.Column;
 import javax.persistence.Entity;
 import javax.persistence.GeneratedValue;
 import javax.persistence.Id;
 import javax.persistence.JoinColumn;
 import javax.persistence.ManyToOne;
 import javax.persistence.Table;

 @Table(name="JPA_PERSONS")
 @Entity
 public class Person {

     private Integer id;
     private String lastName;

     private String email;
     private Date birth;

     private Address address;

     private Integer addressId;

     @GeneratedValue
     @Id
     public Integer getId() {
         return id;
     }

     public void setId(Integer id) {
         this.id = id;
     }

     public String getLastName() {
         return lastName;
     }

     public void setLastName(String lastName) {
         this.lastName = lastName;
     }

     public String getEmail() {
         return email;
     }

     public void setEmail(String email) {
         this.email = email;
     }

     public Date getBirth() {
         return birth;
     }

     public void setBirth(Date birth) {
         this.birth = birth;
     }

     @Column(name="ADD_ID")
     public Integer getAddressId() {
         return addressId;
     }

     public void setAddressId(Integer addressId) {
         this.addressId = addressId;
     }

     @JoinColumn(name="ADDRESS_ID")
     @ManyToOne
     public Address getAddress() {
         return address;
     }

     public void setAddress(Address address) {
         this.address = address;
     }

     @Override
     public String toString() {
         return "Person [id=" + id + ", lastName=" + lastName + ", email="
                 + email + ", brith=" + birth + "]";
     }
 }

 package com.atguigu.springdata;

 import javax.persistence.Entity;
 import javax.persistence.GeneratedValue;
 import javax.persistence.Id;
 import javax.persistence.Table;

 @Table(name="JPA_ADDRESSES")
 @Entity
 public class Address {

     private Integer id;
     private String province;
     private String city;

     @GeneratedValue
     @Id
     public Integer getId() {
         return id;
     }

     public void setId(Integer id) {
         this.id = id;
     }

     public String getProvince() {
         return province;
     }

     public void setProvince(String province) {
         this.province = province;
     }

     public String getCity() {
         return city;
     }

     public void setCity(String city) {
         this.city = city;
     }

 }

使用的jar包：

项目结构：

补充：