jpa+springdata

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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"> 
<context:component-scan base-package="com.atguigu.springdata"></context:component-scan> 
<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> 
</bean> 
<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>



<prop key="hibernate.ejb.naming_strategy">org.hibernate.cfg.ImprovedNamingStrategy</prop>

<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> 
<bean id="transactionManager"
class="org.springframework.orm.jpa.JpaTransactionManager">
<property name="entityManagerFactory" ref="entityManagerFactory"></property>
</bean> 
<tx:annotation-driven transaction-manager="transactionManager"/> 


<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;
} }