Spring Data下---Spring Data JPA的使用

Spring JPA · 發表 2019-03-15 22:51:48

摘要： Spring Data下---Spring Data JPA的使用一、SpringData的環境搭建依賴新增： <dependency> <groupId>org.springframework</groupId> <a...

Spring Data下---Spring Data JPA的使用

一、SpringData的環境搭建

依賴新增：

<dependency>
<groupId>org.springframework</groupId>
<artifactId>spring-jdbc</artifactId>
<version>4.3.5.RELEASE</version>
</dependency>
<dependency>
<groupId>org.springframework</groupId>
<artifactId>spring-context</artifactId>
<version>4.2.0.RELEASE</version>
</dependency>

beans.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: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">


<!--1.配置資料來源-->
<bean id="dataSource" class="org.springframework.jdbc.datasource.DriverManagerDataSource">
<property name="driverClassName" value="com.mysql.jdbc.Driver"/>
<property name="username" value="root"/>
<property name="password" value="root"/>
<property name="url" value="jdbc:mysql://localhost:3306/spring_data"/>
</bean>

<!--2.配置EntityManagerFactory-->
<bean id="entityManagerFactory" class="org.springframework.orm.jpa.LocalContainerEntityManagerFactoryBean">
<property name="dataSource" ref="dataSource"/>
<property name="jpaVendorAdapter">
<bean class="org.springframework.orm.jpa.vendor.HibernateJpaVendorAdapter"/>
</property>
<property name="packagesToScan" value="com.hcx"/>
<property name="jpaProperties">
<props>
<prop key="hibernate.ejb.naming_strategy">org.hibernate.cfg.ImprovedNamingStrategy</prop>
<!--方言-->
<prop key="hibernate.dialect">org.hibernate.dialect.MySQL5InnoDBDialect</prop>
<!--執行時顯示sql-->
<prop key="hibernate.show_sql">true</prop>
<!--格式化sql-->
<prop key="hibernate.format_sql">true</prop>
<!--自動建立表：根據實體建立表-->
<prop key="hibernate.hbm2ddl.auto">update</prop>
</props>
</property>
</bean>

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

<!--4.支援註解的事務-->
<tx:annotation-driven transaction-manager="transactionManager"/>

<!--5.配置spring data-->
<jpa:repositories base-package="com.hcx" entity-manager-factory-ref="entityManagerFactory"/>

<context:component-scan base-package="com.hcx"/>

</beans>

Employee:

package com.hcx.domain;

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

/**
 * 僱員:開發實體類，通過實體類自動生成資料表
 * Created by HCX on 2019/3/11.
 */
@Entity
public class Employee {

private Integer id;

private String name;

private Integer age;

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

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

@Column(length = 20) //設定該欄位的長度
public String getName() {
return name;
}

public void setName(String name) {
this.name = name;
}

public Integer getAge() {
return age;
}

public void setAge(Integer age) {
this.age = age;
}
}

repository:

package com.hcx.repository;

import com.hcx.domain.Employee;
import org.springframework.data.repository.Repository;


/**
 * Created by HCX on 2019/3/11.
 */
public interface EmployeeRepository extends Repository<Employee,Integer> {

//Repository<Employee,Integer> 操作的實體類和主鍵

/**
* 根據名字查詢員工
* @param name名字
* @return
*/
public Employee findByName(String name);


}

EmployeeRepositoryTest:

package com.hcx.repository;

import com.hcx.domain.Employee;
import org.junit.After;
import org.junit.Before;
import org.junit.Test;
import org.springframework.context.ApplicationContext;
import org.springframework.context.support.ClassPathXmlApplicationContext;

import static org.junit.Assert.*;

/**
 * Created by HCX on 2019/3/11.
 */
public class EmployeeRepositoryTest {

private ApplicationContext ctx = null;

private EmployeeRepository employeeRepository = null;

@Before
public void setup() {
ctx = new ClassPathXmlApplicationContext("beans-jpa.xml");
employeeRepository = ctx.getBean(EmployeeRepository.class);
System.out.println("setup");
}

@After
public void tearDown() {
ctx = null;
System.out.println("tearDown");
}

@Test
public void testFindByName() throws Exception {
Employee employee = employeeRepository.findByName("zhangsan");
System.out.println("id:" + employee.getId() + " " +
",name:" + employee.getName()
+ " age:" + employee.getAge());
}
}

二、Spring Data JPA介面

1.Repository介面：

Repository介面是Spring Data的核心介面，不提供任何方法

public interface Repository<T,ID extends Serializable>{}

T:要處理的實體類
ID：T中ID的型別
Repository是一個空介面，標記介面（沒有包含方法宣告的介面）

@RepositoryDefinition註解的使用

不繼承自Repository則可以使用@RepositoryDefinition：

@RepositoryDefinition(domainClass = Employee.class,idClass = Integer.class)
public interface EmployeeRepository {// extends Repository<Employee,Integer>

//Repository<Employee,Integer> 操作的實體類和主鍵

/**
* 根據名字查詢員工
* @param name名字
* @return
*/
public Employee findByName(String name);
}

2.Repository子介面：

①CrudRepository:繼承Repository，實現了CRUD相關的方法

②PagingAndSortingRepository:繼承CrudRepository，實現了分頁排序相關的方法。

③JpaRepository：繼承PagingAndSortingRepository，實現JPA規範相關的方法。

3.Repository中查詢方法定義規則和使用

1.SpringData中查詢方法名稱的定義規則

查詢規則定義和使用.png

EmployeeRepository:

package com.hcx.repository;

import com.hcx.domain.Employee;
import org.springframework.data.repository.Repository;
import org.springframework.data.repository.RepositoryDefinition;

import java.util.List;


/**
 * Created by HCX on 2019/3/11.
 */
@RepositoryDefinition(domainClass = Employee.class,idClass = Integer.class)
public interface EmployeeRepository {// extends Repository<Employee,Integer>

//Repository<Employee,Integer> 操作的實體類和主鍵

/**
* 根據名字查詢員工
* @param name名字
* @return
*/
public Employee findByName(String name);

/**
* 根據名字和年齡來查詢
* @param name 名字以某個字元開頭
* @param age 年齡小於多少
* @return
*/
public List<Employee> findByNameStartingWithAndAgeLessThan(String name,Integer age);


/**
* 根據名字和年齡來查詢
* @param name 名字以某個字元結束
* @param age
* @return 年齡小於多少
*/
public List<Employee> findByNameEndingWithAndAgeLessThan(String name,Integer age);

/**
* 根據名字和年齡來查詢
* @param names 名字在names集合中
* @param age
* @return
*/
public List<Employee> findByNameInOrAgeLessThan(List<String> names,Integer age);


/**
* 根據名字和年齡來查詢
* @param names
* @param age
* @return
*/
public List<Employee> findByNameInAndAgeLessThan(List<String> names,Integer age);



}

單元測試：

@Test
public void testFindByNameStartingWithAndAgeLessThan() throws Exception {
List<Employee> employees = employeeRepository.findByNameStartingWithAndAgeLessThan("test", 23);
for (Employee employee : employees) {
System.out.println("id:" + employee.getId() + " " +
",name:" + employee.getName()
+ " age:" + employee.getAge());
}

}

@Test
public void testFindByNameEndingWithAndAgeLessThan() throws Exception {
List<Employee> employees = employeeRepository.findByNameEndingWithAndAgeLessThan("6", 60);
for (Employee employee : employees) {
System.out.println("id:" + employee.getId() + " " +
",name:" + employee.getName()
+ " age:" + employee.getAge());
}

}

@Test
public void testFindByNameInOrAgeLessThan() throws Exception {
List<String> names = new ArrayList<String>();
names.add("test1");
names.add("test2");
names.add("test3");
List<Employee> employees = employeeRepository.findByNameInOrAgeLessThan(names, 22);
for (Employee employee : employees) {
System.out.println("id:" + employee.getId() + " " +
",name:" + employee.getName()
+ " age:" + employee.getAge());
}

}

@Test
public void testFindByNameInAndAgeLessThan() throws Exception {
List<String> names = new ArrayList<String>();
names.add("test1");
names.add("test2");
names.add("test3");
List<Employee> employees = employeeRepository.findByNameInAndAgeLessThan(names, 22);
for (Employee employee : employees) {
System.out.println("id:" + employee.getId() + " " +
",name:" + employee.getName()
+ " age:" + employee.getAge());
}

}

對於按照方法命名規則來使用的弊端：

方法名較長：約定大於配置
對於一些複雜的查詢，很難實現

2.使用SpringData完成複雜查詢方法名稱的命名

Query註解的使用：

在repository方法中使用，則不需要遵循查詢方法命名規則：

只需要將@Query定義在Repository中的方法之上即可
支援命名引數及索引引數的使用
支援本地查詢

EmployeeRepository：

/**
* 查詢員工表中id最大的資料
* @return
*/
@Query("select o from Employee o where id=(select max(id) from Employee t1)") //注意：此處Employee是類名
public Employee getEmployeeByMaxId();


/**
* 根據名字和年齡查詢 使用索引引數
* @param name
* @param age
* @return
*/
@Query("select o from Employee o where o.name=?1 and o.age=?2")
public List<Employee> queryParams1(String name,Integer age);


/**
* 根據名字和年齡查詢 使用命名引數
* @param name
* @param age
* @return
*/
@Query("select o from Employee o where o.name=:name and o.age=:age")
public List<Employee> queryParams2(@Param("name") String name, @Param("age") Integer age);


/**
* 模糊查詢 使用索引引數
* @param name
* @return
*/
@Query("select o from Employee o where o.name like %?1%")
public List<Employee> queryLike1(String name);


/**
* 模糊查詢 使用命名引數
* @param name
* @return
*/
@Query("select o from Employee o where o.name like %:name%")
public List<Employee> queryLike2(@Param("name")String name);


/**
* 使用原生態的方式查詢
* @return
*/
@Query(nativeQuery = true,value="select count(1) from employee") //原生態查詢，使用表名
public long getCount();
}

EmployeeRepositoryTest:

@Test
public void testGetEmployeeByMaxId() throws Exception {

Employee employee = employeeRepository.getEmployeeByMaxId();
System.out.println("id:" + employee.getId() + " " +
",name:" + employee.getName()
+ " age:" + employee.getAge());

}


@Test
public void testQueryParams1() throws Exception {

List<Employee> employees = employeeRepository.queryParams1("zhangsan", 20);
for (Employee employee:employees) {
System.out.println("id:" + employee.getId() + " " +
",name:" + employee.getName()
+ " age:" + employee.getAge());

}
}

@Test
public void testQueryParams2() throws Exception {
List<Employee> employees = employeeRepository.queryParams2("zhangsan", 20);
for (Employee employee:employees) {
System.out.println("id:" + employee.getId() + " " +
",name:" + employee.getName()
+ " age:" + employee.getAge());

}
}


@Test
public void testQueryLike1() throws Exception {
List<Employee> employees = employeeRepository.queryLike1("test");
for (Employee employee:employees) {
System.out.println("id:" + employee.getId() + " " +
",name:" + employee.getName()
+ " age:" + employee.getAge());

}
}

@Test
public void testQueryLike2() throws Exception {
List<Employee> employees = employeeRepository.queryLike2("test1");
for (Employee employee:employees) {
System.out.println("id:" + employee.getId() + " " +
",name:" + employee.getName()
+ " age:" + employee.getAge());

}
}

@Test
public void testGetCount() throws Exception {
long count = employeeRepository.getCount();
System.out.println("count:"+count);

}

更新及刪除操作：

@Modifying註解使用

@Modifying結合@Query註解執行更新操作

@Transaction在Spring Data中的使用

事務在service層中使用

EmployeeRepository：

/**
* 通過id更新年齡
* @param id
* @param age
*/
@Modifying
@Query("update Employee o set o.age=:age where o.id=:id")
public void update(@Param("id")Integer id,@Param("age")Integer age);

EmployeeService:

package com.hcx.service;

import com.hcx.repository.EmployeeRepository;
import org.springframework.beans.factory.annotation.Autowired;
import org.springframework.stereotype.Service;
import org.springframework.transaction.annotation.Transactional;

/**
 * Created by HCX on 2019/3/13.
 */
@Service
public class EmployeeService {

@Autowired
private EmployeeRepository employeeRepository;

@Transactional
public void update(Integer id,Integer age){
employeeRepository.update(id,age);
}


}

EmployeeServiceTest:

package com.hcx.service;

import com.hcx.domain.Employee;
import org.junit.After;
import org.junit.Before;
import org.junit.Test;
import org.springframework.beans.factory.annotation.Autowired;
import org.springframework.context.ApplicationContext;
import org.springframework.context.support.ClassPathXmlApplicationContext;

import static org.junit.Assert.*;

/**
 * Created by HCX on 2019/3/13.
 */
public class EmployeeServiceTest {

private ApplicationContext ctx = null;
private EmployeeService employeeService = null;


@Before
public void setup() {
ctx = new ClassPathXmlApplicationContext("beans-jpa.xml");
employeeService = ctx.getBean(EmployeeService.class);
System.out.println("setup");
}

@After
public void tearDown() {
ctx = null;
System.out.println("tearDown");
}


@Test
public void testUpdate() throws Exception {
employeeService.update(1, 55);
}
}

三、JPA中的常用介面

1.CrudRepository介面的使用

save(entity)
save(entities)
findOne(id)
exists(id)
findAll()
delete(id)
delete(entity)
delete(entities)
deleteAll()

EmployeeCrudRepository：

package com.hcx.repository;

import com.hcx.domain.Employee;
import org.springframework.data.repository.CrudRepository;

/**
 * Created by HCX on 2019/3/14.
 */
public interface EmployeeCrudRepository extends CrudRepository<Employee,Integer>{
}

EmployeeService:

@Transactional
public void save(List<Employee> employees){
employeeCrudRepository.save(employees);
}

testSave:

@Test
public void testSave() {

List<Employee> employees = new ArrayList<Employee>();

Employee employee = null;

for (int i = 0; i < 100; i++) {
employee = new Employee();
employee.setName("test" + 199);
employee.setAge(100);
//employee.setId(1);
employees.add(employee);
}

employeeService.save(employees);

}

2.PagingAndSortingRespository介面的使用

該介面包含分頁和排序的功能

帶排序的查詢：findAll(Sort sort)

帶排序的分頁查詢：findAll(Pageable pageable)

EmployeePagingAndSortingRepository：

package com.hcx.repository;

import com.hcx.domain.Employee;
import org.springframework.data.repository.PagingAndSortingRepository;

/**
 * Created by HCX on 2019/3/15.
 */
public interface EmployeePagingAndSortingRepository extends PagingAndSortingRepository<Employee,Integer>{
}

EmployeePagingAndSortingRepositoryTest:

package com.hcx.repository;

import com.hcx.domain.Employee;
import com.hcx.service.EmployeeService;
import org.junit.After;
import org.junit.Before;
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.Pageable;
import org.springframework.data.domain.Sort;

import java.util.ArrayList;
import java.util.List;

/**
 * Created by HCX on 2019/3/14.
 */
public class EmployeePagingAndSortingRepositoryTest {

private ApplicationContext ctx = null;
private EmployeePagingAndSortingRepository employeePagingAndSortingRepository = null;

@Before
public void setup() {
ctx = new ClassPathXmlApplicationContext("beans-jpa.xml");
employeePagingAndSortingRepository = ctx.getBean(EmployeePagingAndSortingRepository.class);
System.out.println("setup");
}

@After
public void tearDown() {
ctx = null;
System.out.println("tearDown");
}

@Test
public void testPage() {

/**
* PageRequest(int page, int size)
* page:從0開始
*/
Pageable pageable = new PageRequest(0,5);
Page<Employee> page = employeePagingAndSortingRepository.findAll(pageable);

System.out.println("查詢的總頁數："+page.getTotalPages());
System.out.println("查詢的總記錄數"+page.getTotalElements());
System.out.println("當前第幾頁"+page.getNumber());
System.out.println("當前頁面的集合"+page.getContent());
System.out.println("當前頁面的記錄數"+page.getNumberOfElements());

}

@Test
public void testPageAndSort(){
Sort.Order order = new Sort.Order(Sort.Direction.DESC,"id");
Sort sort = new Sort(order);

Pageable pageable = new PageRequest(0,5,sort);

Page<Employee> page = employeePagingAndSortingRepository.findAll(pageable);

System.out.println("查詢的總頁數："+page.getTotalPages());
System.out.println("查詢的總記錄數"+page.getTotalElements());
System.out.println("當前第幾頁"+page.getNumber());
System.out.println("當前頁面的集合"+page.getContent());
System.out.println("當前頁面的記錄數"+page.getNumberOfElements());

}

}

3.JpaRespository介面的使用

findAll
findAll(Sort sort)
save(entities)
flush
deleteInBatch(entities)

EmployeeJpaRepository:

package com.hcx.repository;

import com.hcx.domain.Employee;
import org.springframework.data.jpa.repository.JpaRepository;
import org.springframework.data.repository.PagingAndSortingRepository;

/**
 * Created by HCX on 2019/3/15.
 */
public interface EmployeeJpaRepository extends JpaRepository<Employee,Integer>{
}

EmployeeJpaRepositoryTest:

package com.hcx.repository;

import com.hcx.domain.Employee;
import org.junit.After;
import org.junit.Before;
import org.junit.Test;
import org.springframework.context.ApplicationContext;
import org.springframework.context.support.ClassPathXmlApplicationContext;

import static org.junit.Assert.*;

/**
 * Created by HCX on 2019/3/15.
 */
public class EmployeeJpaRepositoryTest {

private ApplicationContext ctx = null;
private EmployeeJpaRepository employeeJpaRepository = null;

@Before
public void setup() {
ctx = new ClassPathXmlApplicationContext("beans-jpa.xml");
employeeJpaRepository = ctx.getBean(EmployeeJpaRepository.class);
System.out.println("setup");
}

@After
public void tearDown() {
ctx = null;
System.out.println("tearDown");
}

@Test
public void testFind(){
Employee employee = employeeJpaRepository.findOne(99);
System.out.println("employee:"+employee);
System.out.println("employee(10):"+employeeJpaRepository.exists(10));
System.out.println("employee(1000):"+employeeJpaRepository.exists(1000));
}

}

4.JpaSpecificationExecutor介面的使用

Specification封裝了JPA Criteria查詢條件

EmployeeJpaSpecificationExecutorRepository：

package com.hcx.repository;

import com.hcx.domain.Employee;
import org.springframework.data.jpa.repository.JpaRepository;
import org.springframework.data.jpa.repository.JpaSpecificationExecutor;

/**
 * Created by HCX on 2019/3/15.
 */
public interface EmployeeJpaSpecificationExecutorRepository
extends JpaRepository<Employee,Integer>,JpaSpecificationExecutor<Employee>{
}

EmployeeJpaSpecificationExecutorRepositoryTest:

package com.hcx.repository;

import com.hcx.domain.Employee;
import com.hcx.service.EmployeeService;
import org.junit.After;
import org.junit.Before;
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.Pageable;
import org.springframework.data.domain.Sort;
import org.springframework.data.jpa.domain.Specification;

import javax.persistence.criteria.*;

import static org.junit.Assert.*;

/**
 * Created by HCX on 2019/3/15.
 */
public class EmployeeJpaSpecificationExecutorRepositoryTest {

private ApplicationContext ctx = null;
private EmployeeJpaSpecificationExecutorRepository employeeJpaSpecificationExecutorRepository = null;

@Before
public void setup() {
ctx = new ClassPathXmlApplicationContext("beans-jpa.xml");
employeeJpaSpecificationExecutorRepository = ctx.getBean(EmployeeJpaSpecificationExecutorRepository.class);
System.out.println("setup");
}

@After
public void tearDown() {
ctx = null;
System.out.println("tearDown");
}

@Test
public void testQuery() {
Sort.Order order = new Sort.Order(Sort.Direction.DESC, "id");
Sort sort = new Sort(order);

Pageable pageable = new PageRequest(0, 5, sort);

Specification<Employee> specification = new Specification<Employee>() {

/**
*
* @param root 要查詢的條件（Employee）
* @param criteriaQuery新增查詢條件
* @param criteriaBuilder 構建Predicate
* @return
*/
@Override
public Predicate toPredicate(Root<Employee> root,
CriteriaQuery<?> criteriaQuery,
CriteriaBuilder criteriaBuilder) {
//root(employee(age))
Path path = root.get("age");
Predicate predicate = criteriaBuilder.gt(path, 50);
return predicate;
}
};

Page<Employee> page = employeeJpaSpecificationExecutorRepository.findAll(specification,pageable);

System.out.println("查詢的總頁數：" + page.getTotalPages());
System.out.println("查詢的總記錄數" + page.getTotalElements());
System.out.println("當前第幾頁" + page.getNumber());
System.out.println("當前頁面的集合" + page.getContent());
System.out.println("當前頁面的記錄數" + page.getNumberOfElements());
}


}

補充：

更新操作時，先查詢出來，再設定某個屬性，此時updateTime不會自動更新，這是需要在實體上加上@DynamicUpdate註解

使用lombok外掛簡化實體的書寫：

xml：

<dependency>
<groupId>org.projectlombok</groupId>
<artifactId>lombok</artifactId>
</dependency>

在IDEA中使用需要安裝相應的外掛

通過在實體上加上@Data註解，簡化get()、set()、toString()等方法的書寫

如果只想省略get方法，可以使用@Getter註解

@Entity
@DynamicUpdate
@Data
public class ProductCategory {

/** 類目id. */
@Id //主鍵
@GeneratedValue //自增
private Integer categoryId;

/** 類目名字. */
private String categoryName;

/** 類目編號. */
private Integer categoryType;

private Date createTime;
private Date updateTime;

}

Demo連結： https://github.com/GitHongcx/springdataDemo

注：本文部分內容來自慕課網

Spring Data下---Spring Data JPA的使用