SpringBoot整合SpringDataJPA

一、SpringBootData JPA介绍
  SpringData：其实SpringData就是Spring提供了一个操作数据的框架。而SpringData JPA只是SpringData框架下的一个基于JPA标准操作数据的模块。
  SpringData JPA：基于JPA的标准数据进行操作。简化操作持久层的代码。只需要编写接口就可以。
 
 
二、SpringBoot整合SpringData JPA
 
1、导入maven依赖
 在原有的SprigBoot的maven依赖的基础下加上JPA的依赖

 
2、application.properties文件中添加配置

 
3、实体类

import javax.persistence.*;

@Entity
@Table(name="t_users")
public class Users {

@Id	//主键id
@GeneratedValue(strategy=GenerationType.IDENTITY)//主键生成策略
@Column(name="id")//数据库字段名
private Integer id;

@Column(name="name")
private String name;

@Column(name="age")
private Integer age;

@Column(name="address")
private String address;

@ManyToOne(cascade = CascadeType.PERSIST)	//表示多方
@JoinColumn(name ="role_id")	//维护一个外键，外键在Users一侧
private Roles roles;

public Roles getRoles() {
return roles;
}

public void setRoles(Roles roles) {
this.roles = roles;
}

public Integer getId() {
return id;
}

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

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;
}

public String getAddress() {
return address;
}

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

@Override
public String toString() {
final StringBuffer sb = new StringBuffer("Users{");
sb.append("id=").append(id);
sb.append(", name='").append(name).append('\'');
sb.append(", age=").append(age);
sb.append(", address='").append(address).append('\'');
sb.append(", roles=").append(roles);
sb.append('}');
return sb.toString();
}
}

 
4、编写Dao接口

import org.springframework.data.jpa.repository.JpaRepository;

import com.bjsxt.pojo.Users;
/**
* 参数一 T :当前需要映射的实体
* 参数二 ID :当前映射的实体中的OID的类型
*
*/
public interface UsersRepository extends JpaRepository<Users,Integer> {

}

 
6、在pom文件中添加测试启动器的坐标

 
7、测试

 
 
三、SpringBoot JPA提供的核心接口
 
 1、Repository接口
 2、CrudRepository接口
 3、PagingAndSortingRepository接口
 4、JpaRepository接口
 5、JPASpecificationExecutor接口
 
 
四、Repository接口的使用
 
 提供了方法名称命名查询方式
 提供了基于@Query注解查询与更新
 
1、dao层接口（方法名称命名查询方式）

import com.bjsxt.pojo.Users;
import org.springframework.data.repository.Repository;

import java.util.List;

/**
* Repository接口方法名称命名查询
*
*/
public interface UsersRepositoryByName extends Repository<Users,Integer> {
//方法名称必须要遵循驼峰式命名规则，findBy（关键字）+属性名称（首字母大写）+查询条件（首字母大写）
List<Users> findByName(String name);

List<Users> findByNameAndAge(String name,Integer age);

List<Users> findByNameLike(String name);

}

 
2、测试

/**
* Repository
*/
@Test
public void UsersRepositoryByName(){
List<Users> list=this.usersRepositoryByName.findByName("张三");
for (Users users:list){
System.out.println(users);
}
}

@Test
public void findByNameAndAge(){
List<Users> list=this.usersRepositoryByName.findByNameAndAge("张三",20);
for (Users users:list){
System.out.println(users);
}
}

@Test
public void findByNameLike() {
List<Users> list = this.usersRepositoryByName.findByNameLike("张%");
for (Users users : list) {
System.out.println(users);
}
}

 
3、dao层接口编写（基于@Query注解查询与更新）

import com.bjsxt.pojo.Users;
import org.springframework.data.jpa.repository.JpaRepository;
import org.springframework.data.jpa.repository.Modifying;
import org.springframework.data.jpa.repository.Query;

import java.util.List;

/**
* 〈一句话功能简述〉<br>
*  Repository    @Query
*
* @author admin
* @create 2019/5/22
* @since 1.0.0
*/
public interface UsersRepositoryQueryAnnotation extends JpaRepository<Users,Integer> {
@Query("from Users where name = ?")
List<Users> queryByNameUseHQL(String name);

@Query(value = "select * from t_user where name=?",nativeQuery = true)
List<Users> queryByNameUseSQL(String name);

@Query("update Users set name=? where id=?")
@Modifying  //需要执行一个更新操作
void updateUsersNameById(String name,Integer id);

}

 
4、测试

/**
* Repository--@Query测试
*/
@Test
public void testQueryByNameUseSQL() {
List<Users> list = this.usersRepositoryQueryAnnotation.queryByNameUseSQL("张三");
for (Users users : list) {
System.out.println(users);
}
}

/**
* Repository--@Query测试
*/
@Test
@Transactional //@Transactional与@Test 一起使用时 事务是自动回滚的。
@Rollback(false) //取消自动回滚
public void testUpdateUsersNameById() {
this.usersRepositoryQueryAnnotation.updateUsersNameById("张三三", 1);
}

 
 
五、CrudRepository接口的使用
  CrudRepository接口,主要是完成一些增删改查的操作。注意：CrudRepository接口继承了Repository接口
 
1、编写dao层接口

import com.bjsxt.pojo.Users;
import org.springframework.data.repository.CrudRepository;

public interface UsersRepositoryCrudRepository extends CrudRepository<Users,Integer> {
}

 
2、测试

@Test
public void testCrudRepositorySave() {
Users users=new Users();
users.setName("青衫");
users.setAge(30);
users.setAddress("湖南怀化");
this.usersRepositoryCrudRepository.save(users);
}

@Test
public void testCrudRepositoryUpdate() {
Users users=new Users();
users.setId(4);
users.setName("青");
users.setAge(18);
users.setAddress("怀化");
this.usersRepositoryCrudRepository.save(users);
}

@Test
public void testCrudRepositoryFindOne() {

Users users=this.usersRepositoryCrudRepository.findOne(4);
System.out.println(users);
}

@Test
public void testCrudRepositoryFindAll() {
List<Users> list= (List<Users>) this.usersRepositoryCrudRepository.findAll();
for (Users user:list){
System.out.println(user);
}
}

@Test
public void testCrudRepositoryDeleteById() {
this.usersRepositoryCrudRepository.delete(4);

}

 
 
六、PagingAndSortingRepository接口的使用
 该接口提供了分页与排序的操作，注意：该接口继承了CrudRepository接口
 
1、编写dao层

import com.bjsxt.pojo.Users;
import org.springframework.data.repository.PagingAndSortingRepository;

public interface UsersRepositoryPagingAndSorting extends PagingAndSortingRepository<Users,Integer> {

}

 
2、测试

@Test
public void testPagingAndSortingRepositorySort() {
//Order	定义了排序规则
Sort.Order order=new Sort.Order(Sort.Direction.DESC,"id");
//Sort对象封装了排序规则
Sort sort=new Sort(order);
List<Users> list= (List<Users>) this.usersRepositoryPagingAndSorting.findAll(sort);
for (Users users:list){
System.out.println(users);
}
}

@Test
public void testPagingAndSortingRepositoryPaging() {
//Pageable:封装了分页的参数，当前页，煤业显示的条数。注意：它的当前页是从0开始
//PageRequest(page,size):page表示当前页，size表示每页显示多少条
Pageable pageable=new PageRequest(1,2);
Page<Users> page=this.usersRepositoryPagingAndSorting.findAll(pageable);
System.out.println("数据的总条数："+page.getTotalElements());
System.out.println("总页数："+page.getTotalPages());
List<Users> list=page.getContent();
for (Users users:list){
System.out.println(users);
}
}

@Test
public void testPagingAndSortingRepositorySortAndPaging() {
Sort sort=new Sort(new S
7ff7
ort.Order(Sort.Direction.DESC,"id"));
Pageable pageable=new PageRequest(0,2,sort);
Page<Users> page=this.usersRepositoryPagingAndSorting.findAll(pageable);
System.out.println("数据的总条数："+page.getTotalElements());
System.out.println("总页数："+page.getTotalPages());
List<Users> list=page.getContent();
for (Users users:list){
System.out.println(users);
}
}

 
 
七、JpaRepository接口
 
 该接口继承了PagingAndSortingRepository。对继承的父接口中方法的返回值进行适配。
 
1、dao层接口编写

/**
* 参数一 T :当前需要映射的实体
* 参数二 ID :当前映射的实体中的OID的类型
*
*/
public interface UsersRepository extends JpaRepository<Users,Integer> {

}

 
2、测试

/**
* JpaRepository	排序测试
*/
@Test
public void testJpaRepositorySort() {
//Order	定义了排序规则
Sort.Order order=new Sort.Order(Sort.Direction.DESC,"id");
//Sort对象封装了排序规则
Sort sort=new Sort(order);
List<Users> list= this.usersRepository.findAll(sort);
for (Users users:list){
System.out.println(users);
}
}

 
 
八、JPASpecificationExecutor接口
 
 该接口主要是提供了多条件查询的支持，并且可以在查询中添加排序与分页。注意JPASpecificationExecutor是单独存在的。完全独立
 
1、dao层接口编写

import com.bjsxt.pojo.Users;
import org.springframework.data.jpa.repository.JpaRepository;
import org.springframework.data.jpa.repository.JpaSpecificationExecutor;

/**
* 〈一句话功能简述〉<br>
*  JpaSpecificationExecutor
*
* @author admin
* @create 2019/5/23
* @since 1.0.0
*/
public interface UserRepositorySpecification extends JpaRepository<Users,Integer>,JpaSpecificationExecutor<Users> {
}

 
2、测试

/**
* JpaSpecificationExecutor		单条件查询
*/
@Test
public void testJpaSpecificationExecutor1() {
/**
* Specification:用于封装查查询条件
*/
Specification<Users> spec=new Specification<Users>() {
//Predicate：封装了单个查询条件

/**
* @param root		对查询对象属性的封装
* @param criteriaQuery	封装了我们要执行的查询中的各个部分的信息，select from order
* @param criteriaBuilder	查询条件的构造器
* @return
*/
@Override
public Predicate toPredicate(Root<Users> root, CriteriaQuery<?> criteriaQuery, CriteriaBuilder criteriaBuilder) {
//where name="张三"
/**
* 参数一：查询的属性
* 参数二：条件的值
*/
Predicate predicate=criteriaBuilder.equal(root.get("name"),"张三");
return predicate;
}
};
List<Users> list=this.userRepositorySpecification.findAll(spec);
for (Users users:list){
System.out.println(users);
}
}

/**
* JpaSpecificationExecutor		多条件查询方式一
*/
@Test
public void testJpaSpecificationExecutor2() {
/**
* Specification:用于封装查查询条件
*/
Specification<Users> spec=new Specification<Users>() {
//Predicate：封装了单个查询条件

/**
* @param root		对查询对象属性的封装
* @param criteriaQuery	封装了我们要执行的查询中的各个部分的信息，select from order
* @param criteriaBuilder	查询条件的构造器
* @return
*/
@Override
public Predicate toPredicate(Root<Users> root, CriteriaQuery<?> criteriaQuery, CriteriaBuilder criteriaBuilder) {
//where name="张三" and age=20
/**
* 参数一：查询的属性
* 参数二：条件的值
*/
List<Predicate> list=new ArrayList<>();
list.add(criteriaBuilder.equal(root.get("name"),"张三"));
list.add(criteriaBuilder.equal(root.get("age"),20));
Predicate[] arr=new Predicate[list.size()];
return criteriaBuilder.and(list.toArray(arr));
}
};
List<Users> list=this.userRepositorySpecification.findAll(spec);
for (Users users:list){
System.out.println(users);
}
}

/**
* JpaSpecificationExecutor		多条件查询方式二
*/
@Test
public void testJpaSpecificationExecutor3() {
/**
* Specification:用于封装查查询条件
*/
Specification<Users> spec=new Specification<Users>() {
//Predicate：封装了单个查询条件

/**
* @param root		对查询对象属性的封装
* @param criteriaQuery	封装了我们要执行的查询中的各个部分的信息，select from order
* @param criteriaBuilder	查询条件的构造器
* @return
*/
@Override
public Predicate toPredicate(Root<Users> root, CriteriaQuery<?> criteriaQuery, CriteriaBuilder criteriaBuilder) {
//where name="张三" and age=20
/**
* 参数一：查询的属性
* 参数二：条件的值
*/
/*List<Predicate> list=new ArrayList<>();
list.add(criteriaBuilder.equal(root.get("name"),"张三"));
list.add(criteriaBuilder.equal(root.get("age"),20));
Predicate[] arr=new Predicate[list.size()];*/
//(name='张三' and age=20) or id=2
return criteriaBuilder.or(criteriaBuilder.and(criteriaBuilder.equal(root.get("name"),"张三"),criteriaBuilder.equal(root.get("age"),20)),criteriaBuilder.equal(root.get("id"),1));
}
};

Sort sort=new Sort(new Sort.Order(Sort.Direction.DESC,"id"));
List<Users> list=this.userRepositorySpecification.findAll(spec,sort);
for (Users users:list){
System.out.println(users);
}
}

 
 
九、关联映射操作
 
1、一对多的关联关系
  需求：角色与用户的一对多的关联关系
  角色：一方
  用户：多方
 
2、实体类

import javax.persistence.*;
import java.util.HashSet;
import java.util.Set;

/**
* 〈一句话功能简述〉<br>
* 〈〉
*
* @author admin
* @create 2019/5/23
* @since 1.0.0
*/
@Entity
@Table(name = "t_roles")
public class Roles {
@Id
@GeneratedValue(strategy = GenerationType.IDENTITY)
@Column(name = "role_id")
private Integer roleId;
@Column(name = "role_name")
private String roleName;

@OneToMany(mappedBy = "roles")
private Set<Users> users=new HashSet<>();

public Integer getRoleId() {
return roleId;
}

public void setRoleId(Integer roleId) {
this.roleId = roleId;
}

public String getRoleName() {
return roleName;
}

public void setRoleName(String roleName) {
this.roleName = roleName;
}

public Set<Users> getUsers() {
return users;
}

public void setUsers(Set<Users> users) {
this.users = users;
}

}

package com.bjsxt.pojo;

import javax.persistence.*;

@Entity
@Table(name="t_users")
public class Users {

@Id	//主键id
@GeneratedValue(strategy=GenerationType.IDENTITY)//主键生成策略
@Column(name="id")
private Integer id;

@Column(name="name")
private String name;

@Column(name="age")
private Integer age;

@Column(name="address")
private String address;

@ManyToOne(cascade = CascadeType.PERSIST)	//表示多方
@JoinColumn(name ="role_id")	//维护一个外键，外键在Users一侧
private Roles roles;

public Roles getRoles() {
return roles;
}

public void setRoles(Roles roles) {
this.roles = roles;
}

public Integer getId() {
return id;
}

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

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;
}

public String getAddress() {
return address;
}

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

@Override
public String toString() {
final StringBuffer sb = new StringBuffer("Users{");
sb.append("id=").append(id);
sb.append(", name='").append(name).append('\'');
sb.append(", age=").append(age);
sb.append(", address='").append(address).append('\'');
sb.append(", roles=").append(roles);
sb.append('}');
return sb.toString();
}
}

 
3、dao层接口编写

/**
* 参数一 T :当前需要映射的实体
* 参数二 ID :当前映射的实体中的OID的类型
*
*/
public interface UsersRepository extends JpaRepository<Users,Integer> {

}

 
4、测试

/**
* Copyright (C), 2015-2019, XXX有限公司
* FileName: ManyToManyTest
* Author:   admin
* Date:     2019/5/23 14:19
* Description:
* History:
* <author>          <time>          <version>          <desc>
* 作者姓名           修改时间           版本号              描述
*/
package com.bjsxt.test;

import com.bjsxt.App;
import com.bjsxt.dao.RolesRepository;
import com.bjsxt.pojo.Menus;
import com.bjsxt.pojo.Roles;
import org.junit.Test;
import org.junit.runner.RunWith;
import org.springframework.beans.factory.annotation.Autowired;
import org.springframework.boot.test.context.SpringBootTest;
import org.springframework.test.context.junit4.SpringJUnit4ClassRunner;

import java.util.Set;

/**
* 〈一句话功能简述〉<br>
* 多对多的关联关系的测试
*
* @author admin
* @create 2019/5/23
* @since 1.0.0
*/
@RunWith(SpringJUnit4ClassRunner.class)
@SpringBootTest(classes = App.class)
public class ManyToManyTest {

@Autowired
private RolesRepository rolesRepository;

/**
* 添加测试
*/
@Test
public void testSave(){
//创建角色对象
Roles roles=new Roles();
roles.setRoleName("项目经理");
//创建菜单对象
Menus menus=new Menus();
menus.setMenusName("xxxx管理系统");
menus.setFatherId(0);

Menus menus2=new Menus();
menus2.setFatherId(1);
menus2.setMenusName("项目管理");
//关联
roles.getMenus().add(menus);
roles.getMenus().add(menus2);
menus.getRoles().add(roles);
menus2.getRoles().add(roles);
//保存
this.rolesRepository.save(roles);
}

/**
* 查询操作
*/
@Test
public void testFind(){
Roles roles=this.rolesRepository.findOne(2);
System.out.println(roles.getRoleName());
Set<Menus> menus=roles.getMenus();
for (Menus menu:menus){
System.out.println(menu);
}
}
}

&nbsp；
5、多对多的关联关系
&nbsp；
 角色与菜单多对多关联关系
 菜单：多方
 角色：多方
 
6、实体类

/**
* Copyright (C), 2015-2019, XXX有限公司
* FileName: Menus
* Author:   admin
* Date:     2019/5/23 14:06
* Description:
* History:
* <author>          <time>          <version>          <desc>
* 作者姓名           修改时间           版本号              描述
*/
package com.bjsxt.pojo;

import javax.persistence.*;
import java.util.HashSet;
import java.util.Set;

/**
* 〈一句话功能简述〉<br>
* 〈〉
*
* @author admin
* @create 2019/5/23
* @since 1.0.0
*/
@Entity
@Table(name = "t_menus")
public class Menus {
@Id
@GeneratedValue(strategy = GenerationType.IDENTITY)
@Column(name = "menus_id")
private Integer menusId;
@Column(name = "menus_name")
private String menusName;
@Column(name = "menus_url")
private String menusUrl;
@Column(name = "father_id")
private Integer fatherId;

@ManyToMany(mappedBy = "menus")
private Set<Roles> roles=new HashSet<>();

public Set<Roles> getRoles() {
return roles;
}

public void setRoles(Set<Roles> roles) {
this.roles = roles;
}

public Integer getMenusId() {
return menusId;
}

public void setMenusId(Integer menusId) {
this.menusId = menusId;
}

public String getMenusName() {
return menusName;
}

public void setMenusName(String menusName) {
this.menusName = menusName;
}

public String getMenusUrl() {
return menusUrl;
}

public void setMenusUrl(String menusUrl) {
this.menusUrl = menusUrl;
}

public Integer getFatherId() {
return fatherId;
}

public void setFatherId(Integer fatherId) {
this.fatherId = fatherId;
}

@Override
public String toString() {
final StringBuffer sb = new StringBuffer("Menus{");
sb.append("menusId=").append(menusId);
sb.append(", menusName='").append(menusName).append('\'');
sb.append(", menusUrl='").append(menusUrl).append('\'');
sb.append(", fatherId=").append(fatherId);
sb.append('}');
return sb.toString();
}
}

/**
* Copyright (C), 2015-2019, XXX有限公司
* FileName: Roles
* Author:   admin
* Date:     2019/5/23 11:02
* Description:
* History:
* <author>          <time>          <version>          <desc>
* 作者姓名           修改时间           版本号              描述
*/
package com.bjsxt.pojo;

import javax.persistence.*;
import java.util.HashSet;
import java.util.Set;

/**
* 〈一句话功能简述〉<br>
* 〈〉
*
* @author admin
* @create 2019/5/23
* @since 1.0.0
*/
@Entity
@Table(name = "t_roles")
public class Roles {
@Id
@GeneratedValue(strategy = GenerationType.IDENTITY)
@Column(name = "role_id")
private Integer roleId;
@Column(name = "role_name")
private String roleName;

@OneToMany(mappedBy = "roles")
private Set<Users> users=new HashSet<>();

@ManyToMany(cascade = CascadeType.PERSIST,fetch = FetchType.EAGER)
//映射中间表  joinColumns:当前表中的主键关联中间表的外键
@JoinTable(name = "t_roles_menus",joinColumns =@JoinColumn(name = "role_id"),inverseJoinColumns = @JoinColumn(name = "menu_id"))
private Set<Menus> menus=new HashSet<>();

public Set<Menus> getMenus() {
return menus;
}

public void setMenus(Set<Menus> menus) {
this.menus = menus;
}

public Integer getRoleId() {
return roleId;
}

public void setRoleId(Integer roleId) {
this.roleId = roleId;
}

public String getRoleName() {
return roleName;
}

public void setRoleName(String roleName) {
this.roleName = roleName;
}

public Set<Users> getUsers() {
return users;
}

public void setUsers(Set<Users> users) {
this.users = users;
}
}

 
7、dao层接口

/**
* Copyright (C), 2015-2019, XXX有限公司
* FileName: RolesRepository
* Author:   admin
* Date:     2019/5/23 14:21
* Description:
* History:
* <author>          <time>          <version>          <desc>
* 作者姓名           修改时间           版本号              描述
*/
package com.bjsxt.dao;

import com.bjsxt.pojo.Roles;
import org.springframework.data.jpa.repository.JpaRepository;

/**
* 〈一句话功能简述〉<br>
* 〈〉
*
* @author admin
* @create 2019/5/23
* @since 1.0.0
*/
public interface RolesRepository extends JpaRepository<Roles,Integer> {

}

 
8、测试

/**
* Copyright (C), 2015-2019, XXX有限公司
* FileName: ManyToManyTest
* Author:   admin
* Date:     2019/5/23 14:19
* Description:
* History:
* <author>          <time>          <version>          <desc>
* 作者姓名           修改时间           版本号              描述
*/
package com.bjsxt.test;

import com.bjsxt.App;
import com.bjsxt.dao.RolesRepository;
import com.bjsxt.pojo.Menus;
import com.bjsxt.pojo.Roles;
import org.junit.Test;
import org.junit.runner.RunWith;
import org.springframework.beans.factory.annotation.Autowired;
import org.springframework.boot.test.context.SpringBootTest;
import org.springframework.test.context.junit4.SpringJUnit4ClassRunner;

import java.util.Set;

/**
* 〈一句话功能简述〉<br>
* 多对多的关联关系的测试
*
* @author admin
* @create 2019/5/23
* @since 1.0.0
*/
@RunWith(SpringJUnit4ClassRunner.class)
@SpringBootTest(classes = App.class)
public class ManyToManyTest {

@Autowired
private RolesRepository rolesRepository;

/**
* 添加测试
*/
@Test
public void testSave(){
//创建角色对象
Roles roles=new Roles();
roles.setRoleName("项目经理");
//创建菜单对象
Menus menus=new Menus();
menus.setMenusName("xxxx管理系统");
menus.setFatherId(0);

Menus menus2=new Menus();
menus2.setFatherId(1);
menus2.setMenusName("项目管理");
//关联
roles.getMenus().add(menus);
roles.getMenus().add(menus2);
menus.getRoles().add(roles);
menus2.getRoles().add(roles);
//保存
this.rolesRepository.save(roles);
}

/**
* 查询操作
*/
@Test
public void testFind(){
Roles roles=this.rolesRepository.findOne(2);
System.out.println(roles.getRoleName());
Set<Menus> menus=roles.getMenus();
for (Menus menu:menus){
System.out.println(menu);
}
}
}