Java框架_SpringBoot整合Spring Data JPA
一、Spring Data JPA介绍
spring data：其实就是spring 提供的一个操作数据的框架。而spring data JPA 只是spring data 框架下的一个基于JPA标准操作数据的模块。
spring data jpa ：基于JPA的标准对数据进行操作。简化操作持久层的代码，只需要编写接口就可以。
二、spring boot 整合spring data jpa
1、搭建整合环境
2、修改pom.xml文件添加所需依赖
4.0.0
com.lxp
framework
0.0.1-SNAPSHOT
org.springframework.boot
spring-boot-starter-parent
1.5.10.RELEASE
1.7
org.springframework.boot
spring-boot-starter-web
org.springframework.boot
spring-boot-starter-test
mysql
mysql-connector-java
com.alibaba
druid
1.0.9
org.springframework.boot
spring-boot-starter-data-jpa
3、在项目中添加application.properties文件，添加数据库配置以及JPA配置
# 数据库配置
spring.datasource.type = com.alibaba.druid.pool.DruidDataSource
spring.datasource.driverClassName = com.mysql.jdbc.Driver
spring.datasource.url = jdbc:mysql://localhost:3306/framework
spring.datasource.username = root
spring.datasource.password = root
# SpringData JPA 配置
spring.jpa.hibernate.ddl-auto = update
spring.jpa.show-sql = true4、添加实体类
@Entity
@Table(name = "sys_users")
public class SysUsers {
@Id
@GeneratedValue(strategy = GenerationType.IDENTITY)
@Column(name = "id")
private Integer id;
@Column(name = "name")
private String name;
@Column(name = "age")
private Integer age;
@Column(name = "addr")
private String addr;
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 getAddr() {
return addr;
}
public void setAddr(String addr) {
this.addr = addr;
}5、添加接口
public interface SysUsersRepository extends JpaRepository {
/**
* JpaRepository
*
* T:当前需要映射的实体。 ID:当前映射实体中ID的类型
*/
}
6、创建启动类
@SpringBootApplication
public class AppStart {
public static void main(String[] args) {
SpringApplication.run(AppStart.class, args);
}
}7、编写测试代码
@RunWith(SpringJUnit4ClassRunner.class)
@SpringBootTest(classes = AppStart.class)
public class RepositoryTest {
@Autowired
private SysUsersRepository sysUsersRepository;
@Test
public void save() {
SysUsers users = new SysUsers();
users.setAddr("USA");
users.setAge(12);
users.setName("lucy");
this.sysUsersRepository.save(users);
}
}启动测试方法，如果数据库有插入这个人，那么这个接口就是可行的。
三、Spring Data JPA提供的核心接口
- Repository 接口
- CrudRepository 接口
- pagingAndSortingRepository 接口
- JpaRepository 接口
- JpaSpecificationExecutor 接口
四、Repository接口的使用
该接口给我们提供了两种查询方法：方法名称命名查询方式，基于@Query注解的查询与更新。
1、方法名称命名查询方式
- 编写接口
public interface SysUsersRepository extends Repository {
/**
* 方法名称名称查询方式
*
* 名称规则：方法的名称必须遵循驼峰式名称规则 : findBy(关键字) + 属性名称（首字母大写） + 查询条件（首字母大写）
*/
// 单条件
List findByName(String name);
// 多条件（and）
List findByNameAndAge(String name, int age);
// 多条件（or）
List findByNameOrAge(String name, int age);
// 单条件（like）
List findByNameLike(String name);
} - 编写测试代码
package com.lxp.test.repository;
import java.util.List;
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 com.lxp.AppStart;
import com.lxp.dao.SysUsersRepository;
import com.lxp.pojo.SysUsers;
/**
* @author lxp
* @date 2018年7月12日 上午9:32:31
* @parameter
* @return
*/
@RunWith(SpringJUnit4ClassRunner.class)
@SpringBootTest(classes = AppStart.class)
public class RepositoryTest {
@Autowired
private SysUsersRepository sysUsersRepository;
/**
* 单条件查询测试
*/
@Test
public void TestfindByName() {
List ls = this.sysUsersRepository.findByName("Lucy");
for (SysUsers sysUsers : ls) {
System.out.println(sysUsers);
}
List ls2 = this.sysUsersRepository.findByNameLike("%Lucy%");
for (SysUsers sysUsers : ls2) {
System.out.println(sysUsers);
}
}
/**
* 多条件查询测试
*/
@Test
public void TestfindByNameAndAge() {
List ls = this.sysUsersRepository.findByNameAndAge("Lucy", 12);
for (SysUsers sysUsers : ls) {
System.out.println(sysUsers);
}
List ls2 = this.sysUsersRepository.findByNameOrAge("Lucy", 12);
for (SysUsers sysUsers : ls2) {
System.out.println(sysUsers);
}
}
}
2、基于@Query注解的查询与更新
- 编写接口
public interface SysUsersRepositoryQueryAnnotation extends Repository {
// 注意点：这种写法语句中 SysUsers 必须是和实体类名称一样 不能是数据里的表名称（sys_users）
// 底层会对HQL语句就行转换,这种方法nativeQuery默认为false
@Query("from SysUsers where name = ?")
List QueryByNameHQL(String name);
// 注意点：nativeQuery= true 说明这的语句就是正常的SQL语句，底层不会对改语句进行转换
@Query(value = "select * from sys_users where name = ?", nativeQuery = true)
List QueryByNameSQL(String name);
@Query("update SysUsers set name = ? where id =?")
@Modifying // 需要加上@Modifying Annotation
void UpdateSysUsersNameById(String name, Integer id);
} - 编写测试类
@RunWith(SpringJUnit4ClassRunner.class)
@SpringBootTest(classes = AppStart.class)
public class RepositoryTest {
@Autowired
private SysUsersRepositoryQueryAnnotation sysUsersRepositoryQueryAnnotation;
@Test
public void TestQueryByNameHQL() {
List ls = this.sysUsersRepositoryQueryAnnotation.QueryByNameHQL("Lucy");
for (SysUsers sysUsers : ls) {
System.out.println(sysUsers);
}
List ls2 = this.sysUsersRepositoryQueryAnnotation.QueryByNameSQL("Lucy");
for (SysUsers sysUsers : ls2) {
System.out.println(sysUsers);
}
}
@Test
@Transactional // 注意: @Transactional和@Test一起用的时候事务是自动回滚的
// 所以需要加上@Rollback(false) 标识不回滚
@Rollback(false)
public void TestUpdateSysUsersNameById() {
this.sysUsersRepositoryQueryAnnotation.UpdateSysUsersNameById("LucyLily", 2);
}
} 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接口集成了Repository接口。
- 编写接口
public interface SysUsersCrudRepository extends CrudRepository {
/**
* 先不需要写接口
*/
} - 编写测试类
@RunWith(SpringJUnit4ClassRunner.class)
@SpringBootTest(classes = AppStart.class)
public class RepositoryTest {
@Autowired
private SysUsersCrudRepository sysUsersCrudRepository;
@Test
public void TestSysUsersCrudRepositorySave() {
SysUsers users = new SysUsers();
users.setAddr("北京");
users.setAge(25);
users.setName("李四");
this.sysUsersCrudRepository.save(users);
}
@Test
public void TestSysUsersCrudRepositoryUpdate() {
SysUsers users = new SysUsers();
users.setId(5);
users.setAddr("北京海淀区");
users.setAge(25);
users.setName("李四");
this.sysUsersCrudRepository.save(users);
}
@Test
public void TestSysUsersCrudRepositoryFindOne() {
SysUsers users = this.sysUsersCrudRepository.findOne(5);
System.out.println(users);
List ls = (List) this.sysUsersCrudRepository.findAll();
for (SysUsers sysUsers : ls) {
System.out.println(sysUsers);
}
}
@Test
public void TestSysUsersCrudRepositoryDel() {
this.sysUsersCrudRepository.delete(4);
}
} 注意：在试用CrudRepository接口的时候无需自己添加@Transactional回滚，因为CrudRepository为需要添加事务的方法已经添加了事务。
六、PagingAndSortRepository接口使用
pagingAndSortRepository接口，提供了分页与排序的操作，注意：该接口集成了CrudRepository接口。
- 编写接口
public interface SysUsersPagingAndSortRepository extends PagingAndSortingRepository {
}
- 编写测试类
@RunWith(SpringJUnit4ClassRunner.class)
@SpringBootTest(classes = AppStart.class)
public class RepositoryTest {
@Autowired
private SysUsersPagingAndSortRepository sysUsersPagingAndSortRepository;
@Test
public void TestSysUsersPagingAndSortRepositorySort() {
Order order = new Order(Direction.DESC, "id"); // 定义排序规则
Sort sort = new Sort(order); // 封装了排序的规则
Iterable ls = this.sysUsersPagingAndSortRepository.findAll(sort);
for (SysUsers sysUsers : ls) {
System.out.println(sysUsers);
}
}
@Test
public void TestSysUsersPagingAndSortRepositoryPaging() {
// Pageable:封装了分页的参数：当前页，每页显示的条数，注意：他的当前也开始数
// Pageable pageable = new PageRequest(page, size, sort);
// page：当前页 ，size ：每页显示的条数，sort： 排序
Order order = new Order(Direction.DESC, "id"); // 定义排序规则
Sort sort = new Sort(order); // 封装了排序的规则
Pageable pageable = new PageRequest(0, 2, sort);
Page page = this.sysUsersPagingAndSortRepository.findAll(pageable);
System.out.println("总条数：" + page.getTotalElements());
System.out.println("总页数：" + page.getTotalPages());
List ls = page.getContent();
for (SysUsers sysUsers : ls) {
System.out.println(sysUsers);
}
}
} 七、JpaRepository 接口使用
JpaRepository接口特点：该接口集成PagingAndSortingRepository接口，该接口对继承的父接口中方法的返回值进行适配。
- 编写接口
public interface SysUsersJpaRepository extends JpaRepository {
/**
* Repository
*
* T:当前需要映射的实体。 ID:当前映射实体中ID的类型
*/
} - 编写测试类
@RunWith(SpringJUnit4ClassRunner.class)
@SpringBootTest(classes = AppStart.class)
public class RepositoryTest {
@Autowired
private SysUsersJpaRepository sysUsersJpaRepository;
@Test
public void TestSysUsersJpaRepository() {
Order order = new Order(Direction.DESC, "id");
Sort sort = new Sort(order);
List ls = this.sysUsersJpaRepository.findAll(sort);
for (SysUsers sysUsers : ls) {
System.out.println(sysUsers);
}
}
} 八、JPASpecificationExecutor接口的使用
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分页和排序。
注意：
JPASpecificationExecutor接口单独存在,完全独立。使用时需配合其他接口使用。
- 编写接口
public interface SysUserJPASpecificationExecutor extends JpaSpecificationExecutor, JpaRepository {
} - 编写测试类
@RunWith(SpringJUnit4ClassRunner.class)
@SpringBootTest(classes = AppStart.class)
public class RepositoryTest {
@Autowired
private SysUserJPASpecificationExecutor sysUserJPASpecificationExecutor;
/**
* 单条件查询
*/
@Test
public void TestSysUsersJpaRepository() {
/**
* Specification:用户封装查询条件。
*/
Specification spec = new Specification() {
@Override
public Predicate toPredicate(Root root, CriteriaQuery query, CriteriaBuilder cb) {
/**
* Predicate: 封装了单个查询条件； root： 查询对象属性的封装。
* query:封装了要查询中的各个部分的信息（eg：select from order by） cb：查询条件的构造器
*/
// where name = 'Lucy'
Predicate pre = cb.equal(root.get("name"), "LucyLily");
return pre;
}
};
List ls = this.sysUserJPASpecificationExecutor.findAll(spec);
for (SysUsers user : ls) {
System.out.println(user);
}
}
/**
* 多条件查询
*/
@Test
public void TestSysUsersJpaRepository2() {
Specification spec = new Specification() {
@Override
public Predicate toPredicate(Root root, CriteriaQuery query, CriteriaBuilder cb) {
// where name = ? and age = ?
List list = new ArrayList<>();
list.add(cb.equal(root.get("name"), "LucyLily"));
list.add(cb.equal(root.get("age"), 12));
Predicate[] arr = new Predicate[list.size()];
return cb.and(list.toArray(arr)); // cb.or(list.toArray(arr));
/**
* 第二种多条件方式
*/
// return cb.and(cb.equal(root.get("name"), "LucyLily"),cb.equal(root.get("age"), 12));
}
};
Sort sort = new Sort(new Order(Direction.DESC, "id"));
List ls = this.sysUserJPASpecificationExecutor.findAll(spec, sort);
for (SysUsers user : ls) {
System.out.println(user);
}
}
} 九、关联映射操作
1、一对多的关联关系
需求：角色与用户一对多的关联关系
角色：一方
用户：多方
- 创建实体类 SysUsers.java与SysRoles.java
@Entity
@Table(name = "sys_users")
public class SysUsers {
@Id
@GeneratedValue(strategy = GenerationType.IDENTITY)
@Column(name = "id")
private Integer id;
@Column(name = "name")
private String name;
@Column(name = "age")
private Integer age;
@Column(name = "addr")
private String addr;
@ManyToOne
@JoinColumn(name = "rolesId")
private SysRoles sysRoles;
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 getAddr() {
return addr;
}
public void setAddr(String addr) {
this.addr = addr;
}
public SysRoles getSysRoles() {
return sysRoles;
}
public void setSysRoles(SysRoles sysRoles) {
this.sysRoles = sysRoles;
}
}@Entity
@Table(name = "sys_roles")
public class SysRoles {
@Id
@GeneratedValue(strategy = GenerationType.IDENTITY)
@Column(name = "rolesId")
private Integer rolesId;
@Column(name = "rolesName")
private String rolesName;
@OneToMany(mappedBy = "sysRoles")
private Set sysUsers = new HashSet<>();
public Integer getRolesId() {
return rolesId;
}
public void setRolesId(Integer rolesId) {
this.rolesId = rolesId;
}
public String getRolesName() {
return rolesName;
}
public void setRolesName(String rolesName) {
this.rolesName = rolesName;
}
public Set getSysUsers() {
return sysUsers;
}
public void setSysUsers(Set sysUsers) {
this.sysUsers = sysUsers;
}
} - 测试一对多的关联关系（编写测试类）
@RunWith(SpringJUnit4ClassRunner.class)
@SpringBootTest(classes = AppStart.class)
public class RepositoryTest {
@Autowired
private SysUsersJpaRepository sysUsersJpaRepository;
@Test
public void TestOneToManyAdd() {
// 创建一个用户
SysUsers user = new SysUsers();
user.setAddr("AA....");
user.setAge(30);
user.setName("AAAAAA");
// 创建一个角色
SysRoles role = new SysRoles();
role.setRolesName("超级管理员");
// 用户角色关联
role.getSysUsers().add(user);
user.setSysRoles(role);
// 保存
sysUsersJpaRepository.save(user);
}
@Test
public void TestOneToManyQuery() {
SysUsers user = sysUsersJpaRepository.findOne(8);
System.out.println(user);
System.out.println(user.getSysRoles().getRolesName());
}
}2、多对多的关联关系
需求：角色与菜单多对多的关联关系
- 编写实体类SysRoles.java与Menus.java
@Entity
@Table(name = "sys_roles")
public class SysRoles {
@Id
@GeneratedValue(strategy = GenerationType.IDENTITY)
@Column(name = "rolesId")
private Integer rolesId;
@Column(name = "rolesName")
private String rolesName;
@OneToMany(mappedBy = "sysRoles")
private Set sysUsers = new HashSet<>();
@ManyToMany(cascade = CascadeType.PERSIST, fetch = FetchType.EAGER)
// @JoinTable映射中间表
// JoinColumn 当前表的主键所关联中间表中的外键字段
// inverseJoinColumns
@JoinTable(name = "sys_roles_menus", joinColumns = @JoinColumn(name = "rolesId"), inverseJoinColumns = @JoinColumn(name = "menusId"))
private Set roles = new HashSet();
public Integer getRolesId() {
return rolesId;
}
public void setRolesId(Integer rolesId) {
this.rolesId = rolesId;
}
public String getRolesName() {
return rolesName;
}
public void setRolesName(String rolesName) {
this.rolesName = rolesName;
}
public Set getSysUsers() {
return sysUsers;
}
public void setSysUsers(Set sysUsers) {
this.sysUsers = sysUsers;
}
@Override
public String toString() {
return "SysRoles [rolesId=" + rolesId + ", rolesName=" + rolesName + "]";
}
} - 编写测试类
@RunWith(SpringJUnit4ClassRunner.class)
@SpringBootTest(classes = AppStart.class)
public class RepositoryTest {
@Autowired
private SysUsersJpaRepository sysUsersJpaRepository;
@Test
public void TestManyToManyAdd() {
// 创建一个角色
SysRoles sysRoles = new SysRoles();
sysRoles.setRolesName("项目经理");
// 创建菜单
Menus menu = new Menus();
menu.setMenusName("系统管理");
menu.setPid(0);
Menus menu2 = new Menus();
menu2.setMenusName("基础管理");
menu2.setPid(1);
// 关联
sysRoles.getMenus().add(menu);
sysRoles.getMenus().add(menu2);
menu.getRoles().add(sysRoles);
menu2.getRoles().add(sysRoles);
// 保存
this.sysUsersJpaRepository.save(sysRoles);
}
@Test
public void TestManyToManyQuery() {
SysRoles roles = this.sysUsersJpaRepository.findOne(2);
System.out.println(roles);
Set set = roles.getMenus();
for (Menus m : set) {
System.out.println(m);
}
}
}