Java框架_SpringBoot整合Spring Data JPA 转载:https://blog.csdn.net/lxp18850413505/article/details/80987550

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

<project xmlns="http://maven.apache.org/POM/4.0.0" xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance" xsi:schemaLocation="http://maven.apache.org/POM/4.0.0 http://maven.apache.org/xsd/maven-4.0.0.xsd">
   <modelVersion>4.0.0</modelVersion>
   <groupId>com.lxp</groupId>
   <artifactId>framework</artifactId>
   <version>0.0.1-SNAPSHOT</version>

   
   <parent>
       <groupId>org.springframework.boot</groupId>
       <artifactId>spring-boot-starter-parent</artifactId>
       <version>1.5.10.RELEASE</version>
   </parent>

   <properties>
       <java.version>1.7</java.version>
   </properties>

   
   <dependencies>

       
<dependency>
<groupId>org.springframework.boot</groupId>
<artifactId>spring-boot-starter-web</artifactId>
</dependency>


<dependency>
<groupId>org.springframework.boot</groupId>
<artifactId>spring-boot-starter-test</artifactId>
</dependency>

   
       <dependency>
           <groupId>mysql</groupId>
           <artifactId>mysql-connector-java</artifactId>
       </dependency>

   
<dependency>
   <groupId>com.alibaba</groupId>
<artifactId>druid</artifactId>
<version>1.0.9</version>
   </dependency>

   
       <dependency>
           <groupId>org.springframework.boot</groupId>
           <artifactId>spring-boot-starter-data-jpa</artifactId>
       </dependency>

</dependencies>
</project>
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 = true
4、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<SysUsers, Integer> {

   /**
   * JpaRepository<T,ID>
   *
   * 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<SysUsers, Integer> {

   /**
   * 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<SysUsers> findByName(String name);

   // 多条件（and）
   List<SysUsers> findByNameAndAge(String name, int age);

   // 多条件（or）
   List<SysUsers> findByNameOrAge(String name, int age);

   // 单条件（like）
   List<SysUsers> 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<SysUsers> ls = this.sysUsersRepository.findByName("Lucy");
       for (SysUsers sysUsers : ls) {
           System.out.println(sysUsers);
       }

       List<SysUsers> 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<SysUsers> ls = this.sysUsersRepository.findByNameAndAge("Lucy", 12);
       for (SysUsers sysUsers : ls) {
           System.out.println(sysUsers);
       }

       List<SysUsers> 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<SysUsers, Integer> {

   // 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<SysUsers> 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<SysUsers> 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<SysUsers> ls = this.sysUsersRepositoryQueryAnnotation.QueryByNameHQL("Lucy");
       for (SysUsers sysUsers : ls) {
           System.out.println(sysUsers);
       }

       List<SysUsers> 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<SysUsers, Integer> {
    /**
   * 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<SysUsers> ls = (List<SysUsers>) 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<SysUsers, Integer> {

}
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<SysUsers> 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<SysUsers> page = this.sysUsersPagingAndSortRepository.findAll(pageable);

       System.out.println("总条数：" + page.getTotalElements());
       System.out.println("总页数：" + page.getTotalPages());

       List<SysUsers> 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<SysUsers, Integer> {

   /**
   * Repository<T,ID>
   *
   * 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<SysUsers> 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<SysUsers>, JpaRepository<SysUsers, Integer> {

}
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<SysUsers>:用户封装查询条件。
       */
       Specification<SysUsers> spec = new Specification<SysUsers>() {
           @Override
           public Predicate toPredicate(Root<SysUsers> 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<SysUsers> ls = this.sysUserJPASpecificationExecutor.findAll(spec);
       for (SysUsers user : ls) {
           System.out.println(user);
       }
   }

   /**
   * 多条件查询
   */
   @Test
   public void TestSysUsersJpaRepository2() {
       Specification<SysUsers> spec = new Specification<SysUsers>() {
           @Override
           public Predicate toPredicate(Root<SysUsers> root, CriteriaQuery<?> query, CriteriaBuilder cb) {
               // where name = ? and age = ?

               List<Predicate> 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<SysUsers> 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> 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<SysUsers> getSysUsers() {
       return sysUsers;
   }

   public void setSysUsers(Set<SysUsers> 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> 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<Menus> 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<SysUsers> getSysUsers() {
       return sysUsers;
   }

   public void setSysUsers(Set<SysUsers> 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<Menus> set = roles.getMenus();
       for (Menus m : set) {
           System.out.println(m);
       }

   }
}

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