SpringBoot_JPA
-
创建SpringBoot工程：springboot_jpa
-
生成项目的pom文件：
<?xml version="1.0" encoding="UTF-8"?>
<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 https://maven.apache.org/xsd/maven-4.0.0.xsd">
<modelVersion>4.0.0</modelVersion>
<parent>
<groupId>org.springframework.boot</groupId>
<artifactId>spring-boot-starter-parent</artifactId>
<version>2.2.6.RELEASE</version>
<relativePath/> <!-- lookup parent from repository -->
</parent>
<groupId>com.example</groupId>
<artifactId>springboot_jpa</artifactId>
<version>0.0.1-SNAPSHOT</version>
<name>springboot_jpa</name>
<description>Demo project for Spring Boot</description>
<properties>
<java.version>1.8</java.version>
</properties>
<dependencies>
<dependency>
<groupId>org.springframework.boot</groupId>
<artifactId>spring-boot-starter-data-jpa</artifactId>
</dependency>
<dependency>
<groupId>org.springframework.boot</groupId>
<artifactId>spring-boot-starter-web</artifactId>
</dependency>
<dependency>
<groupId>mysql</groupId>
<artifactId>mysql-connector-java</artifactId>
<scope>runtime</scope>
</dependency>
<dependency>
<groupId>org.springframework.boot</groupId>
<artifactId>spring-boot-starter-test</artifactId>
<scope>test</scope>
<exclusions>
<exclusion>
<groupId>org.junit.vintage</groupId>
<artifactId>junit-vintage-engine</artifactId>
</exclusion>
</exclusions>
</dependency>
</dependencies>
<build>
<plugins>
<plugin>
<groupId>org.springframework.boot</groupId>
<artifactId>spring-boot-maven-plugin</artifactId>
</plugin>
</plugins>
</build>
</project>
- 添加lombok依赖
<dependency>
<groupId>org.projectlombok</groupId>
<artifactId>lombok</artifactId>
<scope>provided</scope>
</dependency>
- 把application.properties改成application.yml，添加配置内容：
#数据库连接
spring:
datasource:
url: jdbc:mysql://localhost:3306/test?characterEncoding=UTF-8&serverTimezone=GMT%2B8
username: root
password: 123456
driver-class-name: com.mysql.cj.jdbc.Driver
jpa:
show-sql: true #在控制台中打印sql
- 数据库表employee表结构和内容：
表结构：
主键id自动递增
表内容：
6. 数据库表department表结构和内容：
表结构：
表内容：
7. Employee实体类
package com.example.demo.entity;
import javax.persistence.Column;
import javax.persistence.Entity;
import javax.persistence.GeneratedValue;
import javax.persistence.GenerationType;
import javax.persistence.Id;
import javax.persistence.Table;
import lombok.Data;
import lombok.ToString;
@Data
@ToString
@NoArgsConstructor
@AllArgsConstructor
@Entity //告诉JPA这是一个要和数据库表映射的实体类
@Table(name="employee") //用于指定和数据库中的哪个表映射
public class Employee {
@Id //标识主键
@GeneratedValue(strategy = GenerationType.IDENTITY) //设置主键增长类型
private Integer id;
@Column(name = "last_name") //指定属性和数据库中的哪个字段映射
private String lastName;
@Column
private String email;
@Column
private Integer gender;
@Column(name = "d_id")
private Integer departmentId;
}
- EmployeeRepository接口
package com.example.demo.repos;
import org.springframework.data.jpa.repository.JpaRepository;
import com.example.demo.entity.Employee;
/**
* 自定义Repository，继承JpaRepository
* 泛型1：要处理的实体类
* 泛型2：主键的类型
*
* @author BLU
*/
public interface EmployeeRepository extends JpaRepository<Employee, Integer>{
}
- 测试类SpringbootJpaApplicationTests
package com.example.demo;
import java.util.Optional;
import org.junit.jupiter.api.Test;
import org.springframework.beans.factory.annotation.Autowired;
import org.springframework.boot.test.context.SpringBootTest;
import com.example.demo.entity.Employee;
import com.example.demo.repos.EmployeeRepository;
@SpringBootTest
class SpringbootJpaApplicationTests {
@Autowired
EmployeeRepository er;
@Test
public void test_findbyId() {
Optional<Employee> optional = er.findById(3);
System.out.println(optional);
}
}
- 运行test_findbyId()，控制台打印：
Hibernate: select employee0_.id as id1_0_0_, employee0_.d_id as d_id2_0_0_, employee0_.email as email3_0_0_, employee0_.gender as gender4_0_0_, employee0_.last_name as last_nam5_0_0_ from employee employee0_ where employee0_.id=?
Optional[Employee(id=3, lastName=BLU, [email protected], gender=1, departmentId=1)]
- 保存单个数据
@Test
public void test_save1() {
Employee e = new Employee(null, "amy", "[email protected]", 2, 1);
er.save(e);
}
控制台打印：
Hibernate: insert into employee (d_id, email, gender, last_name) values (?, ?, ?, ?)
数据库增加了一条记录：
12. 保存多个数据
@Test
public void test_save2() {
Employee e1 = new Employee(null, "amy1", "[email protected]", 2, 1);
Employee e2 = new Employee(null, "amy2", "[email protected]", 2, 1);
Employee e3 = new Employee(null, "amy3", "[email protected]", 2, 1);
er.saveAll(Arrays.asList(e1,e2,e3));
}
控制台打印：
Hibernate: insert into employee (d_id, email, gender, last_name) values (?, ?, ?, ?)
Hibernate: insert into employee (d_id, email, gender, last_name) values (?, ?, ?, ?)
Hibernate: insert into employee (d_id, email, gender, last_name) values (?, ?, ?, ?)
数据库增加了3条记录：
13. 修改数据
注：添加和修改调用的都是save方法，区别是添加方法传入的id为空，修改方法传入的id为要修改的记录的id
@Test
public void test_modify() {
Employee e = new Employee(1, "zs", "[email protected]", 2, 1);
er.save(e);
}
控制台打印：
Hibernate: select employee0_.id as id1_0_0_, employee0_.d_id as d_id2_0_0_, employee0_.email as email3_0_0_, employee0_.gender as gender4_0_0_, employee0_.last_name as last_nam5_0_0_ from employee employee0_ where employee0_.id=?
Hibernate: update employee set d_id=?, email=?, gender=?, last_name=? where id=?
数据库中的第一条记录被修改了：
14. 删除记录
@Test
public void test_delete() {
er.deleteById(9);
}
控制台打印：
Hibernate: select employee0_.id as id1_0_0_, employee0_.d_id as d_id2_0_0_, employee0_.email as email3_0_0_, employee0_.gender as gender4_0_0_, employee0_.last_name as last_nam5_0_0_ from employee employee0_ where employee0_.id=?
Hibernate: delete from employee where id=?
数据库中的第9条记录被删除了
15. 查询全部数据
@Test
public void test_findAll() {
List<Employee> list = er.findAll();
for(Employee e : list) {
System.out.println(e);
}
}
控制台打印：
Hibernate: select employee0_.id as id1_0_, employee0_.d_id as d_id2_0_, employee0_.email as email3_0_, employee0_.gender as gender4_0_, employee0_.last_name as last_nam5_0_ from employee employee0_
Employee(id=1, lastName=zs, [email protected], gender=2, departmentId=1)
Employee(id=2, lastName=lisi, [email protected], gender=1, departmentId=1)
Employee(id=3, lastName=BLU, [email protected], gender=1, departmentId=1)
Employee(id=4, lastName=linda, email=linda.qq.com, gender=2, departmentId=1)
Employee(id=5, lastName=ruby, [email protected], gender=2, departmentId=1)
Employee(id=6, lastName=amy, [email protected], gender=2, departmentId=1)
Employee(id=7, lastName=amy1, [email protected], gender=2, departmentId=1)
Employee(id=8, lastName=amy2, [email protected], gender=2, departmentId=1)
- 查询多个数据
@Test
public void test_findAllById() {
List<Employee> list = er.findAllById(Arrays.asList(2,3,4));
for(Employee e : list) {
System.out.println(e);
}
}
控制台打印：
Hibernate: select employee0_.id as id1_0_, employee0_.d_id as d_id2_0_, employee0_.email as email3_0_, employee0_.gender as gender4_0_, employee0_.last_name as last_nam5_0_ from employee employee0_ where employee0_.id in (? , ? , ?)
Employee(id=2, lastName=lisi, [email protected], gender=1, departmentId=1)
Employee(id=3, lastName=BLU, [email protected], gender=1, departmentId=1)
Employee(id=4, lastName=linda, email=linda.qq.com, gender=2, departmentId=1)
- 分页查询
@Test
public void test_page() {
PageRequest pageRequest = PageRequest.of(0, 3);
Page<Employee> page = er.findAll(pageRequest);
System.out.println("totalpages"+page.getTotalPages());
List<Employee> list = page.getContent();
for(Employee e : list) {
System.out.println(e);
}
}
控制台打印：
Hibernate: select employee0_.id as id1_0_, employee0_.d_id as d_id2_0_, employee0_.email as email3_0_, employee0_.gender as gender4_0_, employee0_.last_name as last_nam5_0_ from employee employee0_ limit ?
Hibernate: select count(employee0_.id) as col_0_0_ from employee employee0_
totalpages3
Employee(id=1, lastName=zs, [email protected], gender=2, departmentId=1)
Employee(id=2, lastName=lisi, [email protected], gender=1, departmentId=1)
Employee(id=3, lastName=BLU, [email protected], gender=1, departmentId=1)
- 排序查询（按id和gender逆序排序）
注：这里Order要导入的包为：import org.springframework.data.domain.Sort.Order;
@Test
public void test_sort() {
Order o_id = new Order(Direction.DESC,"id");
Order o_gender = new Order(Direction.DESC,"gender");
Sort sort = Sort.by(o_id,o_gender);
List<Employee> list = er.findAll(sort);
for(Employee e : list) {
System.out.println(e);
}
}
控制台打印：
Hibernate: select employee0_.id as id1_0_, employee0_.d_id as d_id2_0_, employee0_.email as email3_0_, employee0_.gender as gender4_0_, employee0_.last_name as last_nam5_0_ from employee employee0_ order by employee0_.id desc, employee0_.gender desc
Employee(id=8, lastName=amy2, [email protected], gender=2, departmentId=1)
Employee(id=7, lastName=amy1, [email protected], gender=2, departmentId=1)
Employee(id=6, lastName=amy, [email protected], gender=2, departmentId=1)
Employee(id=5, lastName=ruby, [email protected], gender=2, departmentId=1)
Employee(id=4, lastName=linda, email=linda.qq.com, gender=2, departmentId=1)
Employee(id=3, lastName=BLU, [email protected], gender=1, departmentId=1)
Employee(id=2, lastName=lisi, [email protected], gender=1, departmentId=1)
Employee(id=1, lastName=zs, [email protected], gender=2, departmentId=1)
- 自定义接口EmployeeDao继承Repository
package com.example.demo.repos;
import org.springframework.data.repository.Repository;
import com.example.demo.entity.Employee;
/**
* 自定义Repository，继承JpaRepository
* 泛型1：要处理的实体类
* 泛型2：主键的类型
*
* @author BLU
*/
public interface EmployeeDao extends Repository<Employee, Integer>{
}
- 在测试类中注入EmployeeDao
@Autowired
EmployeeDao eDao;
- 在EmployeeDao接口中添加方法：
//根据id查询
Employee findById(Integer id);
//根据lastName查询
Employee findByLastName(String uname);
- findById测试方法：
@Test
public void test_eDao_findById() {
Employee e = eDao.findById(3);
System.out.println(e);
}
控制台打印：
Hibernate: select employee0_.id as id1_0_0_, employee0_.d_id as d_id2_0_0_, employee0_.email as email3_0_0_, employee0_.gender as gender4_0_0_, employee0_.last_name as last_nam5_0_0_ from employee employee0_ where employee0_.id=?
Employee(id=3, lastName=BLU, [email protected], gender=1, departmentId=1)
- findByLastName方法：
@Test
public void test_eDao_findByLastName() {
Employee e = eDao.findByLastName("linda");
System.out.println(e);
}
控制台打印：
Hibernate: select employee0_.id as id1_0_, employee0_.d_id as d_id2_0_, employee0_.email as email3_0_, employee0_.gender as gender4_0_, employee0_.last_name as last_nam5_0_ from employee employee0_ where employee0_.last_name=?
Employee(id=4, lastName=linda, email=linda.qq.com, gender=2, departmentId=1)
- 符合SpringData方法定义规范的写法示例：
findByLastName
...where x.lastname = ?1
findByLastnameAndFirstname
...where x.lastname = ?1 and x.firstname = ?2
findByLastnameOrFirstname
...where x.lastname = ?1 or x.firstname = ?2
findByIdBetween
...where x.id between ?1 and ?2
findByAgeLessThan
...where x.age < ?1
findByAgeLessThanEqual
...where x.age <= ?1
findByAgeGreaterThan
...where x.age > ?1
findByAgeGreaterThanEqual
...where x.age >= ?1
findByAgeIsNull
...where x.age is null
findByAgeIsNotNull
...where x.age not null
findByLastNameLike
...where x.lastname like ?1
findByLastNameNotLike
...where x.lastname not like ?1
findByAgeOrderByLastnameDesc
...where x.age = ?1 order by x.lastname desc
findByLastNameNot
...where x.lastname <> ?1
findByAgeIn
...where x.age in ?1
findByAgeNotIn
...where x.age not in ?1
findByActiveTrue
...where x.active = true
findByActiveFalse
...where x.active = false
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