spring-samples-for-all/spring-boot/spring-boot-data-jpa

spring boot data jpa

一、说明

1.1 项目结构

1.2 项目主要依赖

<dependencies>
   <!-- data-jpa -->
    <dependency>
        <groupId>org.springframework.boot</groupId>
        <artifactId>spring-boot-starter-data-jpa</artifactId>
    </dependency>
    <!--引入mysql驱动-->
    <dependency>
        <groupId>mysql</groupId>
        <artifactId>mysql-connector-java</artifactId>
        <version>8.0.13</version>
    </dependency>
     <!--单元测试包-->
    <dependency>
        <groupId>org.springframework.boot</groupId>
        <artifactId>spring-boot-starter-test</artifactId>
        <scope>test</scope>
    </dependency>
</dependencies>

二、data jpa 的使用

2.1 在application.yml 中配置数据源

spring:
  datasource:
    url: jdbc:mysql://127.0.0.1:3306/mysql?characterEncoding=UTF-8&serverTimezone=UTC&useSSL=false
    username: root
    password: root
    driver-class-name: com.mysql.cj.jdbc.Driver
  jpa:
    hibernate:
      ddl-auto: update
    #Hibernate默认创建的表是myisam引擎，可以用以下方式指定为使用innodb创建表
    database-platform: org.hibernate.dialect.MySQL57Dialect
    show-sql: true

2.2 新建查询接口

/**
 * @author : heibaiying
 * @description : 查询接口继承自CrudRepository,CrudRepository 默认定义了部分增删改查方法
 */
public interface ProgRepository extends CrudRepository<Programmer, Integer> {

    /*
     * 方法名遵循命名规范的查询 更多命名规范可以参考官方文档所列出的这张表格
     */
    List<Programmer> findAllByName(String name);

    /*
     *分页排序查询
     */
    Page<Programmer> findAll(Pageable pageable);


    /*
     * 占位符查询
     */
    @Query(value = "select u from Programmer u where u.name = ?1 or u.salary =  ?2")
    List<Programmer> findByConditionAndOrder(String name, float salary, Sort.Order order);


    /*
     * 传入参数名称
     */
    @Query("select u from Programmer u where u.name = :name or u.age = :age")
    Programmer findByParam(@Param("name") String name,
                           @Param("age") int age);
}

关于查询方法遵循的命名规范和关键词见下表:

Keyword	Sample	JPQL snippet
And	findByLastnameAndFirstname	… where x.lastname = ?1 and x.firstname = ?2
Or	findByLastnameOrFirstname	… where x.lastname = ?1 or x.firstname = ?2
Is,Equals	findByFirstname,findByFirstnameIs, findByFirstnameEquals	… where x.firstname = ?1
Between	findByStartDateBetween	… where x.startDate between ?1 and ?2
LessThan	findByAgeLessThan	… where x.age < ?1
LessThanEqual	findByAgeLessThanEqual	… where x.age <= ?1
GreaterThan	findByAgeGreaterThan	… where x.age > ?1
GreaterThanEqual	findByAgeGreaterThanEqual	… where x.age >= ?1
After	findByStartDateAfter	… where x.startDate > ?1
Before	findByStartDateBefore	… where x.startDate < ?1
IsNull	findByAgeIsNull	… where x.age is null
IsNotNull,NotNull	findByAge(Is)NotNull	… where x.age not null
Like	findByFirstnameLike	… where x.firstname like ?1
NotLike	findByFirstnameNotLike	… where x.firstname not like ?1
StartingWith	findByFirstnameStartingWith	… where x.firstname like ?1(parameter bound with appended %)
EndingWith	findByFirstnameEndingWith	… where x.firstname like ?1(parameter bound with prepended %)
Containing	findByFirstnameContaining	… where x.firstname like ?1(parameter bound wrapped in %)
OrderBy	findByAgeOrderByLastnameDesc	… where x.age = ?1 order by x.lastname desc
Not	findByLastnameNot	… where x.lastname <> ?1
In	findByAgeIn(Collection<Age> ages)	… where x.age in ?1
NotIn	findByAgeNotIn(Collection<Age> ages)	… where x.age not in ?1
True	findByActiveTrue()	… where x.active = true
False	findByActiveFalse()	… where x.active = false
IgnoreCase	findByFirstnameIgnoreCase	… where UPPER(x.firstame) = UPPER(?1)

2.3 测试类

@RunWith(SpringRunner.class)
@SpringBootTest
public class DataJPATests {

    @Autowired
    private ProgRepository repository;

    /**
     * 保存数据测试
     */
    @Test
    public void save() {
        // 保存单条数据
        repository.save(new Programmer("pro01", 12, 2121.34f, new Date()));
        // 保存多条数据
        List<Programmer> programmers = new ArrayList<>();
        programmers.add(new Programmer("pro02", 22, 3221.34f, new Date()));
        programmers.add(new Programmer("pro03", 32, 3321.34f, new Date()));
        programmers.add(new Programmer("pro04", 44, 4561.34f, new Date()));
        programmers.add(new Programmer("pro01", 44, 4561.34f, new Date()));
        repository.saveAll(programmers);
    }


    /**
     * 查询数据测试
     */
    @Test
    public void get() {

        // 遵循命名规范的查询
        List<Programmer> programmers = repository.findAllByName("pro01");
        programmers.forEach(System.out::println);

        // 传入参数名称
        Programmer param = repository.findByParam("pro02", 22);
        System.out.println("findByParam:" + param);

        // 占位符查询
        List<Programmer> byCondition = repository.findByConditionAndOrder("pro03", 3321.34f, Sort.Order.asc("salary"));
        System.out.println("byCondition:" + byCondition);

        //条件与分页查询 需要注意的是这里的页数是从第0页开始计算的
        Page<Programmer> page = repository.findAll(PageRequest.of(0, 10, Sort.Direction.DESC, "salary"));
        page.get().forEach(System.out::println);
    }


    /**
     * 更新数据测试
     */
    @Test
    public void update() {
        // 保存主键相同的数据就认为是更新操作
        repository.save(new Programmer(1, "updatePro01", 12, 2121.34f, new Date()));
        Optional<Programmer> programmer = repository.findById(1);
        Assert.assertEquals(programmer.get().getName(), "updatePro01");
    }

    /**
     * 删除数据测试
     */
    @Test
    public void delete() {
        Optional<Programmer> programmer = repository.findById(2);
        if (programmer.isPresent()) {
            repository.deleteById(2);
        }
        Assert.assertFalse(programmer.isPresent());
    }
}