206 lines
9.5 KiB
Markdown
206 lines
9.5 KiB
Markdown
# Spring Boot Data JPA
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<nav>
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<a href="#一项目说明">一、项目说明</a><br/>
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<a href="#11-项目结构">1.1 项目结构</a><br/>
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<a href="#12-基本依赖">1.2 基本依赖</a><br/>
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<a href="#二-使用-Data-JPA">二、 使用 Data JPA</a><br/>
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<a href="#21-数据源配置">2.1 数据源配置</a><br/>
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<a href="#22-查询接口">2.2 查询接口</a><br/>
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<a href="#23--单元测试">2.3 单元测试</a><br/>
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</nav>
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## 一、项目说明
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### 1.1 项目结构
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<div align="center"> <img src="https://github.com/heibaiying/spring-samples-for-all/blob/master/pictures/spring-boot-data-jpa.png"/> </div>
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### 1.2 基本依赖
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```xml
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<dependencies>
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<!-- data-jpa -->
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<dependency>
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<groupId>org.springframework.boot</groupId>
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<artifactId>spring-boot-starter-data-jpa</artifactId>
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</dependency>
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<!--引入 mysql 驱动-->
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<dependency>
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<groupId>mysql</groupId>
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<artifactId>mysql-connector-java</artifactId>
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<version>8.0.13</version>
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</dependency>
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<!--单元测试包-->
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<dependency>
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<groupId>org.springframework.boot</groupId>
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<artifactId>spring-boot-starter-test</artifactId>
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<scope>test</scope>
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</dependency>
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</dependencies>
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```
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## 二、 使用 Data JPA
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### 2.1 数据源配置
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在 application.yml 中配置数据源：
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```yaml
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spring:
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datasource:
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url: jdbc:mysql://127.0.0.1:3306/mysql?characterEncoding=UTF-8&serverTimezone=UTC&useSSL=false
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username: root
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password: root
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driver-class-name: com.mysql.cj.jdbc.Driver
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jpa:
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hibernate:
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ddl-auto: update
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#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
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database-platform: org.hibernate.dialect.MySQL57Dialect
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show-sql: true
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```
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### 2.2 查询接口
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```java
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/**
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* @description : 查询接口继承自 CrudRepository,CrudRepository 默认定义了部分增删改查方法
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*/
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public interface ProgRepository extends CrudRepository<Programmer, Integer> {
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/*
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* 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
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*/
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List<Programmer> findAllByName(String name);
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/*
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*分页排序查询
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*/
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Page<Programmer> findAll(Pageable pageable);
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/*
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* 占位符查询
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*/
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@Query(value = "select u from Programmer u where u.name = ?1 or u.salary = ?2")
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List<Programmer> findByConditionAndOrder(String name, float salary, Sort.Order order);
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/*
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* 传入参数名称
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*/
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@Query("select u from Programmer u where u.name = :name or u.age = :age")
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Programmer findByParam(@Param("name") String name,
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@Param("age") int age);
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}
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```
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在使用 Spring Data JPA 时你甚至可以不用写 SQL 语句，只需要在定义方法名时满足 Spring 的规范即可，Spring 会自动将这些方法按照其命名转换为对应的 SQL 语句，以下是其转换对照表：
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| Keyword | Sample | JPQL snippet |
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| ------------------- | ------------------------------------------------------------ | ------------------------------------------------------------ |
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| `And` | `findByLastnameAndFirstname` | `… where x.lastname = ?1 and x.firstname = ?2` |
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| `Or` | `findByLastnameOrFirstname` | `… where x.lastname = ?1 or x.firstname = ?2` |
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| `Is,Equals` | `findByFirstname`,`findByFirstnameIs`,<br>`findByFirstnameEquals` | `… where x.firstname = ?1` |
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| `Between` | `findByStartDateBetween` | `… where x.startDate between ?1 and ?2` |
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| `LessThan` | `findByAgeLessThan` | `… where x.age < ?1` |
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| `LessThanEqual` | `findByAgeLessThanEqual` | `… where x.age <= ?1` |
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| `GreaterThan` | `findByAgeGreaterThan` | `… where x.age > ?1` |
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| `GreaterThanEqual` | `findByAgeGreaterThanEqual` | `… where x.age >= ?1` |
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| `After` | `findByStartDateAfter` | `… where x.startDate > ?1` |
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| `Before` | `findByStartDateBefore` | `… where x.startDate < ?1` |
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| `IsNull` | `findByAgeIsNull` | `… where x.age is null` |
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| `IsNotNull,NotNull` | `findByAge(Is)NotNull` | `… where x.age not null` |
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| `Like` | `findByFirstnameLike` | `… where x.firstname like ?1` |
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| `NotLike` | `findByFirstnameNotLike` | `… where x.firstname not like ?1` |
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| `StartingWith` | `findByFirstnameStartingWith` | `… where x.firstname like ?1`(parameter bound with appended `%`) |
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| `EndingWith` | `findByFirstnameEndingWith` | `… where x.firstname like ?1`(parameter bound with prepended `%`) |
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| `Containing` | `findByFirstnameContaining` | `… where x.firstname like ?1`(parameter bound wrapped in `%`) |
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| `OrderBy` | `findByAgeOrderByLastnameDesc` | `… where x.age = ?1 order by x.lastname desc` |
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| `Not` | `findByLastnameNot` | `… where x.lastname <> ?1` |
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| `In` | `findByAgeIn(Collection<Age> ages)` | `… where x.age in ?1` |
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| `NotIn` | `findByAgeNotIn(Collection<Age> ages)` | `… where x.age not in ?1` |
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| `True` | `findByActiveTrue()` | `… where x.active = true` |
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| `False` | `findByActiveFalse()` | `… where x.active = false` |
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| `IgnoreCase` | `findByFirstnameIgnoreCase` | `… where UPPER(x.firstame) = UPPER(?1)` |
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### 2.3 单元测试
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```java
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@RunWith(SpringRunner.class)
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@SpringBootTest
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public class DataJPATests {
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@Autowired
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private ProgRepository repository;
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/**
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* 保存数据测试
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*/
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@Test
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public void save() {
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// 保存单条数据
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repository.save(new Programmer("pro01", 12, 2121.34f, new Date()));
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// 保存多条数据
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List<Programmer> programmers = new ArrayList<>();
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programmers.add(new Programmer("pro02", 22, 3221.34f, new Date()));
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programmers.add(new Programmer("pro03", 32, 3321.34f, new Date()));
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programmers.add(new Programmer("pro04", 44, 4561.34f, new Date()));
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programmers.add(new Programmer("pro01", 44, 4561.34f, new Date()));
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repository.saveAll(programmers);
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}
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/**
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* 查询数据测试
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*/
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@Test
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public void get() {
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// 遵循命名规范的查询
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List<Programmer> programmers = repository.findAllByName("pro01");
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programmers.forEach(System.out::println);
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// 传入参数名称
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Programmer param = repository.findByParam("pro02", 22);
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System.out.println("findByParam:" + param);
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// 占位符查询
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List<Programmer> byCondition = repository.findByConditionAndOrder("pro03", 3321.34f, Sort.Order.asc("salary"));
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System.out.println("byCondition:" + byCondition);
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//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
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Page<Programmer> page = repository.findAll(PageRequest.of(0, 10, Sort.Direction.DESC, "salary"));
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page.get().forEach(System.out::println);
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}
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/**
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* 更新数据测试
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*/
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@Test
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public void update() {
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// 保存主键相同的数据就认为是更新操作
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repository.save(new Programmer(1, "updatePro01", 12, 2121.34f, new Date()));
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Optional<Programmer> programmer = repository.findById(1);
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Assert.assertEquals(programmer.get().getName(), "updatePro01");
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}
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/**
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* 删除数据测试
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*/
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@Test
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public void delete() {
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Optional<Programmer> programmer = repository.findById(2);
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if (programmer.isPresent()) {
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repository.deleteById(2);
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}
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Assert.assertFalse(programmer.isPresent());
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}
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}
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```
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