springboot-5-整合jpa
######## ##springboot-parent.version: 1.5.2 ## jdk 1.8 ## #######
在整合jpa之前, 先说下mysql
步骤:
1), 在application.properties中加入datasource配置
2), 在pom.xml中加入mysql依赖
3), 获取datasource的connection测试
然后, 配置连接池为druid
1), pom.xml中引入依赖
<dependency>
<groupId>com.alibaba</groupId>
<artifactId>druid</artifactId>
<version>1.0.18</version>
</dependency>
2), 配置application.properties数据源类型
3), 编写druid servlet和filter提供监控页面访问
jpa, 是一种规范, hibernate是他的一种实现方式
jpa是一种关于数据操作的 orm 对象/关系映射规范
1, 引入依赖
<!-- 整合jpa使用 -->
<dependency>
<groupId>org.springframework.boot</groupId>
<artifactId>spring-boot-starter-data-jpa</artifactId>
</dependency>
<!-- Spring Boot JDBC -->
<dependency>
<groupId>org.springframework.boot</groupId>
<artifactId>spring-boot-starter-jdbc</artifactId>
</dependency>
<!--mysql驱动 -->
<dependency>
<groupId>mysql</groupId>
<artifactId>mysql-connector-java</artifactId>
</dependency>
2, 在src/main/source创建配置文件
application.yml
##### jpa ####### spring: datasource: url: jdbc:mysql://localhost:3306/test username: root password: 123 driver-class-name: com.mysql.jdbc.Driver jpa: database: MYSQL show-sql: true hibernate: ddl-auto: update # naming: # implicit-strategy: org.hibernate.cfg.ImprovedNamingStrategy properties: # 默认 hibernate: dialect: org.hibernate.dialect.MySQL5Dialect
3, 在实体类上加入@Entity, 就可以进行crud操作了
package com.iwhere.test.demo; 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 javax.validation.constraints.NotNull;
// 生成表结构 @Entity
// 表名, 不写默认为类名 @Table(name="demo") public class Demo {
// 主键 @Id
// 主键生成策略 @GeneratedValue(strategy=GenerationType.AUTO) private Integer id; @NotNull private String name; @Column(nullable=false) private String sex; public Integer getId() { return id; } public void setId(int id) { this.id = id; } public String getName() { return name; } public void setName(String name) { this.name = name; } public String getSex() { return sex; } public void setSex(String sex) { this.sex = sex; } public void setId(Integer id) { this.id = id; } }
4, dao层继承接口即可
package com.iwhere.test.dao; import org.springframework.data.repository.CrudRepository; import com.iwhere.test.demo.Demo; /** * 使用crud接口的dao层 * @author 231 * */ public interface DemoRepository extends CrudRepository<Demo, Long> { }
5, service层调用
package com.iwhere.test.service; import javax.annotation.Resource; import org.springframework.stereotype.Service; import org.springframework.transaction.annotation.Transactional; import com.iwhere.test.dao.DemoRepository; import com.iwhere.test.demo.Demo; /** * service层 * @author 231 */ @Service public class DemoService { @Resource private DemoRepository demoRepository; @Transactional public void save(Demo demo) { demoRepository.save(demo); } }
6, controller层执行
package com.iwhere.test.web; import javax.annotation.Resource; import org.springframework.web.bind.annotation.RequestMapping; import org.springframework.web.bind.annotation.RestController; import com.iwhere.test.demo.Demo; import com.iwhere.test.service.DemoService; @RestController @RequestMapping("/demo") public class DemoController { @Resource private DemoService demoService; /** * 返回json格式数据 * @RestController * @return */ @RequestMapping("/getDemo") public Demo getDemo() { Demo demo = new Demo(); demo.setId(1); demo.setName("Angel"); return demo; } /** * 测试jpa的使用 * @return */ @RequestMapping("/save") public String saveDemo() { Demo demo = new Demo(); demo.setId(1); demo.setName("Angel"); demo.setSex("female"); demoService.save(demo); return "ok"; }
/**测试自定义异常*/ // @RequestMapping("/zeroExcetpion") // public int zeroException() { // System.err.println("zero"); // return 1/0; // } }
此时运行, 既可以在数据库看到demo的存入了
然后, 介绍下repository接口:
1, 空接口, 标记
2, 继承Repository接口后, 会被IOC容器识别为一个bean
3, 也可用@RepositoryDefinition注解来代替继承
4, 方法名即sql语句
5, 条件树形要用关键字链接
6, 可以使用@Query实现自定义jpql语句
jpa操作为接口操作, 一个方法既一个sql语句, 常见的接口如下表:
具体的关键字，使用方法和生产成SQL如下表所示: 原文地址: http://www.cnblogs.com/ityouknow/p/5891443.html
| 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 | 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 ages) | … where x.age in ?1 |
| NotIn | findByAgeNotIn(Collection age) | … 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) |
分页查询
分页查询在实际使用中非常普遍了，spring data jpa已经帮我们实现了分页的功能，在查询的方法中，需要传入参数Pageable
,当查询中有多个参数的时候Pageable建议做为最后一个参数传入
Page<User> findALL(Pageable pageable);
Page<User> findByUserName(String userName,Pageable pageable);
Pageable 是spring封装的分页实现类，使用的时候需要传入页数、每页条数和排序规则
@Test public void testPageQuery() throws Exception { int page=1,size=10; Sort sort = new Sort(Direction.DESC, "id"); Pageable pageable = new PageRequest(page, size, sort); userRepository.findALL(pageable); userRepository.findByUserName("testName", pageable); }
