导入相关pom依赖
<dependency>
<groupId>org.springframework.boot</groupId>
<artifactId>spring-boot-starter-data-jpa</artifactId>
</dependency>
application.yml文件配置
spring:
jpa:
hibernate:
ddl-auto: update
show-sql: true
自动建表相关代码
@Entity
@Table(name = "t_springbootjpa_book")
public class Book {
@Id
@GeneratedValue
private Integer bid;
@Column(length = 100)
private String bname;
@Column
private Float price;
jpa值增删改查
* 只要继承JpaRepository,通常所用的增删查改方法都有
* 第一个参数:操作的实体类
* 第二个参数:实体类对应数据表的主键
*/
public interface JpaDao extends JpaRepository<Book, Integer> {
}
controller层
@Autowired
private JpaDao jpaDao;
@RequestMapping("/add")
public String add(Book book){
jpaDao.save(book);
return "success";
}
@RequestMapping("/edit")
public String edit(Book book){
jpaDao.save(book);
return "success";
}
@RequestMapping("/del")
public String del(Book book){
jpaDao.delete(book);
return "success";
}
@RequestMapping("/getOne")
public Book getOne(Integer bid){
// 会出现懒加载问题:org.hibernate.LazyInitializationException: could not initialize proxy - no Session
// return jpaDao.getOne(bid);
return jpaDao.findById(bid).get();
}
@RequestMapping("/getAll")
public List<Book> getAll(){
return jpaDao.findAll();
}
浏览器输入请求进行测试
http://localhost:8080/springboot/jpa/getOne?bid=8
http://localhost:8080/springboot/jpa/getAll
http://localhost:8080/springboot/jpa/add?bname=哈哈ha&price=99
http://localhost:8080/springboot/jpa/add?bname=嗯哼&price=12&bid=11
http://localhost:8080/springboot/jpa/del?bid=11
jpa值复杂查询
dao层
* 要使用高级查询必须继承
* org.springframework.data.jpa.repository.JpaSpecificationExecutor<T>接口
*/
public interface JpaDao extends JpaRepository<Book, Integer>, JpaSpecificationExecutor<Book> {
}
controller层
@RequestMapping("/getCondition")
public List<Book> getCondition(Book book){
return jpaDao.findAll(new Specification<Book>() {
@Override
public Predicate toPredicate(Root<Book> root, CriteriaQuery<?> criteriaQuery, CriteriaBuilder criteriaBuilder) {
Predicate predicate = criteriaBuilder.conjunction();
if(book != null){
if(null != book.getBname() && !"".equals(book.getBname())){
predicate.getExpressions().add(criteriaBuilder.like(root.get("bname"),"%"+book.getBname()+"%"));
}
}
return predicate;
}
});
}