SpringBoot_持久化方案_JPA

忘是亡心i 2021-10-06 03:34 313阅读 0赞

### SpringBoot\_持久化方案\_JPA ###

*  依赖pom.xml
 *  配置文件bootstrap.yml
 *  配置源码

额外需要数据连接池配置提供DataSource对象

# 依赖pom.xml #

<dependency>
    		<groupId>org.springframework.boot</groupId>
    		<artifactId>spring-boot-starter-data-jpa</artifactId>
    	</dependency>

# 配置文件bootstrap.yml #

spring.jpa.properties.hibernate.hbm2ddl.auto=update
    spring.jpa.properties.hibernate.dialect=org.hibernate.dialect.MySQL5InnoDBDialect
    spring.jpa.show-sql= true

# 配置源码 #

@SpringBootApplication
    @EntityScan("com.plxc.domain")//扫描实体类
    public class Main {
    	public static void main(String[] args) throws Exception {
    		SpringApplication.run(Main.class, args);
    	}
    
    }
    
    //DAO层定义示例代码一
    public interface JpaTbUserRepository extends JpaRepository<JpaTbUser, Integer>{
    	@Query(value = "select * from tb_user b where b.mobile=?1", nativeQuery = true)
    	List<JpaTbUser> findList(String username);
    }
    
    //示例代码二、执行原生SQL
    public interface TransactionRepository extends JpaRepository<Transaction, Long> {
        @Query(value ="select * from transaction where id>?1 limit ?2", nativeQuery = true)
        List< Transaction > getTransactions(Integer startIndex, Integer limit);
    }
    
    //示例代码三、
    //①构建PageRequest对象
    Order nameOrder = new Order(Direction.DESC, "sname");
    Order rangeOrder = new Order(Direction.ASC, "rangeMileage");
    List<Order> orders = new ArrayList<Order>();    
    orders.add(nameOrder);//先按线路降序
    orders.add(rangeOrder);//再按里程升序
    Sort sort2 = new Sort(orders);
    Pageable pageable = new PageRequest(pageNum, size, sort2);
    //②分页查询
    public interface UserRepository extends JpaRepository<User, Long> {
    	 @Query(value = "SELECT * FROM USERS WHERE LASTNAME = ?1",
    	 countQuery = "SELECT count(*) FROM USERS WHERE LASTNAME = ?1",nativeQuery = true)
    	 Page<User> findByLastname(String lastname, Pageable pageable);
    }
    
    //示例代码三、使用自定义参数名
    public interface UserRepository extends JpaRepository<User, Long> {
    	@Query("select u from User u where u.firstname = :firstname or u.lastname = :lastname")
    	User findByLastnameOrFirstname(@Param("lastname") String lastname, @Param("firstname") String firstname);
    }
    
    //示例代码四、约定抽象函数的命名
    public interface ResourceRepository extends JpaRepository<Resource, Long> {
    	public List<Resource> findByUrl(String url);
    }
    
    /**
     * 用户实体类
     * 
     * @author vander
     *
     */
    @Data
    @Entity
    @Table(name="tb_user") //指定数据库表名
    @JsonIgnoreProperties(value={"hibernateLazyInitializer","handler","fieldHandler"}) 
    public class JpaTbUser implements Serializable{
    	private static final long serialVersionUID = 1L;
    	@Id
    	//@GeneratedValue( strategy = GenerationType.IDENTITY) //自增主键需配置
    	private long userId;
    	private String username;
    	private String mobile;
    	//@Column(name="pw") //变量并如果跟数据字段不一致需要注解指定
    	private String password;
    	private Date createTime;
    }