springboot-jpa|hibernate|springdata

版权声明：fromZjy QQ1045152332 https://blog.csdn.net/qq_36762677/article/details/83474928

一、Concept

JPA java persistence API
通过5.0的注解或者xml描述对象到关系表的映射关系,并将运行期的实体对象持久化到数据库中
Hibernate
jpa是一种规范,hibernate是它的实现
对jdbc轻量级封装,将pojo与数据库表建立映射关系,全自动orm框架
springData
简化对数据库访问,支持云服务的开源框架
springDataJpa
是springData的一个模块, 简化jpa的写法,除了curd外,还有分页、排序功能,只需要实现一个接口就可以curd操作

二、springboot+jpa

1.add pom dependencies

	<!-- 添加MySQL数据库驱动依赖包. -->
	<dependency>
		<groupId>mysql</groupId>
		<artifactId>mysql-connector-java</artifactId>
	</dependency>
	<!-- 添加Spring-data-jpa依赖. -->
	<dependency>
	    <groupId>org.springframework.boot</groupId>
	    <artifactId>spring-boot-starter-data-jpa</artifactId>
	</dependency>

2.Add database configuration information in application.properties

########################################################
###datasource config
########################################################
spring.datasource.url = jdbc:mysql://localhost:3306/test
spring.datasource.username = root
spring.datasource.password = root
spring.datasource.driverClassName = com.mysql.jdbc.Driver
spring.datasource.max-active=20
spring.datasource.max-idle=8
spring.datasource.min-idle=8
spring.datasource.initial-size=10


########################################################
### Java Persistence Api --  Spring jpa config
########################################################
# Specify the DBMS
spring.jpa.database = MYSQL
# Show or not log for each sql query
spring.jpa.show-sql = true
# Hibernate ddl auto (create, create-drop, update)
spring.jpa.hibernate.ddl-auto = update
# Naming strategy
#[org.hibernate.cfg.ImprovedNamingStrategy  #org.hibernate.cfg.DefaultNamingStrategy]
spring.jpa.hibernate.naming-strategy = org.hibernate.cfg.ImprovedNamingStrategy
# stripped before adding them to the entity manager)
spring.jpa.properties.hibernate.dialect = org.hibernate.dialect.MySQL5Dialect

3.Entity class

@Entity//标注实体类
@Id//主键
@GeneratedValue(Strategy=GenerationType.AUTO)//主键生成策略

4.Reponsitory interface

//最顶层空接口Reponstory
public interface XxxReponsitory extends CurdReponsitory<Xxx,Integer>{
	//已经继承了curd接口的所有方法

	//可以两种方法自定义查询
	//1.查询方法以find,get,read开头
	public Xxx findByXxxName(String xxxName);
	//2.JPQL语句 类似hql
	@Query("from Xxx where xxxName = :na);
	public Xxx findByXxxName2(@Params("na" String xxxName);
}

in service

@Autowired
private XxxReponsitory xxxReponsitory;

@Transaction//进行事务绑定

xxxReponsitory.save(Xxx);
xxxReponsitory.delete(1)
List<Xxx> list = xxxReponsitory.findAll();

三、springboot + jdbcTemplate

1.add pom dependencies

	<!-- 添加MySQL数据库驱动依赖包. -->
	<dependency>
		<groupId>mysql</groupId>
		<artifactId>mysql-connector-java</artifactId>
	</dependency>
	<!-- 添加Spring-data-jdbc依赖. -->
	<!-- 当然,如何已经加入jpa,则不用引入jdbc-->
	<dependency>
	    <groupId>org.springframework.boot</groupId>
	    <artifactId>spring-boot-starter-data-jdbc</artifactId>
	</dependency>

2.Method of use

@Reponsitory
public class DemoDao{
	@Resource
	private JdbcTemplate jdbcTemplate;
	
	public Demo getById(long id){
		String sql = "select * from Demo where id=?";
		RowMapper<Demo> rowMapper = new BeanPropertyRowMapper<Demo>(Demo.class);
		return jdbcTemplate.queryForObject(sql,rowMapper);
	}
}