1.引入的CrudRepository中的crud等等
2.引入的PagingAndSortingRepository中的crud等等
3.自己写的jdbcTemplate
0.数据库引入和pom.xml
########################################################
###datasource -- 指定mysql数据库连接信息.
########################################################
spring.datasource.url = jdbc:mysql://localhost:3306/test
spring.datasource.username = root
spring.datasource.password = 123
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的配置信息.
########################################################
# 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
<!-- 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>1.引入的CrudRepository中的crud等等
实体类
/**
* 创建了一个实体类。
*
* 如何持久化呢？
*
* 1、使用@Entity进行实体类的持久化操作，当JPA检测到我们的实体类当中有
*
* @Entity 注解的时候，会在数据库中生成对应的表结构信息。
*
*
* 如何指定主键以及主键的生成策略？
*
* 2、使用@Id指定主键.
*
*/
@Entity
public class Cat {
/**
* 使用@Id指定主键.
*
* 使用代码@GeneratedValue(strategy=GenerationType.AUTO)
* 指定主键的生成策略，mysql默认的是自增长。
*
*/
@Id @GeneratedValue(strategy=GenerationType.AUTO)
private int id;//主键.
private String catName;//姓名. cat_name
private int catAge;//年龄. cat_age;
//省略get set
}
controller
package com.kfit.demo.controller;
import javax.annotation.Resource;
import org.springframework.web.bind.annotation.RequestMapping;
import org.springframework.web.bind.annotation.RestController;
import com.kfit.demo.bean.Cat;
import com.kfit.demo.service.CatService;
@RestController
@RequestMapping("/cat")
public class CatController {
@Resource
private CatService catService;
@RequestMapping("/save")
public String save(){
Cat cat = new Cat();
cat.setCatName("jack");
cat.setCatAge(3);
catService.save(cat);
return "save ok.";
}
@RequestMapping("/delete")
public String delete(){
catService.delete(1);
return "delete ok";
}
@RequestMapping("/getAll")
public Iterable<Cat> getAll(){
return catService.getAll();
}
@RequestMapping("/findByCatName")
public Cat findByCatName(String catName){
return catService.findByCatName(catName);
}
@RequestMapping("/findByCatName2")
public Cat findByCatName2(String catName){
System.out.println("CatController.findByCatName2()");
return catService.findByCatName2(catName);
}
@RequestMapping("/selectByCatName")
public Cat selectByCatName(String catName){
return catService.selectByCatName(catName);
}
}
service
package com.kfit.demo.service;
import javax.annotation.Resource;
import javax.transaction.Transactional;
import org.springframework.stereotype.Service;
import com.kfit.demo.bean.Cat;
import com.kfit.demo.dao.CatDao;
import com.kfit.demo.repository.Cat2Repository;
import com.kfit.demo.repository.CatRepository;
@Service
public class CatService {
@Resource
private CatRepository catRepository;
@Resource
private Cat2Repository cat2Repository;
@Resource
private CatDao catDao;
/**
* save,update ,delete 方法需要绑定事务.
*
* 使用@Transactional进行事务的绑定.
*
* @param cat
*/
//保存数据.
@Transactional
public void save(Cat cat){
catRepository.save(cat);
}
//删除数据》
@Transactional
public void delete(int id){
catRepository.delete(id);
}
//查询数据.
public Iterable<Cat> getAll(){
return catRepository.findAll();
}
public Cat findByCatName(String catName){
return cat2Repository.findByCatName(catName);
}
public Cat findByCatName2(String catName){
return cat2Repository.findMyCatName(catName);
}
public Cat selectByCatName(String catName){
return catDao.selectByCatName(catName);
}
}
dao---CrudRepository的使用
package com.kfit.demo.repository;
import org.springframework.data.repository.CrudRepository;
import com.kfit.demo.bean.Cat;
/**
* Repository -- 是接口 ，不是class.
*/
public interface CatRepository extends CrudRepository<Cat, Integer>{
}
dao--PagingAndSortingRepository使用
package com.kfit.demo.repository;
import org.springframework.data.jpa.repository.Query;
import org.springframework.data.repository.PagingAndSortingRepository;
import org.springframework.data.repository.query.Param;
import com.kfit.demo.bean.Cat;
public interface Cat2Repository extends PagingAndSortingRepository<Cat, Integer>{
/**
* 1/ 查询方法 以 get | find | read 开头.
* 2/ 涉及查询条件时，条件的属性用条件关键字连接，要注意的是条件属性以首字母大写。
*/
//根据catName进行查询 : 根据catName进行查询.
public Cat findByCatName(String catName);
/**
* 如何编写JPQL语句，
* Hibernate -- HQL语句.
* JPQL 语句 和HQL语句是类似的.
*/
@Query("from Cat where catName=:cn")
public Cat findMyCatName(@Param("cn")String catName);
}
dao--jdbcTemplate使用
import javax.annotation.Resource;
import org.springframework.jdbc.core.BeanPropertyRowMapper;
import org.springframework.jdbc.core.JdbcTemplate;
import org.springframework.jdbc.core.RowMapper;
import org.springframework.stereotype.Repository;
import com.kfit.demo.bean.Cat;
/**
* 使用@Repository注解，标注这是一个持久化操作对象.
*/
@Repository
public class CatDao {
@Resource
private JdbcTemplate jdbcTemplate;
public Cat selectByCatName(String catName){
/**
* 1、定义一个Sql语句；
* 2、定义一个RowMapper.
* 3、执行查询方法.
*/
String sql = "select *from cat where cat_name=?";
RowMapper<Cat> rowMapper = new BeanPropertyRowMapper<>(Cat.class);
Cat cat = jdbcTemplate.queryForObject(sql, new Object[]{catName}, rowMapper);
return cat;
}
}