spring boot中的crud方式

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;
	}
	
}