Spring boot之JdbcTemplate

实体类

package com.kfit.demo1.bean;

import javax.persistence.Entity;
import javax.persistence.GeneratedValue;
import javax.persistence.GenerationType;
import javax.persistence.Id;

/**
 * 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;

    public int getId() {
        return id;
    }

    public void setId(int id) {
        this.id = id;
    }

    public String getCatName() {
        return catName;
    }

    public void setCatName(String catName) {
        this.catName = catName;
    }

    public int getCatAge() {
        return catAge;
    }

    public void setCatAge(int catAge) {
        this.catAge = catAge;
    }

}

DAO类

package com.kfit.demo1.dao;

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.demo1.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;
    }

}

repository类

package com.kfit.demo1.repository;

import org.springframework.data.repository.CrudRepository;

import com.kfit.demo1.bean.Cat;

/**
 * Repository -- 是接口 ，不是class.
 */
public interface CatRepository extends CrudRepository<Cat, Integer>{

}

package com.kfit.demo1.repository;

import org.springframework.data.jpa.repository.Query;
import org.springframework.data.repository.PagingAndSortingRepository;
import org.springframework.data.repository.query.Param;

import com.kfit.demo1.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);
}

service类

package com.kfit.demo1.service;

import javax.annotation.Resource;
import javax.transaction.Transactional;

import org.springframework.stereotype.Service;

import com.kfit.demo1.bean.Cat;

import com.kfit.demo1.repository.CatRepository;
import com.kfit.demo1.dao.CatDao;
import com.kfit.demo1.repository.Cat2Repository;

@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);
    }
}

controller类

package com.kfit.demo1.controller;

import javax.annotation.Resource;

import org.springframework.web.bind.annotation.RequestMapping;
import org.springframework.web.bind.annotation.RestController;

import com.kfit.demo1.bean.Cat;
import com.kfit.demo1.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);
    }
}