springboot整合mybatis详解

mybatis是持久层框架，我们之前学习springboot的使用与数据库进行连接使用的是jdbctemple虽然那个也很方便，但是mybatis也很重要

首先我们要像平常一样构建springboot项目，有启动器，有控制器，有实体类等等

仅仅是多了映射接口和映射文件而已
我所谓的映射接口只是我所理解的真实情况可能会有误差，
接口里定义的方法会在我写的映射配置文件中会有实现方法，
而我的映射配置文件中的方法仅仅考虑sql语句的实现即可，
然后我们就可以对数据库进行增删改查的操作啦

启动器类

package cn.lnfvc;

import org.mybatis.spring.annotation.MapperScan;
import org.springframework.boot.SpringApplication;
import org.springframework.boot.autoconfigure.SpringBootApplication;

@SpringBootApplication
@MapperScan(basePackages = "cn.lnfvc.mapper")
public class App {
    public static void main(String[] args) {
        SpringApplication.run(App.class);
    }
}

实体类

package cn.lnfvc.pojo;

public class Book {
    private Integer id;
    private String name;

    public Integer getId() {
        return id;
    }

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

    public String getName() {
        return name;
    }

    public void setName(String name) {
        this.name = name;
    }
}

映射接口

package cn.lnfvc.mapper;


import cn.lnfvc.pojo.Book;
import org.apache.ibatis.annotations.Mapper;

import java.util.List;
@Mapper
public interface BookMapper {
    List<Book> findAllBooks();
    String addBooks();
    String upData();
    String delete();
}

控制器类

package cn.lnfvc.controller;

import cn.lnfvc.mapper.BookMapper;
import cn.lnfvc.pojo.Book;
import org.springframework.web.bind.annotation.GetMapping;
import org.springframework.web.bind.annotation.RestController;

import javax.annotation.Resource;
import java.util.List;

@RestController
public class BookController {
    @Resource
    private BookMapper bookMapper;
    @GetMapping("/books")
    public List<Book> findAllBooks(){
        return bookMapper.findAllBooks();
    }
    @GetMapping("/add")
    public String addBooks(){
        bookMapper.addBooks();
        return "success";
    }
    @GetMapping("/upDate")
    public String upData(){
        bookMapper.upData();
        return "success";
    }
    @GetMapping("/delete")
    public String delete(){
        bookMapper.delete();
        return "success again";
    }
}

说在配置文件前
我们的配置文件中是对数据库进行连接配置
和找到映射接口，实现我们想要的方法，

application.yml

mybatis:
#  config-location: classpath:mybatis-config.xml
  mapper-locations: mapping/BookMapper.xml
spring:
  datasource:
    url: jdbc:mysql://localhost:3309/ssa
    driver-class-name: com.mysql.cj.jdbc.Driver
    username: root
    password: 123

mybatis配置文件

<?xml version="1.0" encoding="UTF-8" ?>
<!DOCTYPE mapper
        PUBLIC "-//mybatis.org//DTD Mapper 3.0//EN"
        "http://mybatis.org/dtd/mybatis-3-mapper.dtd">

<mapper namespace="cn.lnfvc.mapper.BookMapper">
    <resultMap id="BookMapper" type="cn.lnfvc.pojo.Book">
        <id property="id" column="id"/>
        <result property="name" column="name"/>
    </resultMap>
    <select id="findAllBooks" resultType="cn.lnfvc.pojo.Book">
        select * from ssa_test
    </select>
    <select id="addBooks" resultType="cn.lnfvc.pojo.Book">
        insert into ssa_test values (15,'ssa')
    </select>
    <select id="upData" resultType="cn.lnfvc.pojo.Book">
        update ssa_test set name = 'is me' where id=15
    </select>
    <select id="delete" resultType="cn.lnfvc.pojo.Book">
        delete from ssa_test where id=15
    </select>

</mapper>

下图是我的项目路径图

路径图