Springboot整合mybatis的步骤

前期工作

1.导入mybatis整合依赖

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									<!--   mybatis整合     -->

									<dependency>

									<groupId>org.mybatis.spring.boot</groupId>

									    <artifactId>mybatis-spring-boot-starter</artifactId>

									    <version>2.1.4</version>

									</dependency>

2.连接数据库

3.连接完数据库就去applicaton.yml配置一下数据库

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									spring:

									  datasource:

									    username: root

									    password: 123456

									    url: jdbc:mysql://localhost:3306/mybatis?serverTimezone=UTC&useUnicode=true&characterEncoding=utf-8

									    driver-class-name: com.mysql.cj.jdbc.Driver

开始整合

1.编写与数据库对应的实体类

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									package com.example.pojo;

									import lombok.AllArgsConstructor;

									import lombok.Data;

									import lombok.NoArgsConstructor;

									@Data

									@AllArgsConstructor

									@NoArgsConstructor

									public class User {

									    private Integer id;

									    private String name;

									    private String pwd;

									}

为了偷懒，导入了lombok

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									<!-- lombok     -->

									<dependency>

									    <groupId>org.projectlombok</groupId>

									    <artifactId>lombok</artifactId>

									</dependency>

2.编写mapper

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									package com.example.mapper;

									import com.example.pojo.User;

									import org.apache.ibatis.annotations.Mapper;

									import org.springframework.stereotype.Repository;

									import java.util.List;

									@Mapper

									@Repository

									public interface UserMapper {

									    //查询用户的全部信息

									    List<User> getUserList();

									    //select 找出id=1的用户

									    User getUserById(int id);

									    //insert 增加一个用户

									    int insertUser(User user);

									    //delete 删除id=4的用户

									    int deleteUser(int id);

									    //update 将id=2的用户名字改为小龙

									    int updateUser(User user);

									}

3.编写mapper.xml文件

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									<?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="com.example.mapper.UserMapper">

									    <select id="getUserList" resultType="user">

									        select *

									        from mybatis.user

									    </select>

									    <select id="getUserById" resultType="user" parameterType="int">

									        select *

									        from mybatis.user

									        where id = #{id};

									    </select>

									    <insert id="insertUser" parameterType="user">

									        insert into mybatis.user (id, name, pwd)

									        values (#{id}, #{name}, #{pwd});

									    </insert>

									    <delete id="deleteUser" parameterType="int">

									        delete

									        from mybatis.user

									        where id = #{id};

									    </delete>

									    <update id="updateUser" parameterType="user">

									        update mybatis.user

									        set name = #{name},

									            pwd = #{pwd}

									        where id = #{id};

									    </update>

									</mapper>

这里我们用了别名而且我们把这个mapper.xml文件放在了resources目录下，所以我们要去application.yml配置一下

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									mybatis:

									  type-aliases-package: com.example.pojo

									  mapper-locations: classpath:mybatis/mapper/*.xml

mapper.xml文件编写的位置：

Springboot整合mybatis的步骤

4.编写controller

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									package com.example.controller;

									import com.example.mapper.UserMapper;

									import com.example.pojo.User;

									import org.apache.ibatis.annotations.Param;

									import org.springframework.beans.factory.annotation.Autowired;

									import org.springframework.web.bind.annotation.GetMapping;

									import org.springframework.web.bind.annotation.PathVariable;

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

									import java.util.List;

									@RestController

									public class UserController {

									    @Autowired

									    private UserMapper userMapper;

									    @GetMapping("/getUserList")

									    public List<User> getUserList(){

									        return userMapper.getUserList();

									    }

									    @GetMapping("/getUserById/{id}")

									    public User getUserById(@PathVariable("id") int id){

									        return userMapper.getUserById(id);

									    }

									    @GetMapping("/insertUser")

									    public String insertUser(){

									        userMapper.insertUser(new User(5,"xiaoming","111"));

									        return "ok";

									    }

									    @GetMapping("/deleteUser")

									    public String deleteUser(){

									        userMapper.deleteUser(5);

									        return "ok";

									    }

									    @GetMapping("/updateUser")

									    public String updateUser(){

									        userMapper.updateUser(new User(5,"xx","111"));

									        return "ok";

									    }

									}