springboot集成mybatis

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前言

springboot整合mybatis

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一、创建User数据表

CREATE TABLE restaurant.`user` (
	id int auto_increment NOT NULL COMMENT '主键',
	name varchar(20) NULL COMMENT '姓名',
	age int NULL COMMENT '年龄',
	sex char(1) NULL COMMENT '性别 0 男 1 女',
	create_time DATETIME NULL COMMENT '创建时间',
	CONSTRAINT user_pk PRIMARY KEY (id)
)
ENGINE=InnoDB
DEFAULT CHARSET=utf8
COLLATE=utf8_general_ci;

添加任意条数据
数据库相关内容创建完毕

二、导入Mybatis的Maven坐标

		<dependency>
			<groupId>org.mybatis.spring.bootgroupId>
			<artifactId>mybatis-spring-boot-starterartifactId>
			<version>3.0.2version>
		dependency>

项目基于springboot3.x
其他依赖包

		
		<dependency>
			<groupId>org.springframework.bootgroupId>
			<artifactId>spring-boot-starter-webartifactId>
		dependency>
		
		<dependency>
			<groupId>com.mysqlgroupId>
			<artifactId>mysql-connector-jartifactId>
			<version>8.0.33version>
		dependency>
		
		<dependency>
			<groupId>org.projectlombokgroupId>
			<artifactId>lombokartifactId>
			<optional>trueoptional>
		dependency>
		
		<dependency>
			<groupId>cn.hutoolgroupId>
			<artifactId>hutool-allartifactId>
			<version>5.8.20version>
		dependency>

配置application.yml文件

# 数据源配置
spring:
  datasource:
    driverClassName: com.mysql.cj.jdbc.Driver
    # 数据库地址
    url: jdbc:mysql://你的数据库地址:3306/restaurant?useUnicode=true&characterEncoding=utf8&zeroDateTimeBehavior=convertToNull&useSSL=true&serverTimezone=GMT%2B8
    username: 你的数据库用户名
    password: 你的数据库密码
  jackson:
    property-naming-strategy: SNAKE_CASE # 小驼峰规则配置
    default-property-inclusion: non_null # 序列化非null的属性
mybatis:
  type-aliases-package: com.ndky.**.domain
  mapper-locations: classpath*:mapper/**/*Mapper.xml
server:
  port: 8088

三、编写实体类,service代码和mapper代码

代码如下：
实体User类

package com.ndky.helloworld.domain;

import lombok.Data;

import java.time.LocalDateTime;

/**
 * @author LikeYouDo
 * @date 2023/10/22 10:42
 */
@Data//使用lomok简化实体类代码,这里不再展开
public class User {
    private Integer id;
    private String name;
    private Integer age;
    private String sex;
    private LocalDateTime createTime;
}

Mapper接口

package com.ndky.helloworld.mapper;

/**
 * @author LikeYouDo
 * @date 2023/10/22 11:41
 */
 //可以通过使用注解@Mapper
 //或者在Application启动类中添加注解扫描mapper包的方式扫描Mapper
 //这里使用第二种
public interface UserMapper {
}

在Application类中添加@MapperScan扫描包路径

package com.ndky.mybatisdemo;

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

@SpringBootApplication
@MapperScan("com.ndky.mybatisdemo.mapper")  // +++
public class MybatisDemoApplication {

	public static void main(String[] args) {
		SpringApplication.run(MybatisDemoApplication.class, args);
	}

}

IUserService业务接口及其实现类

package com.ndky.mybatisdemo.service;

/**
 * @author LikeYouDo
 * @date 2023/10/22 11:47
 */
public interface IUserService {
}

package com.ndky.mybatisdemo.service.impl;

import com.ndky.mybatisdemo.service.IUserService;
import org.springframework.stereotype.Service;

/**
 * @author LikeYouDo
 * @date 2023/10/22 11:48
 */
@Service
public class UserServiceImpl implements IUserService {
}

四、实现编写业务逻辑和mybatis文件

mybatis的xml用法不再赘述,可以跳转学习

1.在controller层中编写请求uri方法

package com.ndky.mybatisdemo.controller;

import com.ndky.mybatisdemo.domain.User;
import com.ndky.mybatisdemo.service.IUserService;
import org.springframework.beans.factory.annotation.Autowired;
import org.springframework.web.bind.annotation.*;

/**
 * @author LikeYouDo
 * @date 2023/10/12 15:17
 */

@RestController
@RequestMapping("/hello")
public class MybatisController {

    @Autowired
    private IUserService userService;

    /**
     * 获取所有数据
     *
     * @return
     */
    @GetMapping()
    public String getUsers() {
        return userService.getUsers();
    }

    /**
     * 根据id查询数据
     *
     * @param id
     * @return
     */
    @GetMapping("/{id}")
    public String getUserById(@PathVariable("id") Integer id) {
        return userService.getUserById(id);
    }

    /**
     * 添加一个新的数据
     *
     * @param user
     * @return
     */
    @PostMapping()
    public String postHello(@RequestBody User user) {
        return userService.insertUser(user);
    }

    /**
     * 根据id修改name
     *
     * @param user
     * @return
     */
    @PutMapping()
    public String updateUser(@RequestBody User user) {
        return userService.updateUser(user);
    }

    /**
     * 根据id删除数据
     * @param id
     * @return
     */
    @DeleteMapping("/{id}")
    public String deleteUserById(@PathVariable Integer id) {
        return userService.deleteUserById(id);
    }

}

2.编写业务逻辑代码

package com.ndky.mybatisdemo.service;

import com.ndky.mybatisdemo.domain.User;

/**
 * @author LikeYouDo
 * @date 2023/10/22 11:47
 */
public interface IUserService {
    String getUsers();

    String getUserById(Integer id);

    String insertUser(User user);

    String updateUser(User user);

    String deleteUserById(Integer id);
}

package com.ndky.mybatisdemo.service.impl;

import com.ndky.mybatisdemo.domain.User;
import com.ndky.mybatisdemo.mapper.UserMapper;
import com.ndky.mybatisdemo.service.IUserService;
import org.springframework.beans.factory.annotation.Autowired;
import org.springframework.stereotype.Service;

/**
 * @author LikeYouDo
 * @date 2023/10/22 11:48
 */
@Service
public class UserServiceImpl implements IUserService {
    
    @Autowired
    private UserMapper userMapper;
    
    @Override
    public String getUsers() {
        return userMapper.selectUsers();
    }

    @Override
    public String getUserById(Integer id) {
        User user = userMapper.selectUserById(id);
        return user==null?"没有查询到该用户":user.toString();
    }

    @Override
    public String insertUser(User user) {
        return userMapper.insertUser(user);
    }

    @Override
    public String updateUser(User user) {
        return userMapper.updateUser(user);
    }

    @Override
    public String deleteUserById(Integer id) {
        return userMapper.deleteUserById(id);
    }
}

3.编写UserMapper中对应xml的sql语句

package com.ndky.mybatisdemo.mapper;


import com.ndky.mybatisdemo.domain.User;
import org.apache.ibatis.annotations.Mapper;

/**
 * @author LikeYouDo
 * @date 2023/10/22 11:41
 */
@Mapper
public interface UserMapper {
    String selectUsers();

    String selectUserById(Integer id);

    String insertUser(User user);

    String updateUser(User user);

    String deleteUserById(Integer id);
}

DOCTYPE mapper
        PUBLIC "-//mybatis.org//DTD Mapper 3.0//EN"
        "http://mybatis.org/dtd/mybatis-3-mapper.dtd">
<mapper namespace="com.ndky.mybatisdemo.mapper.UserMapper">
    <resultMap id="UserResult" type="User">
        <id property="id" column="id"/>
        <result property="name" column="name"/>
        <result property="age" column="age" />
        <result property="sex" column="sex" />
        <result property="createTime" column="create_time" />
    resultMap>
    <insert id="insertUser" parameterType="user">
        insert into user(name,age,sex,create_time) values(#{name},#{age},#{sex},#{createTime})
    insert>
    <update id="updateUser" parameterType="user">
        update user set name=#{name},age=#{age},sex=#{sex},create_time=#{createTime} where id=#{id}
    update>
    <delete id="deleteUserById">
        delete from user where id = #{id}
    delete>

    <select id="selectUsers" resultMap="UserResult">
        select * from user
    select>
    <select id="selectUserById" parameterType="integer" resultMap="UserResult">
        select * from user where id = #{id}
    select>
mapper>

接口调用测试

查询所有user

根据id查询user
添加一个user


检测是否添加成功

修改数据

删除数据

PS: 关于LocalDateTime时间类

对于时间的LocalDateTime类因为格式问题jackson无法进行数据转换,需要进行相关序列化配置

package com.ndky.mybatisdemo.config;

import com.fasterxml.jackson.databind.DeserializationFeature;
import com.fasterxml.jackson.databind.ObjectMapper;
import com.fasterxml.jackson.datatype.jsr310.JavaTimeModule;
import com.fasterxml.jackson.datatype.jsr310.deser.LocalDateDeserializer;
import com.fasterxml.jackson.datatype.jsr310.deser.LocalDateTimeDeserializer;
import com.fasterxml.jackson.datatype.jsr310.deser.LocalTimeDeserializer;
import com.fasterxml.jackson.datatype.jsr310.ser.LocalDateSerializer;
import com.fasterxml.jackson.datatype.jsr310.ser.LocalDateTimeSerializer;
import com.fasterxml.jackson.datatype.jsr310.ser.LocalTimeSerializer;
import org.springframework.context.annotation.Bean;
import org.springframework.context.annotation.Configuration;
 
import java.time.LocalDate;
import java.time.LocalDateTime;
import java.time.LocalTime;
import java.time.format.DateTimeFormatter;
 
/**
 * 日期序列化
 *
 * @author kou
 */
@Configuration
public class LocalDateTimeSerializerConfig {
 
    @Bean(name = "mapperObject")
    public ObjectMapper getObjectMapper() {
        ObjectMapper om = new ObjectMapper();
        JavaTimeModule javaTimeModule = new JavaTimeModule();
 
        // 序列化
        javaTimeModule.addSerializer(LocalDateTime.class, new LocalDateTimeSerializer(DateTimeFormatter.ofPattern("yyyy-MM-dd HH:mm:ss")));
        javaTimeModule.addSerializer(LocalDate.class, new LocalDateSerializer(DateTimeFormatter.ofPattern("yyyy-MM-dd")));
        javaTimeModule.addSerializer(LocalTime.class, new LocalTimeSerializer(DateTimeFormatter.ofPattern("HH:mm:ss")));
 
        // 反序列化
        javaTimeModule.addDeserializer(LocalDateTime.class, new LocalDateTimeDeserializer(DateTimeFormatter.ofPattern("yyyy-MM-dd HH:mm:ss")));
        javaTimeModule.addDeserializer(LocalDate.class, new LocalDateDeserializer(DateTimeFormatter.ofPattern("yyyy-MM-dd")));
        javaTimeModule.addDeserializer(LocalTime.class, new LocalTimeDeserializer(DateTimeFormatter.ofPattern("HH:mm:ss")));
 
        om.registerModule(javaTimeModule);
        // 或略不识别的字段
        om.configure(DeserializationFeature.FAIL_ON_UNKNOWN_PROPERTIES, false);
        return om;
    }
 
}

配置后,修改前
修改后(可以正常接受yyyy-MM-dd HH:mm:ss格式的参数了,但是返回值还是会带T需要前端进行处理)

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总结。

以上就是对mybatis的简单使用,对mybatis使用熟悉后,可以进行进阶学习MP(MybatisPlus)或者MF(MybatisFlex)来提升开发效率