SpringBoot整合MyBatis超详细教程

目录1.整合MyBatis操作1.1.配置模式1.2.注解模式1.3.混合模式

1.整合MyBatis操作

前面一篇提到了SpringBoot整合基础的数据源JDBC、Druid操作,实际项目中更常用的还是MyBatis框架,而SpringBoot整合MyBatis进行CRUD也非常方便。

下面从配置模式、注解模式、混合模式三个方面进行说明MyBatis与SpringBoot的整合。

1.1.配置模式

MyBatis配置模式是指使用mybatis配置文件的方式与SpringBoot进行整合,相对应的就有mybatis-config.xml(用于配置驼峰命名,也可以省略这个文件)、XxxMapper.xml文件。

主要步骤为:

导入mybatis官方starter 编写mapper接口。标准@Mapper注解 编写sql映射文件并绑定mapper接口

在application.yaml中指定Mapper配置文件的位置,以及指定全局配置文件的信息 (建议;配置在mybatis.configuration中,可以省略mybatis-config.xml文件)

下面是具体整合配置步骤:

①引入相关依赖pom.xml配置:

pom.xml

<dependencies>        <dependency>            <groupId>org.springframework.boot</groupId>            <artifactId>spring-boot-starter-web</artifactId>        </dependency>        <!--整合mybatis-->        <dependency>            <groupId>org.mybatis.spring.boot</groupId>            <artifactId>mybatis-spring-boot-starter</artifactId>            <version>2.1.4</version>        </dependency>        <dependency>            <groupId>mysql</groupId>            <artifactId>mysql-connector-java</artifactId>            <scope>runtime</scope>        </dependency>        <dependency>            <groupId>org.springframework.boot</groupId>            <artifactId>spring-boot-devtools</artifactId>            <scope>runtime</scope>            <optional>true</optional>        </dependency>        <dependency>            <groupId>org.projectlombok</groupId>            <artifactId>lombok</artifactId>            <optional>true</optional>        </dependency>        <dependency>            <groupId>org.springframework.boot</groupId>            <artifactId>spring-boot-starter-test</artifactId>            <scope>test</scope>        </dependency>    </dependencies>    <build>        <plugins>            <plugin>                <groupId>org.springframework.boot</groupId>                <artifactId>spring-boot-maven-plugin</artifactId>                <configuration>                    <excludes>                        <exclude>                            <groupId>org.projectlombok</groupId>                            <artifactId>lombok</artifactId>                        </exclude>                    </excludes>                </configuration>            </plugin>        </plugins>    </build>

②编写对应Mapper接口:

@Mapper  //这个注解表示了这个类是一个mybatis的mapper接口类@Repositorypublic interface UserMapper {    //@Select("select * from user")    List<User> findAllUsers();    //@Insert("insert into user(id, username, password) values (#{id}, #{username}, #{password})")    void insert(User user);    //@Update("update user set username = #{username}, password = #{password} where id = #{id}")    void update(User user);    //@Delete("delete from user where id = #{id}")    void deleteById(Integer id);}

③在resources下创建对应的mapper文件,对应domain类,数据库表单如下:

User类:

@Datapublic class User {    private Integer id;    private String username;    private String password;}

数据库user表:

UserMapper.xml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"><!--namespace表示当前mapper的唯一标识:一般使用domain的全路径名+Mapper来命名--><mapper namespace="com.fengye.springboot_mybatis.mapper.UserMapper">    <!--id:方法表示,一般配置对应的方法;        resultType:表示该方法有返回,返回需要封装到对应实体的类型-->    <select id="findAllUsers" resultType="com.fengye.springboot_mybatis.entity.User">        select * from user    </select>    <insert id="insert" parameterType="com.fengye.springboot_mybatis.entity.User">        insert into user(id, username, password) values (#{id}, #{username}, #{password})    </insert>    <update id="update" parameterType="com.fengye.springboot_mybatis.entity.User">        update user set username = #{username}, password = #{password} where id = #{id}    </update>    <delete id="deleteById" parameterType="Integer">        delete from user where id = #{id}    </delete></mapper>

④对应配置application.yml文件:

application.yml

server:  port: 8083spring:  datasource:    username: root    password: admin    #假如时区报错,增加时区配置serverTimezone=UTC    url: jdbc:mysql://localhost:3306/mybatis02_0322?serverTimezone=UTC&useUnicode=true&characterEncoding=utf-8    driver-class-name: com.mysql.cj.jdbc.Drivermybatis:  #config-location: classpath:mybatis/mybatis-config.xml  使用了configuration注解则无需再指定mybatis-config.xml文件  mapper-locations: classpath:mybatis/mapper/*.xml  configuration:   #指定mybatis全局配置文件中的相关配置项    map-underscore-to-camel-case: true

1.2.注解模式

注解模式使用

主要步骤:

导入mybatis官方依赖 注解方式编写mapper接口 在application.yaml中指定Mapper配置文件的位置,以及指定全局配置文件的信息

可以看到注解模式比配置模式少了编写Mapper.xml文件,简化了简单SQL语句的xml文件编写。

下面是具体整合步骤:

①创建测试表单city,对应domain类:

建表sql:

CREATE TABLE city(    id    INT(11) PRIMARY KEY AUTO_INCREMENT,    name VARCHAR(30),    state VARCHAR(30),    country VARCHAR(30));

City类:

@Datapublic class City {    private Long id;    private String name;    private String state;    private String country;}

②导入pom.xml与配置模式相同,编写注解式CityMapper接口:

@Mapper@Repositorypublic interface CityMapper {    @Select("select * from city where id = #{id}")    public City getCityById(Long id);    /**     * 使用@Options来增加除Insert语句中其它可选参数,比如插入获取id主键的值     * @param city     */    @Insert("insert into city(name, state, country) values (#{name}, #{state}, #{country})")    @Options(useGeneratedKeys = true, keyProperty = "id")    public void insert(City city);    @Update("update city set name = #{name}, state = #{state}, country = #{country} where id = #{id}")    public void update(City city);    @Delete("delete from city where id = #{id}")    public void deleteById(Long id);}

③编写Service层、Controller层:

Service相关:

public interface CityService {    City findCityById(Long id);    void insert(City city);    void update(City city);    void deleteById(Long id);}@Servicepublic class CityServiceImpl implements CityService {    @Autowired    private CityMapper cityMapper;    @Override    public City findCityById(Long id) {        return cityMapper.getCityById(id);    }    @Override    public void insert(City city) {        cityMapper.insert(city);    }    @Override    public void update(City city) {        cityMapper.update(city);    }    @Override    public void deleteById(Long id) {        cityMapper.deleteById(id);    }}

Controller相关:

@RestController@RequestMapping("/city/api")public class CityController {    @Autowired    private CityService cityService;    @RequestMapping("/findCityById/{id}")    public City findCityById(@PathVariable("id") Long id){        return cityService.findCityById(id);    }    @PostMapping("/insert")    public String insert(City city){        cityService.insert(city);        return "insert ok";    }    @PostMapping("/update")    public String update(City city){        cityService.update(city);        return "update ok";    }    @GetMapping("/delete/{id}")    public String delete(@PathVariable("id") Long id){        cityService.deleteById(id);        return "delete ok";    }}

④对应使用Postman接口进行测试:

简单模拟接口POST/GET请求即可:

1.3.混合模式

在实际项目开发中涉及很多复杂业务及连表查询SQL,可以配合使用注解与配置模式,达到最佳实践的目的。

实际项目操作步骤:

引入mybatis-starter 配置application.yaml中,指定mapper-location位置即可 编写Mapper接口并标注@Mapper注解 简单方法直接注解方式 复杂方法编写mapper.xml进行绑定映射 主启动类上使用@MapperScan(“com.fengye.springboot_mybatis.mapper”) 简化Mapper接口,包下所有接口就可以不用标注@Mapper注解

具体配置如下:

@SpringBootApplication//主启动类上标注,在XxxMapper中可以省略@Mapper注解@MapperScan("com.fengye.springboot_mybatis.mapper")public class SpringbootMybatisApplication {    public static void main(String[] args) {        SpringApplication.run(SpringbootMybatisApplication.class, args);    }}@Repositorypublic interface CityMapper {    @Select("select * from city where id = #{id}")    public City getCityById(Long id);    /**     * 使用@Options来增加除Insert语句中其它可选参数,比如插入获取id主键的值     * @param city     */    @Insert("insert into city(name, state, country) values (#{name}, #{state}, #{country})")    @Options(useGeneratedKeys = true, keyProperty = "id")    public void insert(City city);    @Update("update city set name = #{name}, state = #{state}, country = #{country} where id = #{id}")    public void update(City city);    @Delete("delete from city where id = #{id}")    public void deleteById(Long id);}

本博客参考写作文档:

SpringBoot2核心技术与响应式编程

博客涉及代码示例均已上传至github地址:

SpringBootStudy

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