SpringBoot整合MyBatis SpringBoot整合MyBatis超详细教程
人无名,则可专心练剑 人气:01.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 @Repository public 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:
@Data public 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: 8083 spring: 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.Driver mybatis: #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:
@Data public 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 @Repository public 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); } @Service public 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); } } @Repository public 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); }
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