SpringBoot+Mybatis+application.yml（仅供入门参考）

项目目录：

说明，本文中有两个mapper接口，分别采用xml形式和java注解形式实现。

1、项目创建完成后，pom.xml文件配置

<parent>
    <groupId>org.springframework.boot</groupId>
    <artifactId>spring-boot-starter-parent</artifactId>
    <version>2.1.6.RELEASE</version>
</parent>
<dependencies>
    <!-- springboot 整合web组件 整合springmvc-->
    <dependency>
        <groupId>org.springframework.boot</groupId>
        <artifactId>spring-boot-starter-jdbc</artifactId>
    </dependency>
    <dependency>
        <groupId>mysql</groupId>
        <artifactId>mysql-connector-java</artifactId>
        <version>5.1.29</version>
    </dependency>
    <dependency>
        <groupId>com.alibaba</groupId>
        <artifactId>druid</artifactId>
        <version>1.1.0</version>
    </dependency>
    <dependency>
        <groupId>org.springframework.boot</groupId>
        <artifactId>spring-boot-starter-web</artifactId>
    </dependency>
    <dependency>
        <groupId>org.springframework.boot</groupId>
        <artifactId>spring-boot-starter-test</artifactId>
    </dependency>
    <dependency>
        <groupId>org.mybatis.spring.boot</groupId>
        <artifactId>mybatis-spring-boot-starter</artifactId>
        <version>1.3.2</version>
    </dependency>
    <dependency>
            <groupId>org.projectlombok</groupId>
            <artifactId>lombok</artifactId>
            <version>1.18.2</version>
    </dependency>
</dependencies>

2、application.yml配置

spring:
  datasource:
    #   数据源基本配置
    username: root
    password: root
    driver-class-name: com.mysql.jdbc.Driver
    url: jdbc:mysql://localhost:3306/demo
    type: com.alibaba.druid.pool.DruidDataSource

server:
  port: 8888

mybatis:
#在yml文件中做了以下配置就无需做mybatis-config.xml配置，如果使用了mybatis-config.xml配置，就把下面两行注掉，将第三行配置打开
  mapper-locations: classpath:mybatis/mappers/*.xml
  type-aliases-package: com.example.mybatis.entity
  #config-location: classpath:mybatis-config.xml

3、在 resources 下创建个 mybatis-config.xml 内容如下：

<?xml version="1.0" encoding="UTF-8" ?>
<!DOCTYPE configuration
        PUBLIC "-//mybatis.org//DTD Config 3.0//EN"
        "http://mybatis.org/dtd/mybatis-3-config.dtd">
<configuration>
    <!--设置-->
    <settings>
        <!-- 使用全局的映射器启用或者禁用缓存。 -->
        <setting name="cacheEnabled" value="true"/>
        <!-- 这是默认的执行类型 （SIMPLE: 简单； REUSE: 执行器可能重复使用prepared statements语句；BATCH: 执行器可以重复执行语句和批量更新） -->
        <setting name="defaultExecutorType" value="SIMPLE"/>
        <!--  设置驱动等待数据响应的超时数  默认没有设置-->
        <setting name="defaultStatementTimeout" value="30000"/>
        <!-- 使用驼峰命名法转换字段。 -->
        <setting name="mapUnderscoreToCamelCase" value="true"/>
        <!-- 允许JDBC 生成主键。需要驱动器支持。如果设为了true，这个设置将强制使用被生成的主键，有一些驱动器不兼容不过仍然可以执行。 default:false -->
        <setting name="useGeneratedKeys" value="true"/>
    </settings>
    <!--别名 配置别名后不区分大小写-->
    <typeAliases>
        <typeAlias alias="person" type="com.example.mybatis.entity.Person"/>
    </typeAliases>
    <!--映射器-->
    <mappers>
        <mapper resource="mappers/PersonMapper.xml"/>
    </mappers>
</configuration>

4、在entity中创建实体类Deptment和Person类

Person类

@Data
public class Person {

    private int id;

    private String PersonName;

    private int department_id;
}

Deptment类

@Data
public class Department {

    private int id;

    private String name;

    private int testId;

    private String data1;
    private String data2;
    private String data3;
}

5、创建Mapper，Mapper类和Mapper对应的xml,注册Mapper接口要增加注解@Mapper 如下：(Mapper接口 如果不加 @Mapper 则需要在启动类上增加 @MapperScan("mapper接口所在包名") ）

其中DeptMapper接口，采用注解实现

@Mapper
public interface DeptMapper {

    @Select("select * from department where id=#{id}")
    Department getDepById(int id);

    @Delete("delete from department where id=#{id}")
    int deleteDepById(int id);

    @Options(useGeneratedKeys = true,keyProperty = "id")
    @Insert("insert into department(name) values(#{name})")
    int insertDept(Department department);

    @Update("update department set name=#{name} where id=#{id}")
    int updateDept(Department department);
}

PersonMapper接口采用xml实现，

@Mapper
public interface PersonMapper {

     Person getPersonById(int id);

     String insertPerson(Person person);

}

PersonMapper.xml

<?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.mybatis.mapper.PersonMapper">

    <select id="getPersonById" parameterType="int" resultType="person">
         select * from person where id = #{id}
    </select>

    <insert id="insertPerson">
        insert into person(PersonName,department_id) values (#{PersonName},#{department_id})
    </insert>
    <update id="updatePerson">

    </update>
</mapper>

6、创建Controller 定义访问接口，如下：

PersonController

@RestController
public class PersonController {

    @Autowired
    PersonMapper personMapper;

    @GetMapping("/per/{id}")
    public Person getPersonById(@PathVariable int id){
        return personMapper.getPersonById(id);
    }
}

DepController

@RestController
public class DepController {

    @Autowired
    DeptMapper deptMapper;

    @GetMapping("/dept/{id}")
    public Department getDeptMapper(@PathVariable int id) {
        return deptMapper.getDepById(id);
    }

    @GetMapping("/dept")
    public Department insertDeptMapper( Department department){
        System.out.println("准备进行插入数据操作！");
        deptMapper.insertDept(department);
        return department;
    }
}

6、定义启动类，注意此类需要多增加一个注解@MapperScan("mapper类所在包名")，如下：（如果启动类增加@MapperSscan 那么 Mapper接口上则可不用加 @Mapper)

@MapperScan(value = "com.example.mybatis.mapper")
@SpringBootApplication
public class MybatisApplication {

    public static void main(String[] args) {

        SpringApplication.run(MybatisApplication.class, args);
        System.out.println("启动成功......");
    }

}

8、运行正常