SpringBoot源码学习之路（十四、SpringBoot整合Mybatis （注解版和配置文件版））

╰+攻爆jí腚メ 2022-05-19 11:09 230阅读 0赞

## 整合MyBatis ##

#### 一、前置内容 ####

**Tip:创建project时注意要勾选：JDBC和Mybatis**  
![这里写图片描述][70]

**步骤**：  
**1.引入依赖：**

<dependency>
                <groupId>org.mybatis.spring.boot</groupId>
                <artifactId>mybatis-spring-boot-starter</artifactId>
                <version>1.3.1</version>
            </dependency>

![这里写图片描述][70 1]

**2、配置数据源相关属性（Druid依赖也需要引入）**

spring:
      datasource:
    # 数据源基本配置
        username: root
        password: 123456
        driver-class-name: com.mysql.jdbc.Driver
        url: jdbc:mysql://127.0.0.1:3306/mybatis
        type: com.alibaba.druid.pool.DruidDataSource
    # 数据源其他配置
        initialSize: 5
        minIdle: 5
        maxActive: 20
        maxWait: 60000
        timeBetweenEvictionRunsMillis: 60000
        minEvictableIdleTimeMillis: 300000
        validationQuery: SELECT 1 FROM DUAL
        testWhileIdle: true
        testOnBorrow: false
        testOnReturn: false
        poolPreparedStatements: true
    # 配置监控统计拦截的filters，去掉后监控界面sql无法统计，'wall'用于防火墙
        filters: stat,wall,log4j
        maxPoolPreparedStatementPerConnectionSize: 20
        useGlobalDataSourceStat: true
        connectionProperties: druid.stat.mergeSql=true;druid.stat.slowSqlMillis=500

**3、给数据库建表**  
`department.sql`:

SET FOREIGN_KEY_CHECKS=0;
    
    -- ----------------------------
    -- Table structure for department
    -- ----------------------------
    DROP TABLE IF EXISTS `department`;
    CREATE TABLE `department` ( `id` int(11) NOT NULL AUTO_INCREMENT, `departmentName` varchar(255) DEFAULT NULL, PRIMARY KEY (`id`) ) ENGINE=InnoDB AUTO_INCREMENT=1 DEFAULT CHARSET=utf8;

`employee.sql`:

SET FOREIGN_KEY_CHECKS=0;
    
    -- ----------------------------
    -- Table structure for employee
    -- ----------------------------
    DROP TABLE IF EXISTS `employee`;
    CREATE TABLE `employee` ( `id` int(11) NOT NULL AUTO_INCREMENT, `lastName` varchar(255) DEFAULT NULL, `email` varchar(255) DEFAULT NULL, `gender` int(2) DEFAULT NULL, `d_id` int(11) DEFAULT NULL, PRIMARY KEY (`id`) ) ENGINE=InnoDB AUTO_INCREMENT=1 DEFAULT CHARSET=utf8;

`application.yml`(启动时自动创建表):

schema:
          - classpath:sql/department.sql       - classpath:sql/employee.sql

**4、创建JavaBean**  
`Department.java`:

public class Department { 
    
        private Integer id;
        private String departmentName;
    }

`Employee.java`:

public class Employee { 
    
        private Integer id;
        private String lastName;
        private Integer gender;
        private String email;
        private Integer dId;
        }

--------------------

#### 二、整合注解版Mybatis（不需要任何的mybatis配置就可以直接使用了） ####

**1、Mapper**

@Mapper
    public interface DepartmentMapper { 
    
        @Select("select * from department where id=#{id}")
        public Department getDeptById(Integer id);
    
        @Delete("delete from department where id=#{id}")
        public int deleteDeptById(Integer id);
    
        @Options(useGeneratedKeys = true,keyProperty = "id")//告诉注解版的mybatis【department】对象中的id为自增主键
        @Insert("insert into department(departmentName) values(#{departmentName})")
        public int insertDept(Department department);
    
        @Update("update department set departmentName=#{departmentName} where id=#{id}")
        public int updateDept(Department department);
    }

**2、Controller**

@RestController
    public class DeptController { 
    
        @Autowired
        DepartmentMapper departmentMapper;
    
        @Autowired
        EmployeeMapper employeeMapper;
    
    
        @GetMapping("/dept/{id}")
        public Department getDepartment(@PathVariable("id") Integer id){
            return departmentMapper.getDeptById(id);
        }
    
        @GetMapping("/dept")
        public Department insertDept(Department department){
            departmentMapper.insertDept(department);
            return department;
        }
    
    }

**3、自定义MyBatis的配置规则，增加自定义mybatis配置，只需要给容器中添加一个`ConfigurationCustomizer`；如：**

@org.springframework.context.annotation.Configuration
    public class MyBatisConfig { 
    
        @Bean
        public ConfigurationCustomizer configurationCustomizer(){
            return new ConfigurationCustomizer(){
                @Override
                public void customize(Configuration configuration) {
                    //可以将表字段的下划线自动转成驼峰命名的方式和对象属性映射
                    configuration.setMapUnderscoreToCamelCase(true);
                }
            };
        }
    }

**4、使用MapperScan批量扫描所有的Mapper接口；（这样mapper包下的mapper接口就不需要加注解`@Mapper`也能被扫描）**

@MapperScan(value = "com.wangcw.springboot.mapper")
    @SpringBootApplication
    public class SpringBoot06DataMybatisApplication { 
    
        public static void main(String[] args) {
            SpringApplication.run(SpringBoot06DataMybatisApplication.class, args);
        }
    }

完成！

--------------------

#### 三、整合配置文件版的Mybatis ####

**1、Mapper**

//@Mapper或者@MapperScan将接口扫描装配到容器中
    public interface EmployeeMapper { 
    
        public Employee getEmpById(Integer id);
    
        public void insertEmp(Employee employee);
    }

**2、Mapper.xml**

<mapper namespace="com.springboot.mapper.EmployeeMapper">
        <select id="getEmpById" resultType="com.atguigu.springboot.bean.Employee">
            SELECT * FROM employee WHERE id=#{id}
        </select>
    
        <insert id="insertEmp">
            INSERT INTO employee(lastName,email,gender,d_id) VALUES (#{lastName},#{email},#{gender},#{dId})
        </insert>
    </mapper>

**3、Controller**

@Autowired
       private EmployeeMapper employeeMapper;
    
      @GetMapping("/emp/{id}")
        public Employee getEmp(@PathVariable("id") Integer id){
           return employeeMapper.getEmpById(id);
        }

**4、mybatis-config.xml**

<?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>
    
        <settings>
            <setting name="mapUnderscoreToCamelCase" value="true"/>
        </settings>
    </configuration>

**5、application.yml**

mybatis:
      # 指定全局配置文件位置
      config-location: classpath:mybatis/mybatis-config.xml
      # 指定sql映射文件位置
      mapper-locations: classpath:mybatis/mapper/*.xml

完成！  
更多使用参照：

[http://www.mybatis.org/spring-boot-starter/mybatis-spring-boot-autoconfigure/][http_www.mybatis.org_spring-boot-starter_mybatis-spring-boot-autoconfigure]

[70]: /images/20220519/d5152cf839f347bd9ae37db6c91a5bda.png
[70 1]: /images/20220519/3073f04cf5f3429ba1825c413b323521.png
[http_www.mybatis.org_spring-boot-starter_mybatis-spring-boot-autoconfigure]: http://www.mybatis.org/spring-boot-starter/mybatis-spring-boot-autoconfigure/