目录

• 一、SpringBoot整合MyBatis
• 二、Mybatis增删改查(使用注解方式)
• 三、Mybatis增删改查(XML配置方式)

一、SpringBoot整合MyBatis

跳转到目录

引入依赖

<dependencies><dependency><groupId>org.springframework.boot</groupId><artifactId>spring-boot-starter-jdbc</artifactId></dependency><dependency><groupId>org.springframework.boot</groupId><artifactId>spring-boot-starter-web</artifactId></dependency><dependency><groupId>org.mybatis.spring.boot</groupId><artifactId>mybatis-spring-boot-starter</artifactId><version>2.1.2</version></dependency><dependency><groupId>com.alibaba</groupId><artifactId>druid-spring-boot-starter</artifactId><version>1.1.20</version></dependency><dependency><groupId>mysql</groupId><artifactId>mysql-connector-java</artifactId><scope>runtime</scope></dependency><dependency><groupId>org.springframework.boot</groupId><artifactId>spring-boot-starter-test</artifactId><scope>test</scope><exclusions><exclusion><groupId>org.junit.vintage</groupId><artifactId>junit-vintage-engine</artifactId></exclusion></exclusions></dependency></dependencies>

依赖关系

项目构建

1、在resources下创建department.sql和employee.sql，项目启动时创建表(在数据库中自动生成)

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

2、实体类

public class Department {private Integer id;private String departmentName;  	// 省略 getter/setter 方法}

public class Employee {private Integer id;private String lastName;private Integer gender;private String email;private Integer dId;// 省略 getter/setter 方法}

3、配置文件

spring:  datasource:useame: rootpassword: 1111url: jdbc:mysql://localhost:3306/springboot_mybatisdriver-class-name: com.mysql.jdbc.Driverinitialization-mode: always# 数据源更改为druidtype: com.alibaba.druid.pool.DruidDataSourcedruid:  # 连接池配置  # 配置初始化大小、最小、最大  initial-size: 1  min-idle: 1  max-active: 20  # 配置获取连接等待超时的时间  max-wait: 3000  validation-query: SELECT 1 FROM DUAL  test-on-borrow: false  test-on-retu: false  test-while-idle: true  pool-prepared-statements: true  time-between-eviction-runs-millis: 60000  min-evictable-idle-time-millis: 300000  filters: stat,wall,slf4j  # 配置web监控,默认配置也和下面相同(除用户名密码，enabled默认false外)，其他可以不配  web-stat-filter:enabled: trueurl-patte: /*exclusions: "*.js,*.gif,*.jpg,*.png,*.css,*.ico,/druid/*"  stat-view-servlet:enabled: trueurl-patte: /druid/*login-useame: adminlogin-password: rootallow: 127.0.0.1schema:  - classpath:sql/department.sql  - classpath:sql/employee.sql

二、Mybatis增删改查(使用注解方式)

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• 创建mapper接口

/** * Description: * * @author zygui * @date 2020/4/17 16:10 */// 指定这是一个操作数据库的mapper@Mapper // 这里必须要添加这个Mapper注解; 也可以在主启动类上统一通过@MapperScan(value="con.zy.mapper")来扫描public interface DepartmentMapper {@Select("SELECT * FROM department WHERE id = #{id}")public Department getDeptById(@Param("id") Integer id);@Delete("DELETE FROM department WHERE id = #{id}")public int deleteDeptById(@Param("id") Integer id);@Options(useGeneratedKeys = true, keyProperty = "id")@Insert("INSERT INTO department(department_name) VALUES(#{departmentName})")public int insertDept(Department department);@Update("UPDATE department SET department_name = #{departmentName} WHERE id = #{id}")public int updateDept(Department department);}

• 创建Controller

@RestControllerpublic class DeptController {@Resourceprivate DepartmentMapper departmentMapper;@GetMapping("/dept/{id}")public Department getDepartment(@PathVariable("id") Integer id) {retu departmentMapper.getDeptById(id);}@GetMapping("/dept")public Department insertDept(Department department) {int count = departmentMapper.insertDept(department);if (count > 0) {System.out.println("插入数据成功");}retu department;}

• 访问：http://localhost:8080/dept?departmentName=gzy 添加一条数据

  访问：http://localhost:8080/dept/1获取数据

Mybatis配置

开启驼峰命名法

我们的实体类和表中的列名一致，一点问题也没有

我们把department表的departmentName列名改为department_name看看会发生什么

访问：http://localhost:8080/dept/1获取数据

[{“id”:1,“departmentName”:null}]

由于列表和属性名不一致，所以就没有封装进去，我们表中的列名和实体类属性名都是遵循驼峰命名规则的，可以开启mybatis的开启驼峰命名配置

# 开启驼峰映射mybatis:  configuration:map-underscore-to-camel-case: true

然后重启项目，重新插入数据，再查询就发现可以封装进去了

也可以通过向spring容器中注入org.mybatis.spring.boot.autoconfigure.ConfigurationCustomizer的方法设置mybatis参数

@org.springframework.context.annotation.Configurationpublic class MyBatisConfig {@Beanpublic ConfigurationCustomizer configurationCustomizer(){retu new ConfigurationCustomizer() {@Overridepublic void customize(Configuration configuration) {// 开启驼峰命名映射configuration.setMapUnderscoreToCamelCase(true);}};}}

Mapper扫描

使用@mapper注解的类可以被扫描到容器中，但是每个Mapper都要加上这个注解就是一个繁琐的工作，能不能直接扫描某个包下的所有Mapper接口呢，当然可以，在springboot启动类上加上@MapperScan

@MapperScan(“cn.clboy.springbootmybatis.mapper”)

三、Mybatis增删改查(XML配置方式)

跳转到目录

• 创建mybatis全局配置文件

<?xml version="1.0" encoding="UTF-8" ?><!DOCTYPE configurationPUBLIC "-//mybatis.org//DTD Config 3.0//EN""http://mybatis.org/dtd/mybatis-3-config.dtd"><configuration><!-- 开启数据库中列名和pojp的驼峰命名映射 --><settings><setting name="mapUnderscoreToCamelCase" value="true"/></settings></configuration>

• 创建EmployeeMapper接口

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

• 创建EmployeeMapper.xml映射文件

<?xml version="1.0" encoding="UTF-8" ?><!DOCTYPE mapperPUBLIC "-//mybatis.org//DTD Mapper 3.0//EN""http://mybatis.org/dtd/mybatis-3-mapper.dtd"><mapper namespace="com.zy.mapper.EmployeeMapper"><select id="getEmpById" resultType="com.zy.pojo.Employee">SELECT * FROM employee WHERE id = #{id};</select><insert id="insertEmp">INSERT INTO employee (lastName, email, gender, d_id) VALUSE (#{lastName}, #{email}, #{gender}, #{dId})</insert></mapper>

• 配置文件(application.yaml)中指定配置文件和映射文件的位置

# 加载mybati的全局配置文件mybatis:  config-location: classpath:mybatis/mybatis-config.xml  mapper-locations: classpath:mybatis/mapper/*.xml

• Controller

@RestControllerpublic class EmpController {	@Resourceprivate EmployeeMapper employeeMapper;@GetMapping("/emp/{id}")public Employee getEmp(@PathVariable("id") Integer id) {retu employeeMapper.getEmpById(id);}}

• 测试