狂神说SpringBoot09：整合MyBatis

女爷i 2021-09-24 09:46 407阅读 0赞

> 狂神说SpringBoot系列连载课程，通俗易懂，基于SpringBoot2.2.5版本，欢迎各位狂粉转发关注学习。未经作者授权，禁止转载

![format_png][]

整合MyBatis

官方文档：http://mybatis.org/spring-boot-starter/mybatis-spring-boot-autoconfigure/

Maven仓库地址：https://mvnrepository.com/artifact/org.mybatis.spring.boot/mybatis-spring-boot-starter/2.1.1

![format_png 1][]

## 整合测试 ##

1、导入 MyBatis 所需要的依赖

<dependency>
        <groupId>org.mybatis.spring.boot</groupId>
        <artifactId>mybatis-spring-boot-starter</artifactId>
        <version>2.1.1</version>
    </dependency>

2、配置数据库连接信息（不变）

spring:
      datasource:
        username: root
        password: 123456
        #?serverTimezone=UTC解决时区的报错
        url: jdbc:mysql://localhost:3306/springboot?serverTimezone=UTC&useUnicode=true&characterEncoding=utf-8
        driver-class-name: com.mysql.cj.jdbc.Driver
        type: com.alibaba.druid.pool.DruidDataSource
    
    
        #Spring Boot 默认是不注入这些属性值的，需要自己绑定
        #druid 数据源专有配置
        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，stat:监控统计、log4j：日志记录、wall：防御sql注入
        #如果允许时报错  java.lang.ClassNotFoundException: org.apache.log4j.Priority
        #则导入 log4j 依赖即可，Maven 地址：https://mvnrepository.com/artifact/log4j/log4j
        filters: stat,wall,log4j
        maxPoolPreparedStatementPerConnectionSize: 20
        useGlobalDataSourceStat: true
        connectionProperties: druid.stat.mergeSql=true;druid.stat.slowSqlMillis=500

**3、测试数据库是否连接成功！**

**4、创建实体类，导入 Lombok！**

Department.java

package com.kuang.pojo;
    
    
    import lombok.AllArgsConstructor;
    import lombok.Data;
    import lombok.NoArgsConstructor;
    
    
    @Data
    @NoArgsConstructor
    @AllArgsConstructor
    public class Department {
    
    
        private Integer id;
        private String departmentName;
    
    
    }

**5、创建mapper目录以及对应的 Mapper 接口**

DepartmentMapper.java

//@Mapper : 表示本类是一个 MyBatis 的 Mapper
    @Mapper
    @Repository
    public interface DepartmentMapper {
    
    
        // 获取所有部门信息
        List<Department> getDepartments();
    
    
        // 通过id获得部门
        Department getDepartment(Integer id);
    
    
    }

**6、对应的Mapper映射文件**

DepartmentMapper.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.kuang.mapper.DepartmentMapper">
    
    
        <select id="getDepartments" resultType="Department">
           select * from department;
        </select>
    
    
        <select id="getDepartment" resultType="Department" parameterType="int">
           select * from department where id = #{id};
        </select>
    
    
    </mapper>

**7、maven配置资源过滤问题**

**8、编写部门的 DepartmentController 进行测试！**

@RestController
    public class DepartmentController {
        
        @Autowired
        DepartmentMapper departmentMapper;
        
        // 查询全部部门
        @GetMapping("/getDepartments")
        public List<Department> getDepartments(){
            return departmentMapper.getDepartments();
        }
    
    
        // 查询全部部门
        @GetMapping("/getDepartment/{id}")
        public Department getDepartment(@PathVariable("id") Integer id){
            return departmentMapper.getDepartment(id);
        }
        
    }

**启动项目访问进行测试！**

## 我们增加一个员工类再测试下，为之后做准备 ##

1、新建一个pojo类 Employee ；

@Data
    @AllArgsConstructor
    @NoArgsConstructor
    public class Employee {
    
    
        private Integer id;
        private String lastName;
        private String email;
        //1 male, 0 female
        private Integer gender;
        private Integer department;
        private Date birth;
    
    
        private Department eDepartment; // 冗余设计
    
    
    }

2、新建一个 EmployeeMapper 接口

//@Mapper : 表示本类是一个 MyBatis 的 Mapper
    @Mapper
    @Repository
    public interface EmployeeMapper {
    
    
        // 获取所有员工信息
        List<Employee> getEmployees();
    
    
        // 新增一个员工
        int save(Employee employee);
    
    
        // 通过id获得员工信息
        Employee get(Integer id);
    
    
        // 通过id删除员工
        int delete(Integer id);
    
    
    }

3、编写 EmployeeMapper.xml 配置文件

<?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">
    
    
    <mapper namespace="com.kuang.mapper.EmployeeMapper">
    
    
        <resultMap id="EmployeeMap" type="Employee">
            <id property="id" column="eid"/>
            <result property="lastName" column="last_name"/>
            <result property="email" column="email"/>
            <result property="gender" column="gender"/>
            <result property="birth" column="birth"/>
            <association property="eDepartment"  javaType="Department">
                <id property="id" column="did"/>
                <result property="departmentName" column="dname"/>
            </association>
        </resultMap>
    
    
        <select id="getEmployees" resultMap="EmployeeMap">
            select e.id as eid,last_name,email,gender,birth,d.id as did,d.department_name as dname
            from department d,employee e
            where d.id = e.department
        </select>
    
    
        <insert id="save" parameterType="Employee">
            insert into employee (last_name,email,gender,department,birth)
            values (#{lastName},#{email},#{gender},#{department},#{birth});
        </insert>
    
    
        <select id="get" resultType="Employee">
            select * from employee where id = #{id}
        </select>
    
    
        <delete id="delete" parameterType="int">
            delete from employee where id = #{id}
        </delete>
    
    
    </mapper>

4、编写EmployeeController类进行测试

@RestController
    public class EmployeeController {
    
    
        @Autowired
        EmployeeMapper employeeMapper;
    
    
        // 获取所有员工信息
        @GetMapping("/getEmployees")
        public List<Employee> getEmployees(){
            return employeeMapper.getEmployees();
        }
    
    
        @GetMapping("/save")
        public int save(){
            Employee employee = new Employee();
            employee.setLastName("kuangshen");
            employee.setEmail("qinjiang@qq.com");
            employee.setGender(1);
            employee.setDepartment(101);
            employee.setBirth(new Date());
            return employeeMapper.save(employee);
        }
    
    
        // 通过id获得员工信息
        @GetMapping("/get/{id}")
        public Employee get(@PathVariable("id") Integer id){
            return employeeMapper.get(id);
        }
    
    
        // 通过id删除员工
        @GetMapping("/delete/{id}")
        public int delete(@PathVariable("id") Integer id){
            return employeeMapper.delete(id);
        }
    
    
    }

测试结果完成，搞定收工！

![format_png 2][]

![format_png 3][]

[format_png]: /images/20210923/dcc9a4d7a77244269bb1d8c483291894.png
[format_png 1]: /images/20210923/71116b9f935c4627b38b05c6686d414a.png
[format_png 2]: /images/20210923/4250e6bf311e4aa3bfcc383c5f53fbf1.png
[format_png 3]: /images/20210923/34913fc39a03432b8549c183b292ed94.png