Spring Boot框架 - 数据访问 - 整合Mybatis

Posted 2021-03-13 爱穿新衣服的姑凉

一、新建Spring Boot项目

     注意：创建的时候勾选Mybatis依赖，pom文件如下

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

二、配置文件application.properties中配置数据库信息

三、创建两个表（Employee，Department）

四、创建JavaBean 用来封装表的数据

五、使用mybatis对数据库进行操作

• 配置文件方式
  • 在resources目录下新建目录：

　　　　　　

• • 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>
    
    </configuration>

  • EmployeeMapper.xml 内容如下

     1 <?xml version="1.0" encoding="UTF-8" ?>
     2 <!DOCTYPE mapper
     3         PUBLIC "-//mybatis.org//DTD Mapper 3.0//EN"
     4         "http://mybatis.org/dtd/mybatis-3-mapper.dtd">
     5 
     6 <!--将EmployeeMapper的全类名（右键复制相对路径）复制出来，放在namespace里面-->
     7 <mapper namespace="com.demo.springboot.mapper.EmployeeMapper">
     8 
     9     <!--将接口的方法配置到映射文件中
    10     id="方法名"
    11     resultType="返回值类型Employee的全类名"-->
    12     <select id="getEmpById" resultType="com.demo.springboot.bean.Employee">
    13         select * from Employee where id=#{id};
    14     </select>
    15 </mapper>

  • 将EmployeeMapper接口的方法配置在映射文件EmployeeMapper.xml中 

  • 在application.properties 中添加配置

    #mybatis配置
    mybatis.config-location=classpath:mybatis/mybatis-config.xml
    mybatis.mapper-locations=classpath:mybatis/mapper/*.xml

  • 运行后测试（同下面的注解版 “***测试：新增一个Controller.DeptController”）　　　
• 注解版方式
  • 创建包：mapper
  • 在包下添加一个接口：DepartmentMapper

     1 /**
     2  * 指定这是一个操作数据库的mapper
     3  */
     4 @Mapper
     5 public interface DepartmentMapper {
     6 
     7     @Select("select * from Department where id=#{id}")
     8     public Department getDeptById(Integer id);
     9 
    10     @Delete("delete from Department where id=#{id}")
    11     public int deleteDeptById(Integer id);
    12 
    13     @Insert("insert into Department(departmentName) values=(#{departmentName})")
    14     public int insertDept(Department department);
    15 
    16     @Update("update Department set departmentName=#{departmentName} where id=#{id}")
    17     public int updateDept(Department department);
    18 }

  • ***测试：新增一个Controller.DeptController

     1 @RestController
     2 public class DeptController {
     3 
     4     @Autowired
     5     DepartmentMapper departmentMapper;
     6 
     7    //查询，带入浏览器中的参数id
     8     @GetMapping("dept/{id}")
     9     public Department getDepartment(@PathVariable("id") Integer id){
    10         return departmentMapper.getDeptById(id);
    11     }
    12 
    13    //插入
    14     @GetMapping("dept/add")
    15     public Department addDepartment(Department department){
    16         departmentMapper.insertDept(department);
    17         return department;
    18     }
    19 }

  • 测试结果：

    • 测试查询：在浏览器输入地址 http://localhost:8080/dept/1

    • 测试插入：http://localhost:8080/dept/add?departmentName=%E6%8A%80%E6%9C%AF%E9%83%A8&empNum=13 查看数据库，新增数据成功