SpringBoot学习笔记：整合mybatis

Posted 2022-11-23 听风者-better

本文介绍SpringBoot整合mybatis

一.创建一个SpringBoot项目

1. 引入相应的依赖

   <dependency>
       <groupId>org.mybatis.spring.boot</groupId>
       <artifactId>mybatis-spring-boot-starter</artifactId>
       <version>2.1.2</version>
   </dependency>
   <dependency>
       <groupId>mysql</groupId>
       <artifactId>mysql-connector-java</artifactId>
       <scope>runtime</scope>
   </dependency>
   

2. 创建测试表

   CREATE TABLE `user`  (
     `id` int(11) NOT NULL AUTO_INCREMENT,
     `name` varchar(255) CHARACTER SET utf8 COLLATE utf8_general_ci NULL DEFAULT NULL,
     `age` int(11) NULL DEFAULT NULL,
     PRIMARY KEY (`id`) USING BTREE
   ) ENGINE = InnoDB AUTO_INCREMENT = 2 CHARACTER SET = utf8 COLLATE = utf8_general_ci ROW_FORMAT = Dynamic;
   
   SET FOREIGN_KEY_CHECKS = 1;   
   

3. 配置jdbc配置

   spring.datasource.driver-class-name=com.mysql.cj.jdbc.Driver
   spring.datasource.url=jdbc:mysql://127.0.0.1:3306/test?useUnicode=true&characterEncoding=utf8&useSSL=false&serverTimezone=UTC
   spring.datasource.username=root
   spring.datasource.password=root
   

二.编写具体实现接口

1. 创建实体类

   public class User 
       private int id;
       private String name;
       private int age;
       //setter/getter省略
   

2. 创建接口

   @Mapper
   public interface UserMapper 
   
       public List<User> getAllUser();
   
       public int addUser(User user);
   
   

   @Mapper注解标记这个接口作为一个映射接口 也可以在启动类里添加@MapperScan(“对应mapper包名”)

   这样就可以不用每个接口都添加@Mapper注释了

3. 创建mapper文件

   在resources目录下添加mapper文件夹用于存放mapper文件

   application.properties里声明mapper文件存放的位置即可

   mybatis.mapper-locations=classpath:/mapper/*.xml
   

   mapper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.twy.mybatisdemo.mapper.UserMapper">
       <select id="getAllUser" resultType="com.twy.mybatisdemo.entity.User">
           select * from user
       </select>
   
       <insert id="addUser">
           insert into user (id,name,age) values (#id,#name,#age)
       </insert>
   </mapper>
   

三.编写测试类

@SpringBootTest
class MybatisApplicationTests 

    @Autowired
    private UserMapper userMapper;

    @Test
    public void test() 
        User user = new User();
        user.setName("唐万言");
        user.setAge(20);
        userMapper.addUser(user);
        List<User> list = userMapper.getAllUser();
        for (User u : list) 
            System.out.println(u);
        
    

输出结果：