Mybatis Hello World

基于Spring Boot框架实现一个Mybatis的Hello World实例

关于spring boot的相关知识，这里不在赘述

首先引入Maven依赖，这里同时引入了mybatis的starter和mysql的驱动包

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

数据库以及相关表已经建立好了，建表语句如下：

CREATE TABLE `learn`.`Untitled`  (
  `id` int NOT NULL AUTO_INCREMENT COMMENT '??',
  `name` varchar(50) CHARACTER SET utf8mb4 COLLATE utf8mb4_0900_ai_ci NOT NULL COMMENT '???',
  `phone` varchar(11) CHARACTER SET utf8mb4 COLLATE utf8mb4_0900_ai_ci NOT NULL COMMENT '???',
  `email` varchar(100) CHARACTER SET utf8mb4 COLLATE utf8mb4_0900_ai_ci NULL DEFAULT NULL COMMENT '??',
  `profession` varchar(11) CHARACTER SET utf8mb4 COLLATE utf8mb4_0900_ai_ci NULL DEFAULT NULL COMMENT '??',
  `age` tinyint UNSIGNED NULL DEFAULT NULL COMMENT '??',
  `gender` char(1) CHARACTER SET utf8mb4 COLLATE utf8mb4_0900_ai_ci NULL DEFAULT NULL COMMENT '?? , 1: ?, 2: ?',
  `status` char(1) CHARACTER SET utf8mb4 COLLATE utf8mb4_0900_ai_ci NULL DEFAULT NULL COMMENT '??',
  `createtime` datetime NULL DEFAULT NULL COMMENT '????',
  PRIMARY KEY (`id`) USING BTREE
) ENGINE = InnoDB AUTO_INCREMENT = 25 CHARACTER SET = utf8mb4 COLLATE = utf8mb4_0900_ai_ci COMMENT = '?????' ROW_FORMAT = Dynamic;

配置数据源

spring:
  datasource:
    url: jdbc:mysql://localhost:3306/learn
    driver-class-name: com.mysql.cj.jdbc.Driver
    username: root
    password: root

配置映射文件路径

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

编写映射文件

<?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.xul.mybatis.mapper.UserMapper">
    <select id="selectUser" resultType="com.xul.mybatis.model.UserModel">
        select * from tb_user where id = #{id}
    </select>
</mapper>

编写mapper接口

@Mapper
public interface UserMapper {
    UserModel selectUser(int id);
}

启动后直接调用接口，就可以达到返回值了