导入依赖

pom.xml

<?xml version="1.0" encoding="UTF-8"?>
<project xmlns="http://maven.apache.org/POM/4.0.0" xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
         xsi:schemaLocation="http://maven.apache.org/POM/4.0.0 https://maven.apache.org/xsd/maven-4.0.0.xsd">
    <modelVersion>4.0.0</modelVersion>
    <parent>
        <groupId>org.springframework.boot</groupId>
        <artifactId>spring-boot-starter-parent</artifactId>
        <version>3.1.5</version>
        <relativePath/> <!-- lookup parent from repository -->
    </parent>
    <groupId>com.atguigu</groupId>
    <artifactId>boot3-05-ssm</artifactId>
    <version>0.0.1-SNAPSHOT</version>
    <name>boot3-05-ssm</name>
    <description>boot3-05-ssm</description>
    <properties>
        <java.version>17</java.version>
    </properties>
    <dependencies>
        <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>3.0.2</version>
        </dependency>

        <dependency>
            <groupId>org.springframework.boot</groupId>
            <artifactId>spring-boot-devtools</artifactId>
            <scope>runtime</scope>
            <optional>true</optional>
        </dependency>
        <dependency>
            <groupId>com.mysql</groupId>
            <artifactId>mysql-connector-j</artifactId>
            <scope>runtime</scope>
        </dependency>
        <dependency>
            <groupId>org.projectlombok</groupId>
            <artifactId>lombok</artifactId>
            <optional>true</optional>
        </dependency>
        <dependency>
            <groupId>org.springframework.boot</groupId>
            <artifactId>spring-boot-starter-test</artifactId>
            <scope>test</scope>
        </dependency>
        <dependency>
            <groupId>org.mybatis.spring.boot</groupId>
            <artifactId>mybatis-spring-boot-starter-test</artifactId>
            <version>3.0.2</version>
            <scope>test</scope>
        </dependency>
    </dependencies>

    <build>
        <plugins>
            <plugin>
                <groupId>org.springframework.boot</groupId>
                <artifactId>spring-boot-maven-plugin</artifactId>
                <configuration>
                    <excludes>
                        <exclude>
                            <groupId>org.projectlombok</groupId>
                            <artifactId>lombok</artifactId>
                        </exclude>
                    </excludes>
                </configuration>
            </plugin>
        </plugins>
    </build>

</project>

修改配置文件

application.yml

spring:
  # 配置数据源
  datasource:
    url: jdbc:mysql://localhost:3306/test
    username: root
    password: 123456
    driver-class-name: com.mysql.cj.jdbc.Driver
    type: com.zaxxer.hikari.HikariDataSource

# 配置MyBatis
mybatis:
  mapper-locations: classpath:/mapper/*.xml
  configuration:
    map-underscore-to-camel-case: true  #开启驼峰命名

Mapper及配置文件

UserMapper.java

package com.atguigu.boot3.ssm.mapper;

import com.atguigu.boot3.ssm.bean.TUser;
import org.apache.ibatis.annotations.Param;

public interface UserMapper {

    TUser getUserById(@Param("id") Long id);
}

UserMapper.xml

可以使用MyBatisX插件生成该文件

<?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.atguigu.boot3.ssm.mapper.UserMapper">
    <select id="getUserById" resultType="com.atguigu.boot3.ssm.bean.TUser">
        select * from t_user where id=#{id}
    </select>
</mapper>

编写Controller及启动类

UserController.java

package com.atguigu.boot3.ssm.controller;

import com.atguigu.boot3.ssm.bean.TUser;
import com.atguigu.boot3.ssm.mapper.UserMapper;
import org.springframework.beans.factory.annotation.Autowired;
import org.springframework.web.bind.annotation.GetMapping;
import org.springframework.web.bind.annotation.PathVariable;
import org.springframework.web.bind.annotation.RestController;

@RestController
public class UserController {

    @Autowired
    UserMapper userMapper;

    @GetMapping("/user/{id}")
    public TUser getUser(@PathVariable("id") Long id){
        TUser user = userMapper.getUserById(id);
        return user;
    }
}

Boot305SsmApplication.java 启动类

这里添加了Mapper的包扫描@MapperScan

package com.atguigu.boot3.ssm;

import org.mybatis.spring.annotation.MapperScan;
import org.springframework.boot.SpringApplication;
import org.springframework.boot.autoconfigure.SpringBootApplication;

@MapperScan(basePackages = "com.atguigu.boot3.ssm.mapper")
@SpringBootApplication
public class Boot305SsmApplication {

    public static void main(String[] args) {
        SpringApplication.run(Boot305SsmApplication.class, args);
    }

}

数据库

初始化的数据

CREATE TABLE `t_user`
(
    `id`         BIGINT(20)   NOT NULL AUTO_INCREMENT COMMENT '编号',
    `login_name` VARCHAR(200) NULL DEFAULT NULL COMMENT '用户名称' COLLATE 'utf8_general_ci',
    `nick_name`  VARCHAR(200) NULL DEFAULT NULL COMMENT '用户昵称' COLLATE 'utf8_general_ci',
    `passwd`     VARCHAR(200) NULL DEFAULT NULL COMMENT '用户密码' COLLATE 'utf8_general_ci',
    PRIMARY KEY (`id`)
);
insert into t_user(login_name, nick_name, passwd) VALUES ('zhangsan','张三','123456');

参考：