前言：
网上关于这部分的资料有很多，但是都很零散，今天为了总结一下以前自己学习的，所以准备在这里写一篇完整的教程，希望对你们有用。

项目结构

开发环境

• 开工工具：IDEA
• 基础工具：Maven JDK8
• 技术：Spring+Mybatis
• 数据库：Mysql
• SpringBoot版本：2.1.1

创建工程

• 创建springboot工程
  
  
  工程这里就不细说了，贴一下pom文件内容吧。

<?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>2.2.2.RELEASE</version>
        <relativePath/> <!-- lookup parent from repository -->
    </parent>
    <groupId>com.asong.demo</groupId>
    <artifactId>demomybat</artifactId>
    <version>0.0.1-SNAPSHOT</version>
    <packaging>jar</packaging>
    <name>demomybat</name>
    <description>Demo project for Spring Boot</description>

    <properties>
        <java.version>1.8</java.version>
    </properties>

    <dependencies>
        <dependency>
            <groupId>org.mybatis.spring.boot</groupId>
            <artifactId>mybatis-spring-boot-starter</artifactId>
            <version>2.1.1</version>
        </dependency>
        <dependency>
            <groupId>org.springframework.boot</groupId>
            <artifactId>spring-boot-starter-web</artifactId>
        </dependency>
        <!--Mysql数据库驱动-->
        <dependency>
            <groupId>mysql</groupId>
            <artifactId>mysql-connector-java</artifactId>
            <version>8.0.15</version>
        </dependency>
        <dependency>
            <groupId>org.springframework.boot</groupId>
            <artifactId>spring-boot-starter-test</artifactId>
            <scope>test</scope>
            <exclusions>
                <exclusion>
                    <groupId>org.junit.vintage</groupId>
                    <artifactId>junit-vintage-engine</artifactId>
                </exclusion>
            </exclusions>
        </dependency>
    </dependencies>

    <build>
        <plugins>
            <plugin>
                <groupId>org.springframework.boot</groupId>
                <artifactId>spring-boot-maven-plugin</artifactId>
            </plugin>
        </plugins>
        <resources>
            <resource>
                <directory>src/main/java</directory>
                <includes>
                    <include>**/*.yml</include>
                    <include>**/*.properties</include>
                    <include>**/*.xml</include>
                </includes>
                <filtering>false</filtering>
            </resource>
            <resource>
                <directory>src/main/resources</directory>
                <includes>
                    <include>**/*.yml</include>
                    <include>**/*.properties</include>
                    <include>**/*.xml</include>
                </includes>
                <filtering>false</filtering>
            </resource>
        </resources>
    </build>
</project>

创建数据库表

因为为了测试，我们的用户表只创建4个字段如下：

CREATE TABLE `user` (
  `id` int(13) NOT NULL AUTO_INCREMENT COMMENT '主键',
  `name` varchar(33) DEFAULT NULL COMMENT '姓名',
  `age` int(3) DEFAULT NULL COMMENT '年龄',
  `money` double DEFAULT NULL COMMENT '账户余额',
  PRIMARY KEY (`id`)
) ENGINE=InnoDB AUTO_INCREMENT=5 DEFAULT CHARSET=utf8

配置application.yml文件

如下：

server:
  port: 8080

spring:
  datasource:
    url: jdbc:mysql://localhost:3306/demo?useUnicode=true&characterEncoding=utf-8&serverTimezone=Asia/Shanghai
    username: root
    password: root

这里需要注意的是，我们使用的mysql-connector-java 8+ ，JDBC 连接到mysql-connector-java 6+以上的需要指定时区 serverTimezone=GMT%2B8。另外我们之前使用配置 Mysql数据连接是一般是这样指定driver-class-name=com.mysql.jdbc.Driver,但是现在不可以必须为 否则控制台下面的异常：

Loading class `com.mysql.jdbc.Driver'. This is deprecated. The new driver class is `com.mysql.cj.jdbc.Driver'. The driver is automatically registered via the SPI and manual loading of the driver class is generally unnecessary.

代码实现

1. 创建用户类Bean

public class User {
    
    private int id;
    private String name;
    private int age;
    private double money;

    public User(){
    }

    public User(int id, String name, int age, double money) {
    
        this.id = id;
        this.name = name;
        this.age = age;
        this.money = money;
    }

    public int getId() {
    
        return id;
    }

    public String getName() {
    
        return name;
    }

    public int getAge() {
    
        return age;
    }

    public double getMoney() {
    
        return money;
    }

    public void setId(int id) {
    
        this.id = id;
    }

    public void setName(String name) {
    
        this.name = name;
    }

    public void setAge(int age) {
    
        this.age = age;
    }

    public void setMoney(double money) {
    
        this.money = money;
    }

    @Override
    public String toString() {
    
        return "User{" +
                "id=" + id +
                ", name='" + name + '\'' +
                ", age=" + age +
                ", money=" + money +
                '}';
    }
}

2.Dao层

@Mapper
public interface UserDao {
    
    /**
     * 通过名字查询用户信息
     */
    @Select("SELECT * FROM user WHERE name = #{name}")
    User findUserByName(@Param("name") String name);

    /**
     * 查询所有用户信息
     * @return
     */
    @Select("SELECT * FROM user")
    List<User> findAllUser();

    /**
     * 插入用户信息
     * @param name
     * @param age
     * @param money
     */
    @Insert("INSERT INTO user(name, age,money) VALUES(#{name}, #{age}, #{money})")
    void insertUser(@Param("name") String name,@Param("age") Integer age,@Param("money") Double money);

    /**
     * 根据 id 更新用户信息
     */
    @Update("UPDATE  user SET name = #{name},age = #{age},money= #{money} WHERE id = #{id}")
    void updateUser(@Param("name") String name, @Param("age") Integer age, @Param("money") Double money,
                    @Param("id") int id);

    /**
     * 根据 id 删除用户信息
     */
    @Delete("DELETE from user WHERE id = #{id}")
    void deleteUser(@Param("id") int id);
}

3. Service层

@Service
public class UserService {
    
    @Autowired
    private UserDao userDao;

    /**
     * 根据名字查找用户
     * @param name
     * @return
     */

    public User selectUserByName(String name)
    {
    
        return userDao.findUserByName(name);
    }

    /**
     * 插入两个用户
     */
    public void insertService(){
    
        userDao.insertUser("sunsong",22,4000.0);
        userDao.insertUser("zhang",20,4000.0);
    }

    /**
     * 查找所有用户
     * @return
     */
    public List<User> selectAllUser(){
    
        return userDao.findAllUser();
    }

    /**
     * 根据id删除用户
     * @param id
     */
    public void deleteService(int id)
    {
    
        userDao.deleteUser(id);
    }
    @Transactional
    public void changemoney(){
    
        userDao.updateUser("sunsong",21,2000.0,3);
        //模拟转账过程中可能遇到的意外情况
        int test = 1 / 0;
        userDao.updateUser("zhang",19,3000.0,4);
    }
}

4. Controller层

@Controller
@RequestMapping("/user")
public class UserController {
    

    @Autowired
    private UserService userService;

    @RequestMapping("/query")
    public User testQuery() {
    
        return userService.selectUserByName("sunsong");
    }

    @RequestMapping("/insert")
    public List<User> testInsert() {
    
        userService.insertService();
        return userService.selectAllUser();
    }


    @RequestMapping("/changemoney")
    public List<User> testchangemoney() {
    
        userService.changemoney();
        return userService.selectAllUser();
    }

    @RequestMapping("/delete")
    public String testDelete() {
    
        userService.deleteService(3);
        return "OK";
    }
}

运行程序

总结

这个项目完全是通过全注解方式进行开发，还可以通过XML方式的进行开发，等我发下一次整理发出来吧，总体实现还是很简单。