Spring Boot 整合 MyBatis

<?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>2.6.6</version>
        <relativePath/> <!-- lookup parent from repository -->
    </parent>
    <artifactId>springboot_day3</artifactId>
    <version>0.0.1-SNAPSHOT</version>
    <dependencies>
        <dependency>
            <groupId>org.springframework.boot</groupId>
            <artifactId>spring-boot-starter-web</artifactId>
        </dependency>
        <dependency>
            <groupId>org.projectlombok</groupId>
            <artifactId>lombok</artifactId>
            <optional>true</optional>
        </dependency>
        <!--mysql-->
        <dependency>
            <groupId>mysql</groupId>
            <artifactId>mysql-connector-java</artifactId>
            <version>8.0.15</version>
        </dependency>
        <!--mybatis-->
        <dependency>
            <groupId>org.mybatis.spring.boot</groupId>
            <artifactId>mybatis-spring-boot-starter</artifactId>
            <version>2.2.0</version>
        </dependency>
        <dependency>
            <groupId>org.springframework.boot</groupId>
            <artifactId>spring-boot-starter-test</artifactId>
            <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>

CREATE TABLE USER(
  id INT PRIMARY KEY AUTO_INCREMENT,
  NAME VARCHAR (30) DEFAULT '该用户什么都没写',
  phone VARCHAR (20) UNIQUE,
  pwd INT NOT NULL
) ;

@Data
public class User {
    private Long id;
    private String name;
    private String phone;
    private String pwd;
}

package com.liu.dao;
import com.liu.entity.User;
import java.util.List;
public interface UserDAO {
    List<User> findAll();
    User findById(Long id);
    void save(User user);
    void update(User user);
    void deleteById(Long id);
}

<?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.liu.dao.UserDAO">
    <select resultType="com.liu.entity.User" id="findAll">
        select * from user;
    </select>
    <select id="findById" parameterType="java.lang.Long" resultType="com.liu.entity.User">
        select *
        from user where id = #{id};
    </select>
    <insert id="save" parameterType="com.liu.entity.User">
        insert into user (name, phone, pwd)
        values (#{name},#{phone},#{pwd});
    </insert>
    <update id="update" parameterType="java.lang.Long">
        update user
        set name = #{name},phone=#{phone},pwd=#{pwd}
        where id = #{id};
    </update>
    <delete id="deleteById" parameterType="java.lang.Long">
        delete
        from user
        where id = #{id};
    </delete>
</mapper>

@RestController
@RequestMapping("user")
public class UserController {
    @Autowired
    private UserDAO userDAO;
    @GetMapping("/findAll")
    public List<User> findAll() {
        return userDAO.findAll();
    }
    @GetMapping("/findById/{id}")
    public User findById(@PathVariable("id") long id) {
        return userDAO.findById(id);
    }
    /**
     * @param user
     * @RequestBody 这个注解把 json 格式的请求封装成 java 对象
     * @ResponseBody 这个注解把 java 对象转换成 json 格式返回给 client
     */
    @PostMapping("/save")
    public void save(@RequestBody User user) {
        userDAO.save(user);
    }
    @PostMapping("/update")
    public void update(@RequestBody User user) {
        userDAO.update(user);
    }
    @DeleteMapping("/deleteById/{id}")
    public void deleteById(@PathVariable("id") long id) {
        userDAO.deleteById(id);
    }

spring:
  datasource:
    url: jdbc:mysql://localhost:3306/db08?useUnicode=true&characterEncoding=UTF-8
    username: root
    password: 8485
    driver-class-name: com.mysql.cj.jdbc.Driver
mybatis:
  mapper-locations: classpath:/mapping/*.xml
  type-aliases-package: com.liu.entity
1

package com.liu;
import org.mybatis.spring.annotation.MapperScan;
import org.springframework.boot.SpringApplication;
import org.springframework.boot.autoconfigure.SpringBootApplication;
@SpringBootApplication
@MapperScan("com.liu.dao")
public class SpringbootDay3Application {
    public static void main(String[] args) {
        SpringApplication.run(SpringbootDay3Application.class, args);
    }