driver=com.mysql.cj.jdbc.Driver
url=jdbc:mysql://localhost:3306/wmmbooks?useSSL=true&useUnicode=true&characterEncoding=UTF-8&serverTimezone=UTC&allowPublicKeyRetrieval=true
user=root
password=123456

package com.hxl.pojo;

import lombok.AllArgsConstructor;
import lombok.Data;
import lombok.NoArgsConstructor;

@Data
@AllArgsConstructor
@NoArgsConstructor
public class Books {
    private int bookID;
    private String bookName;
    private int bookCounts;
    private String detail;
}

<dependency>
    <groupId>org.projectlombok</groupId>
    <artifactId>lombok</artifactId>
    <version>1.18.20</version>
</dependency>

package com.hxl.dao;

import com.hxl.pojo.Books;
import org.apache.ibatis.annotations.Param;

import java.util.List;

public interface BookMapper {

    //增加
    int addBook(Books books);
    //删除
    int deleteBookById(@Param("bookId")int id);
    //更新
    int updateBook(Books books);
    //查询一本书
    Books queryBookById(int id);
    //查询全部的书
    List<Books> queryAllBook();
}

<?xml version="1.0" encoding="UTF-8" ?>
<!DOCTYPE mapper
        PUBLIC "-//mybatis.org//DTD Config 3.0//EN"
        "http://mybatis.org/dtd/mybatis-3-mapper.dtd">
<mapper namespace="com.hxl.dao.BookMapper">
    <insert id="addBook" parameterType="Books">
        insert into wmmbooks.books (bookName,bookCounts,detail)
         values (#{bookName},#{bookCounts},#{detail})
    </insert>

    <!--这里写int是Integer,写_int才是int。但是java里可以转换，自动拆箱和装箱-->
    <!--这里写bookId是因为在接口中使用了@Param这个注解，否则需要写id-->
    <delete id="deleteBookById" parameterType="int">
        delete from wmmbooks.books where bookID = #{bookId}
    </delete>

    <update id="updateBook" parameterType="Books">
        update wmmbooks.books
        set bookName = #{bookName}, bookCounts=#{bookCounts},detail=#{detail}
        where bookID = #{bookID}
    </update>

    <select id="queryBookById" parameterType="Books">
        select * from wmmbooks.books where bookID = #{bookID}
    </select>

    <select id="queryAllBook" parameterType="Books">
        select * from wmmbooks.books
    </select>
</mapper>

<mappers>
    <mapper class="com.hxl.dao.BookMapper"/>
</mappers>

package com.hxl.service;

import com.hxl.pojo.Books;

import java.util.List;

public interface BookService {
    //增加
    int addBook(Books books);
    //删除
    int deleteBookById(int id);
    //更新
    int updateBook(Books books);
    //查询一本书
    Books queryBookById(int id);
    //查询全部的书
    List<Books> queryAllBook();
}