测试类

package com.example.demo07.dao;

import com.example.demo07.dto.Book;
import org.junit.jupiter.api.Test;
import org.springframework.beans.factory.annotation.Autowired;
import org.springframework.boot.test.context.SpringBootTest;

@SpringBootTest
public class BookDaoTestCase {

    @Autowired
    private BookDao bookDao;


    @Test
    public void testSave(){
        Book book = new Book();
        book.setName("葡萄牙的高山");
        book.setType("文学");
        book.setDescription("苦难");

        //insert方法，继承自BaseMapper
        int count = bookDao.insert(book);

        System.out.println(count);
    }

}

testSave运行报错

org.mybatis.spring.MyBatisSystemException: nested exception is org.apache.ibatis.reflection.ReflectionException: Could not set property 'id' of 'class com.example.demo07.dto.Book' with value '1638870899446804481' Cause: java.lang.IllegalArgumentException: argument type mismatch

我在book表中 id字段设置为自增，而MyBatisPlus默认使用 雪花算法

在application.yml配置文件中配置

mybatis-plus:
  global-config:
    db-config:
      #默认使用的是 assign_id,设置为auto,主键id自增
      id-type: auto 

再次测试：

结果：

1

测试前book表

测试后book表

BookDao

package com.example.demo07.dao;

import com.baomidou.mybatisplus.core.mapper.BaseMapper;
import com.example.demo07.dto.Book;
import org.apache.ibatis.annotations.Mapper;
import org.apache.ibatis.annotations.Select;

@Mapper
public interface BookDao extends BaseMapper<Book> {

}

dto

package com.example.demo07.dto;

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

//lombok注解 需要依赖
@Data
@AllArgsConstructor
@NoArgsConstructor
public class Book {
    private Integer id;
    private String type;
    private String name;
    private String description;

}

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>2.7.9</version>
        <relativePath/> <!-- lookup parent from repository -->
    </parent>
    <groupId>com.example</groupId>
    <artifactId>demo07</artifactId>
    <version>0.0.1-SNAPSHOT</version>
    <name>demo07</name>
    <description>Demo project for Spring Boot</description>
    <properties>
        <java.version>1.8</java.version>
    </properties>
    <dependencies>
        <dependency>
            <groupId>org.springframework.boot</groupId>
            <artifactId>spring-boot-starter-web</artifactId>
        </dependency>

        <dependency>
            <groupId>org.springframework.boot</groupId>
            <artifactId>spring-boot-devtools</artifactId>
            <scope>runtime</scope>
            <optional>true</optional>
        </dependency>
        <dependency>
            <groupId>com.baomidou</groupId>
            <artifactId>mybatis-plus-boot-starter</artifactId>
            <version>3.4.3</version>
        </dependency>
        <dependency>
            <groupId>com.alibaba</groupId>
            <artifactId>druid-spring-boot-starter</artifactId>
            <version>1.2.6</version>
        </dependency>

        <dependency>
            <groupId>com.mysql</groupId>
            <artifactId>mysql-connector-j</artifactId>
            <scope>runtime</scope>
        </dependency>
        <dependency>
            <groupId>org.springframework.boot</groupId>
            <artifactId>spring-boot-configuration-processor</artifactId>
            <optional>true</optional>
        </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>
    </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>

application.yml

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

mybatis-plus:
  global-config:
    db-config:
      #默认使用的是 assign_id,设置为auto,主键id自增
      id-type: auto