添加依赖dependencygroupIdcom.baomidou/groupIdartifactIdmybatis-plus-spring-boot3-starter/artifactIdversion3.5.17/version/dependency!--MySQL--dependencygroupIdmysql/groupIdartifactIdmysql-connector-java/artifactIdversion8.0.33/version/dependencydependencygroupIdorg.projectlombok/groupIdartifactIdlombok/artifactIdoptionaltrue/optional/dependency配置server:servlet:context-path:/api port:8080#DataSourceConfigspring:application:name:happy-pet-server datasource:driver-class-name:com.mysql.cj.jdbc.Driverurl:jdbc:mysql://localhost:3306/springbootdemo?useUnicodetruecharacterEncodingutf-8useSSLfalseserverTimezoneAsia/ShanghaiallowPublicKeyRetrievaltrueusername:root password:sql102326 data:redis:host:localhost port:6379password:database:0timeout:5000ms servlet:multipart:max-file-size:10MBmax-request-size:20MBmybatis-plus:mapper-locations:classpath:mapper/**/*.xml在Spring Boot启动类中添加MapperScan注解扫描Mapper文件夹SpringBootApplicationMapperScan(com.example.springboot.mapper)publicclassApplication{publicstaticvoidmain(String[]args){SpringApplication.run(Application.class,args);}}编码packagecom.example.springboot.entity;importcom.baomidou.mybatisplus.annotation.TableName;importlombok.Data;DataTableName(user)publicclassUser{privateLongid;privateStringname;privateIntegerage;privateStringemail;}packagecom.example.springboot.mapper;importcom.baomidou.mybatisplus.core.mapper.BaseMapper;importcom.example.springboot.entity.User;importorg.apache.ibatis.annotations.Mapper;MapperpublicinterfaceUserMapperextendsBaseMapperUser{}开始使用packagecom.example.springboot;importcom.baomidou.mybatisplus.core.toolkit.Assert;importcom.example.springboot.entity.User;importcom.example.springboot.mapper.UserMapper;importorg.junit.jupiter.api.Test;importorg.springframework.beans.factory.annotation.Autowired;importorg.springframework.boot.test.context.SpringBootTest;importjava.util.List;SpringBootTestclassApplicationTests{AutowiredprivateUserMapperuserMapper;TestvoidcontextLoads(){System.out.println((----- selectAll method test ------));ListUseruserListuserMapper.selectList(null);Assert.isTrue(5userList.size(),);userList.forEach(System.out::println);}}控制台输出User(id1,nameJone,age18,emailtest1baomidou.com)User(id2,nameJack,age20,emailtest2baomidou.com)User(id3,nameTom,age28,emailtest3baomidou.com)User(id4,nameSandy,age21,emailtest4baomidou.com)User(id5,nameBillie,age24,emailtest5baomidou.com)