扬州高邮网站建设焊工培训心得体会

一、新建一个spring boot项目

如何在idea中创建一个SpringBoot项目（超详细教学）_我是老伯的博客-CSDN博客

二、建立分层包

添加依赖

<dependency><groupId>com.baomidou</groupId><artifactId>mybatis-plus-boot-starter</artifactId><version>3.4.2</version>
</dependency>

1. config层 MybatisPlusConfig.java   

集成完毕分页插件之后，可去掉PageHelper 分页插件

@Configuration
public class MybatisPlusConfig {// 最新版@Bean  // <bean id=""/>public MybatisPlusInterceptor mybatisPlusInterceptor() {MybatisPlusInterceptor interceptor = new MybatisPlusInterceptor();interceptor.addInnerInterceptor(new PaginationInnerInterceptor(DbType.MYSQL));return interceptor;}
}

2. entity层 Student.java

@Data
public class Student {private Long id;private String name;private String number;}

3.mapper层 StudentMapper.java

public interface StudentMapper extends BaseMapper<Student> {
}

4.service层 Impl包下StudentServiceImpl.java

@Service
public class StudentServiceImpl extends ServiceImpl<StudentMapper, Student> implements StudentService {
}

StudentService.java

public interface StudentService extends IService<Student> {}

mybatis plus配置

application.yaml

spring:datasource:url: jdbc:mysql://localhost:3306/qcby_db?useUnicode=true&characterEncoding=utf-8&serverTimezone=CTTusername: rootpassword: 密码driver-class-name: com.mysql.cj.jdbc.Driver
# mybatis-plus配置
mybatis-plus:configuration:log-impl: org.apache.ibatis.logging.stdout.StdOutImpltypeAliasesPackage: com.qcby.zsgc.entitymapperLocations: classpath:mapper/*.xml#  全局配置id自增global-config:db-config:id-type: autopagehelper:helperDialect: mysqlreasonable: true # 修改默认值

5. controller层 Studentcontroller.java

@RestController
@RequestMapping("/student")
public class StudentController {@Autowiredprivate StudentService studentService;@RequestMapping("save")public void save(Student student){studentService.save(student);}@RequestMapping("update")public void update(Student student) {studentService.updateById(student);}@RequestMapping("saveOrUpdate")public void saveOrUpdate(Student student){studentService.saveOrUpdate(student);}@RequestMapping("removeById")public void removeById(Long id) {studentService.removeById(id);}@RequestMapping("list")public List<Student> list(Long id) {return studentService.list();}/*** 查询条件 =》name得模糊查询 和 number精确匹配  可选的* @param pageNo* @param pageSize* @return*/@RequestMapping("listPage")public Page<Student> listPage(Integer pageNo,Integer pageSize){Page<Student> page =new Page(pageNo,pageSize);return studentService.page(page);}
}

 添加模糊查询和精确查询

@RequestMapping("listPage")public Page<Student> listPage(Integer pageNo,Integer pageSize,Student student){//处理分页Page<Student> page =new Page(pageNo,pageSize);//帮助我们拼接whereQueryWrapper<Student> queryWrapper = new QueryWrapper();if(!StringUtils.isEmpty(student.getName())){queryWrapper.like("name",student.getName());}if (!StringUtils.isEmpty(student.getNumber())) {queryWrapper.eq("numner",student.getNumber());}//添加分页 和查询条件return studentService.page(page,queryWrapper);}