mybatis plus配置以及controller层增删改查、分页

叁歲伎倆 2023-10-06 22:05 21阅读 0赞

### 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][idea_SpringBoot_-CSDN]

### 二、建立分层包 ###

![watermark_type_d3F5LXplbmhlaQ_shadow_50_text_Q1NETiBA5Y-r5oiR6ICB5Lyv_size_13_color_FFFFFF_t_70_g_se_x_16][]

### 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=CTT
        username: root
        password: 密码
        driver-class-name: com.mysql.cj.jdbc.Driver
    # mybatis-plus配置
    mybatis-plus:
      configuration:
        log-impl: org.apache.ibatis.logging.stdout.StdOutImpl
      typeAliasesPackage: com.qcby.zsgc.entity
      mapperLocations: classpath:mapper/*.xml
      #  全局配置id自增
      global-config:
        db-config:
          id-type: auto
    
    pagehelper:
      helperDialect: mysql
      reasonable: true # 修改默认值

#### 5. controller层 Studentcontroller.java ####

@RestController
    @RequestMapping("/student")
    public class StudentController {
        @Autowired
        private 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);
        }
    }

![watermark_type_d3F5LXplbmhlaQ_shadow_50_text_Q1NETiBA5Y-r5oiR6ICB5Lyv_size_20_color_FFFFFF_t_70_g_se_x_16][]

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where
            QueryWrapper<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);
        }

[idea_SpringBoot_-CSDN]: https://blog.csdn.net/weixin_51309915/article/details/123349773?spm=1001.2014.3001.5501
[watermark_type_d3F5LXplbmhlaQ_shadow_50_text_Q1NETiBA5Y-r5oiR6ICB5Lyv_size_13_color_FFFFFF_t_70_g_se_x_16]: https://img-blog.csdnimg.cn/5b1cf38e1837424282b2b1f13418d276.png?x-oss-process=image/watermark,type_d3F5LXplbmhlaQ,shadow_50,text_Q1NETiBA5Y-r5oiR6ICB5Lyv,size_13,color_FFFFFF,t_70,g_se,x_16
[watermark_type_d3F5LXplbmhlaQ_shadow_50_text_Q1NETiBA5Y-r5oiR6ICB5Lyv_size_20_color_FFFFFF_t_70_g_se_x_16]: https://img-blog.csdnimg.cn/8f65976b61f340a89dc146a93c2cf60a.png?x-oss-process=image/watermark,type_d3F5LXplbmhlaQ,shadow_50,text_Q1NETiBA5Y-r5oiR6ICB5Lyv,size_20,color_FFFFFF,t_70,g_se,x_16