spring boot + mybatis使用Pagehelper分页

本文章前提是已经搭建好spring boot 和 mybatis框架，以下是分页过程

1、引入Pagehelper依赖

<dependency>
            <groupId>com.github.pagehelper</groupId>
            <artifactId>pagehelper</artifactId>
            <version>4.1.3</version>
        </dependency>

2、新建数据库表，我的测试表较为简单，只有三个参数：

3、在spring boot启动类配置pagehelper，我配置在main方法下面

public class SpringbootApplication {

    public static void main(String[] args) {
        SpringApplication.run(SpringbootApplication.class, args);

    }
    @Bean
    PageHelper pageHelper(){
        //分页插件
        PageHelper pageHelper = new PageHelper();
        Properties properties = new Properties();
        properties.setProperty("reasonable", "true");
        properties.setProperty("supportMethodsArguments", "true");
        properties.setProperty("returnPageInfo", "check");
        properties.setProperty("params", "count=countSql");
        pageHelper.setProperties(properties);

        //添加插件
        new SqlSessionFactoryBean().setPlugins(new Interceptor[]{pageHelper});
        return pageHelper;
    }

4、mapper文件实现调用数据库数据，返回结果类型为实体类类型：

<select id="getAll"  resultType="com.light.spring.Entity.Department">
        select id,name,descr from department
    </select>

5、在dao层建立接口文件，并在service层实现：

//dao层
@Mapper
@Component
public interface DepartmentMapper {
//使用list数组存值
    public List<Department> getAll();    
}

//service实现接口
@Service
public class DepartmentServiceImpl implements DepartmentService{
    @Autowired
    private DepartmentMapper departmentMapper;
    @Override
    public List<Department> getAll(){
        return  this.departmentMapper.getAll();
    }

}

6、controller层调用Pagehelper实现数据分页：

@PostMapping ("/helloworld")
    public PageInfo<Department> hello2(Integer PageNum,Integer PageSize){

        PageHelper.startPage(PageNum,PageSize);//第一个参数是当前页码，第二个参数是显示的列数
        List<Department> list=departmentServiceImpl.getAll();
        for (Department i: list
             ) {
            System.out.println(i);
        }
        PageInfo<Department> pageInfo = new PageInfo<Department>(list);
        return  pageInfo;
    }

7、测试：为了实现大量数据，用for循环写入多个数据到数据库，代码如下：

Department department=new Department();
        for (int i=0;i<100;i++){
            String name="Mapper"+i;
            String descr="Descr"+i*10;
            department.setName(name);
            department.setDescr(descr);
            this.departmentServiceImpl.insert(department);
        }

数据库数据如图：

接下来调用分页接口：
使用swagger测试，参数如下：

得到结果，成功：

{
  "endRow": 24,
  "firstPage": 4,
  "hasNextPage": true,
  "hasPreviousPage": true,
  "isFirstPage": false,
  "isLastPage": false,
  "lastPage": 11,
  "list": [
    {
      "descr": "Descr210",
      "id": 22,
      "name": "Mapper21"
    },
    {
      "descr": "Descr220",
      "id": 23,
      "name": "Mapper22"
    },
    {
      "descr": "Descr230",
      "id": 24,
      "name": "Mapper23"
    }
  ],
  "navigatePages": 8,
  "navigatepageNums": [
    4,
    5,
    6,
    7,
    8,
    9,
    10,
    11
  ],
  "nextPage": 9,
  "pageNum": 8,
  "pageSize": 3,
  "pages": 34,
  "prePage": 7,
  "size": 3,
  "startRow": 22,
  "total": 100
}

分页数据渲染到前端页面：https://blog.youkuaiyun.com/qq_39112803/article/details/85267083