使用pagehelper插件进行分页查询

一、导入mybatis和pagehelper坐标

<dependency>
       <groupId>org.mybatis.spring.boot</groupId>
       <artifactId>mybatis-spring-boot-starter</artifactId>
       <version>2.2.0</version>
</dependency>
<dependency>
      <groupId>com.github.pagehelper</groupId>
      <artifactId>pagehelper-spring-boot-starter</artifactId>
      <version>1.3.0</version>
</dependency>

二、配置数据库

spring:
  main:
    allow-circular-references: true
  datasource:
    druid:
      driver-class-name: com.mysql.cj.jdbc.Driver
      url: jdbc:mysql://localhost:3306/x_take_out?serverTimezone=Asia/Shanghai&useUnicode=true&characterEncoding=utf-8&zeroDateTimeBehavior=convertToNull&useSSL=false&allowPublicKeyRetrieval=true
      username: root
      password: root

三、编写代码实现分页

EmployeePageQueryDTO.java

@Data
public class EmployeePageQueryDTO implements Serializable {

    //员工姓名
    private String name;

    //页码
    private int page;

    //每页显示记录数
    private int pageSize;

}

EmployeeMapper.java

@Mapper
public interface EmployeeMapper {
    /**
     * 分页查询
     *
     * @param employeePageQueryDTO
     * @return
     */
    Page<Employee> pageQuery(EmployeePageQueryDTO employeePageQueryDTO);
}

EmployeeMapper.xml

    <select id="pageQuery" resultType="top.weiyuexin.x.entity.Employee">
        select *
        from employee
        <where>
            <if test="name != null and name != ''">
                and name like concat('%',#{name},'%')
            </if>
        </where>
        order by create_time desc
    </select>

EmployeeServiceImpl.java

/**
     * 员工分页查询
     *
     * @param employeePageQueryDTO
     * @return
     */
    @Override
    public PageResult pageQuery(EmployeePageQueryDTO employeePageQueryDTO) {
        // select * from employee limit 0,10
        // 使用PageHelper插件进行分页查询
        PageHelper.startPage(employeePageQueryDTO.getPage(), employeePageQueryDTO.getPageSize());

        Page<Employee> page = employeeMapper.pageQuery(employeePageQueryDTO);

        return new PageResult(page.getTotal(), page.getResult());
    }

四、接口测试