【MyBatis】PageHelper实现分页

分页

1.引入pom

普通mvc项目引入
<dependency>
    <groupId>com.github.pagehelpergroupId>
    <artifactId>pagehelperartifactId>
    <version>5.1.2version>
dependency>
springboot引入
      <dependency>
            <groupId>com.github.pagehelpergroupId>
            <artifactId>pagehelper-spring-boot-starterartifactId>
            <version>1.2.12version>
        dependency>

2.配置拦截器插件

在MyBatis的xml中配置拦截器插件

<plugins>
    
    <plugin interceptor="com.github.pagehelper.PageInterceptor">
        
        
    plugin>
plugins>

3.使用

DbStudents 实体类

import lombok.Data;

@Data
public class DbStudents {
    private Integer num;

    private String name;

    private Integer age;

    private String birthday;

    private String sex;

    private String address;

    private String major;

DbStudentsMapper 接口

package com.top.mapper;

import com.top.bean.DbStudents;
import java.util.List;
import org.springframework.stereotype.Repository;

@Repository
public interface DbStudentsMapper {
      
     /**
     * 多条件分页查询
     * @param dbStudents
     * @return
     */

     List<DbStudents> showAllInfo(DbStudents dbStudents);
}

DbStudentsMapper.xml
注意：sql 中就不要写 limit 了，pageHelp 会自己处理，sql 就按正常查询写法就好

<select id="showAllInfo" resultType="com.top.bean.DbStudents">
    SELECT
    <include refid="Base_Column_List"/>
    FROM
    db_students
    <where>
        <if test="num != null">
            num = #{num,jdbcType=INTEGER},
        if>
        <if test="name != null">
            name = #{name,jdbcType=VARCHAR},
        if>
        <if test="age != null">
            age = #{age,jdbcType=INTEGER},
        if>
        <if test="birthday != null">
            birthday = #{birthday,jdbcType=VARCHAR},
        if>
        <if test="sex != null">
            sex = #{sex,jdbcType=VARCHAR},
        if>
        <if test="address != null">
            address = #{address,jdbcType=VARCHAR},
        if>
        <if test="major != null">
            major = #{major,jdbcType=VARCHAR},
        if>
    where>
select>

DbStudentsService 业务层接口

public interface DbStudentsService {

    List<DbStudents> showAllInfo(DbStudents dbStudents);
}

DbStudentsServiceImpl 业务实现层

@Service
public class DbStudentsServiceImpl implements DbStudentsService {


    @Autowired
    private DbStudentsMapper dbStudentsMapper;


    @Override
    public List<DbStudents> showAllInfo(DbStudents dbStudents) {
        return dbStudentsMapper.showAllInfo(dbStudents);
    }
}

最后 DbStudentsController 控制层直接调用

/**
 * 分页查询所有信息
 */
@RequestMapping("showAllInfo")
@ResponseBody
public PageInfo<DbStudents> showAllInfo(@RequestParam(value = "currentPage", required = false, defaultValue = "1") Integer pageNum,
                                        @RequestParam(value = "pageSize", required = false, defaultValue = "3") Integer pageSize,
                                        DbStudents dbStudents) {
    // 使用mybatis的分页插件完成我们的分页查询
    PageHelper.startPage(pageNum, pageSize);
    List<DbStudents> employeeList = dbStudentsService.showAllInfo(dbStudents);
    PageInfo<DbStudents> pageInfo = new PageInfo(employeeList);
    return pageInfo;
}